spring-boot-referenc..

spring-boot-referenc..

Spring Boot Reference Guide

1.3.1.BUILD-SNAPSHOT

Phillip Webb , Dave Syer , Josh Long , Stéphane Nicoll , Rob Winch ,

Andy Wilkinson , Marcel Overdijk , Christian Dupuis , Sébastien Deleuze

Copyright © 2013-2015

Copies of this document may be made for your own use and for distribution to others, provided that you do not charge any fee for such copies and further provided that each copy contains this Copyright Notice, whether distributed in print or electronically.

Spring Boot Reference Guide

Table of Contents

I. Spring Boot Documentation ...................................................................................................... 1

1. About the documentation ................................................................................................ 2

2. Getting help .................................................................................................................... 3

3. First steps ...................................................................................................................... 4

4. Working with Spring Boot ................................................................................................ 5

5. Learning about Spring Boot features ................................................................................ 6

6. Moving to production ....................................................................................................... 7

7. Advanced topics ............................................................................................................. 8

II. Getting started ........................................................................................................................ 9

8. Introducing Spring Boot ................................................................................................. 10

9. System Requirements ................................................................................................... 11

9.1. Servlet containers ............................................................................................... 11

10. Installing Spring Boot .................................................................................................. 12

10.1. Installation instructions for the Java developer ................................................... 12

Maven installation ............................................................................................. 12

Gradle installation ............................................................................................. 13

10.2. Installing the Spring Boot CLI ........................................................................... 14

Manual installation ............................................................................................ 14

Installation with SDKMAN! ................................................................................. 15

OSX Homebrew installation ............................................................................... 15

MacPorts installation ......................................................................................... 15

Command-line completion ................................................................................. 16

Quick start Spring CLI example ......................................................................... 16

10.3. Upgrading from an earlier version of Spring Boot ............................................... 16

11. Developing your first Spring Boot application ................................................................ 17

11.1. Creating the POM ............................................................................................ 17

11.2. Adding classpath dependencies ........................................................................ 18

11.3. Writing the code ............................................................................................... 18

The @RestController and @RequestMapping annotations .................................. 19

The @EnableAutoConfiguration annotation ........................................................ 19

The “main” method ........................................................................................... 19

11.4. Running the example ........................................................................................ 20

11.5. Creating an executable jar ................................................................................ 20

12. What to read next ....................................................................................................... 22

III. Using Spring Boot ................................................................................................................ 23

13. Build systems ............................................................................................................. 24

13.1. Dependency management ................................................................................ 24

13.2. Maven .............................................................................................................. 24

Inheriting the starter parent ............................................................................... 24

Using Spring Boot without the parent POM ........................................................ 25

Changing the Java version ................................................................................ 26

Using the Spring Boot Maven plugin .................................................................. 26

13.3. Gradle .............................................................................................................. 26

13.4. Ant ................................................................................................................... 27

13.5. Starter POMs ................................................................................................... 28

14. Structuring your code .................................................................................................. 32

14.1. Using the “default” package .............................................................................. 32

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14.2. Locating the main application class ................................................................... 32

15. Configuration classes .................................................................................................. 34

15.1. Importing additional configuration classes .......................................................... 34

15.2. Importing XML configuration .............................................................................. 34

16. Auto-configuration ....................................................................................................... 35

16.1. Gradually replacing auto-configuration ............................................................... 35

16.2. Disabling specific auto-configuration .................................................................. 35

17. Spring Beans and dependency injection ....................................................................... 36

18. Using the @SpringBootApplication annotation .............................................................. 37

19. Running your application ............................................................................................. 38

19.1. Running from an IDE ........................................................................................ 38

19.2. Running as a packaged application ................................................................... 38

19.3. Using the Maven plugin .................................................................................... 38

19.4. Using the Gradle plugin .................................................................................... 39

19.5. Hot swapping ................................................................................................... 39

20. Developer tools ........................................................................................................... 40

20.1. Property defaults .............................................................................................. 40

20.2. Automatic restart .............................................................................................. 41

Excluding resources .......................................................................................... 42

Watching additional paths .................................................................................. 42

Disabling restart ................................................................................................ 42

Using a trigger file ............................................................................................ 43

Customizing the restart classloader .................................................................... 43

Known limitations .............................................................................................. 44

20.3. LiveReload ....................................................................................................... 44

20.4. Global settings ................................................................................................. 44

20.5. Remote applications ......................................................................................... 44

Running the remote client application ................................................................. 45

Remote update ................................................................................................. 46

Remote debug tunnel ........................................................................................ 46

21. Packaging your application for production ..................................................................... 47

22. What to read next ....................................................................................................... 48

IV. Spring Boot features ............................................................................................................ 49

23. SpringApplication ......................................................................................................... 50

23.1. Customizing the Banner .................................................................................... 50

23.2. Customizing SpringApplication .......................................................................... 51

23.3. Fluent builder API ............................................................................................. 52

23.4. Application events and listeners ........................................................................ 52

23.5. Web environment ............................................................................................. 53

23.6. Accessing application arguments ....................................................................... 53

23.7. Using the ApplicationRunner or CommandLineRunner ........................................ 53

23.8. Application exit ................................................................................................. 54

23.9. Admin features ................................................................................................. 54

24. Externalized Configuration ........................................................................................... 55

24.1. Configuring random values ............................................................................... 56

24.2. Accessing command line properties .................................................................. 56

24.3. Application property files ................................................................................... 56

24.4. Profile-specific properties .................................................................................. 57

24.5. Placeholders in properties ................................................................................. 58

24.6. Using YAML instead of Properties ..................................................................... 58

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Loading YAML .................................................................................................. 58

Exposing YAML as properties in the Spring Environment .................................... 59

Multi-profile YAML documents ........................................................................... 59

YAML shortcomings .......................................................................................... 60

24.7. Type-safe Configuration Properties .................................................................... 60

Third-party configuration .................................................................................... 61

Relaxed binding ................................................................................................ 61

Properties conversion ........................................................................................ 62

@ConfigurationProperties Validation .................................................................. 62

25. Profiles ....................................................................................................................... 64

25.1. Adding active profiles ....................................................................................... 64

25.2. Programmatically setting profiles ....................................................................... 64

25.3. Profile-specific configuration files ....................................................................... 65

26. Logging ....................................................................................................................... 66

26.1. Log format ....................................................................................................... 66

26.2. Console output ................................................................................................. 66

Color-coded output ............................................................................................ 67

26.3. File output ........................................................................................................ 68

26.4. Log Levels ....................................................................................................... 68

26.5. Custom log configuration .................................................................................. 69

26.6. Logback extensions .......................................................................................... 70

Profile-specific configuration .............................................................................. 71

Environment properties ...................................................................................... 71

27. Developing web applications ........................................................................................ 72

27.1. The ‘Spring Web MVC framework’ .................................................................... 72

Spring MVC auto-configuration .......................................................................... 72

HttpMessageConverters .................................................................................... 73

MessageCodesResolver .................................................................................... 73

Static Content ................................................................................................... 73

ConfigurableWebBindingInitializer ...................................................................... 75

Template engines .............................................................................................. 75

Error Handling .................................................................................................. 75

Error Handling on WebSphere Application Server ....................................... 77

Spring HATEOAS .............................................................................................. 77

CORS support .................................................................................................. 77

27.2. JAX-RS and Jersey .......................................................................................... 77

27.3. Embedded servlet container support .................................................................. 78

Servlets, Filters, and listeners ............................................................................ 79

Registering Servlets, Filters, and listeners as Spring beans ......................... 79

Servlet Context Initialization ............................................................................... 79

Scanning for Servlets, Filters, and listeners ................................................ 79

The EmbeddedWebApplicationContext ............................................................... 79

Customizing embedded servlet containers .......................................................... 80

Programmatic customization ...................................................................... 80

Customizing ConfigurableEmbeddedServletContainer directly ...................... 80

JSP limitations .................................................................................................. 81

28. Security ...................................................................................................................... 82

28.1. OAuth2 ............................................................................................................ 83

Authorization Server .......................................................................................... 83

Resource Server ............................................................................................... 83

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28.2. Token Type in User Info ................................................................................... 84

28.3. Customizing the User Info RestTemplate ........................................................... 84

Client ................................................................................................................ 84

Single Sign On ................................................................................................. 85

28.4. Actuator Security .............................................................................................. 86

29. Working with SQL databases ....................................................................................... 87

29.1. Configure a DataSource ................................................................................... 87

Embedded Database Support ............................................................................ 87

Connection to a production database ................................................................. 88

Connection to a JNDI DataSource ..................................................................... 88

29.2. Using JdbcTemplate ......................................................................................... 89

29.3. JPA and ‘Spring Data’ ...................................................................................... 89

Entity Classes ................................................................................................... 89

Spring Data JPA Repositories ........................................................................... 90

Creating and dropping JPA databases ............................................................... 91

29.4. Using H2’s web console ................................................................................... 91

Changing the H2 console’s path ........................................................................ 92

Securing the H2 console ................................................................................... 92

30. Using jOOQ ................................................................................................................ 93

30.1. Code Generation .............................................................................................. 93

30.2. Using DSLContext ............................................................................................ 93

30.3. Customizing jOOQ ............................................................................................ 94

31. Working with NoSQL technologies ............................................................................... 95

31.1. Redis ............................................................................................................... 95

Connecting to Redis .......................................................................................... 95

31.2. MongoDB ......................................................................................................... 95

Connecting to a MongoDB database .................................................................. 95

MongoTemplate ................................................................................................ 96

Spring Data MongoDB repositories .................................................................... 97

Embedded Mongo ............................................................................................. 97

31.3. Gemfire ............................................................................................................ 97

31.4. Solr .................................................................................................................. 98

Connecting to Solr ............................................................................................ 98

Spring Data Solr repositories ............................................................................. 98

31.5. Elasticsearch .................................................................................................... 98

Connecting to Elasticsearch .............................................................................. 99

Spring Data Elasticsearch repositories ............................................................... 99

31.6. Cassandra ........................................................................................................ 99

Connecting to Cassandra .................................................................................. 99

Spring Data Cassandra repositories ................................................................. 100

32. Caching .................................................................................................................... 101

32.1. Supported cache providers ............................................................................. 101

Generic ........................................................................................................... 102

JCache ........................................................................................................... 102

EhCache 2.x ................................................................................................... 102

Hazelcast ........................................................................................................ 103

Infinispan ........................................................................................................ 103

Redis .............................................................................................................. 103

Guava ............................................................................................................. 103

Simple ............................................................................................................ 104

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33. Messaging ................................................................................................................ 105

33.1. JMS ............................................................................................................... 105

ActiveMQ support ............................................................................................ 105

Artemis support ............................................................................................... 105

HornetQ support .............................................................................................. 105

Using a JNDI ConnectionFactory ..................................................................... 106

Sending a message ........................................................................................ 106

Receiving a message ...................................................................................... 107

33.2. AMQP ............................................................................................................ 107

RabbitMQ support ........................................................................................... 107

Sending a message ........................................................................................ 108

Receiving a message ...................................................................................... 108

34. Sending email ........................................................................................................... 109

35. Distributed Transactions with JTA .............................................................................. 110

35.1. Using an Atomikos transaction manager .......................................................... 110

35.2. Using a Bitronix transaction manager .............................................................. 110

35.3. Using a Java EE managed transaction manager .............................................. 111

35.4. Mixing XA and non-XA JMS connections ......................................................... 111

35.5. Supporting an alternative embedded transaction manager ................................ 111

36. Hazelcast .................................................................................................................. 112

37. Spring Integration ...................................................................................................... 113

38. Spring Session .......................................................................................................... 114

39. Monitoring and management over JMX ...................................................................... 115

40. Testing ...................................................................................................................... 116

40.1. Test scope dependencies ............................................................................... 116

40.2. Testing Spring applications ............................................................................. 116

40.3. Testing Spring Boot applications ..................................................................... 116

Using Spock to test Spring Boot applications .................................................... 118

40.4. Test utilities .................................................................................................... 118

ConfigFileApplicationContextInitializer ............................................................... 118

EnvironmentTestUtils ....................................................................................... 118

OutputCapture ................................................................................................. 118

TestRestTemplate ........................................................................................... 119

41. Creating your own auto-configuration ......................................................................... 120

41.1. Understanding auto-configured beans .............................................................. 120

41.2. Locating auto-configuration candidates ............................................................ 120

41.3. Condition annotations ..................................................................................... 120

Class conditions .............................................................................................. 121

Bean conditions .............................................................................................. 121

Property conditions .......................................................................................... 121

Resource conditions ........................................................................................ 121

Web application conditions .............................................................................. 121

SpEL expression conditions ............................................................................. 121

41.4. Creating your own starter ................................................................................ 122

Naming ........................................................................................................... 122

Autoconfigure module ...................................................................................... 122

Starter module ................................................................................................ 122

42. WebSockets .............................................................................................................. 124

43. What to read next ..................................................................................................... 125

V. Spring Boot Actuator: Production-ready features .................................................................. 126

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44. Enabling production-ready features ............................................................................ 127

45. Endpoints .................................................................................................................. 128

45.1. Customizing endpoints .................................................................................... 129

45.2. Hypermedia for actuator MVC endpoints .......................................................... 129

45.3. CORS support ................................................................................................ 130

45.4. Adding custom endpoints ................................................................................ 130

45.5. Health information .......................................................................................... 130

45.6. Security with HealthIndicators ......................................................................... 131

Auto-configured HealthIndicators ...................................................................... 131

Writing custom HealthIndicators ....................................................................... 131

45.7. Custom application info information ................................................................. 132

Automatically expand info properties at build time ............................................. 132

Automatic property expansion using Maven .............................................. 132

Automatic property expansion using Gradle .............................................. 133

Git commit information ..................................................................................... 134

46. Monitoring and management over HTTP .................................................................... 135

46.1. Securing sensitive endpoints ........................................................................... 135

46.2. Customizing the management endpoint paths .................................................. 135

46.3. Customizing the management server port ........................................................ 136

46.4. Customizing the management server address .................................................. 136

46.5. Disabling HTTP endpoints ............................................................................... 136

46.6. HTTP health endpoint access restrictions ........................................................ 136

47. Monitoring and management over JMX ...................................................................... 138

47.1. Customizing MBean names ............................................................................. 138

47.2. Disabling JMX endpoints ................................................................................. 138

47.3. Using Jolokia for JMX over HTTP ................................................................... 138

Customizing Jolokia ......................................................................................... 138

Disabling Jolokia ............................................................................................. 138

48. Monitoring and management using a remote shell ....................................................... 140

48.1. Connecting to the remote shell ........................................................................ 140

Remote shell credentials ................................................................................. 140

48.2. Extending the remote shell .............................................................................. 141

Remote shell commands ................................................................................. 141

Remote shell plugins ....................................................................................... 141

49. Metrics ...................................................................................................................... 142

49.1. System metrics ............................................................................................... 142

49.2. DataSource metrics ........................................................................................ 143

49.3. Cache metrics ................................................................................................ 143

49.4. Tomcat session metrics .................................................................................. 144

49.5. Recording your own metrics ............................................................................ 144

49.6. Adding your own public metrics ....................................................................... 144

49.7. Special features with Java 8 ........................................................................... 145

49.8. Metric writers, exporters and aggregation ......................................................... 145

Example: Export to Redis ................................................................................ 145

Example: Export to Open TSDB ...................................................................... 146

Example: Export to Statsd ............................................................................... 147

Example: Export to JMX .................................................................................. 147

49.9. Aggregating metrics from multiple sources ....................................................... 147

49.10. Dropwizard Metrics ....................................................................................... 148

49.11. Message channel integration ......................................................................... 148

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50. Auditing ..................................................................................................................... 149

51. Tracing ..................................................................................................................... 150

51.1. Custom tracing ............................................................................................... 150

52. Process monitoring .................................................................................................... 151

52.1. Extend configuration ....................................................................................... 151

52.2. Programmatically ............................................................................................ 151

53. What to read next ..................................................................................................... 152

VI. Deploying Spring Boot applications ..................................................................................... 153

54. Deploying to the cloud ............................................................................................... 154

54.1. Cloud Foundry ................................................................................................ 154

Binding to services .......................................................................................... 155

54.2. Heroku ........................................................................................................... 155

54.3. OpenShift ....................................................................................................... 157

54.4. Boxfuse and Amazon Web Services ................................................................ 157

54.5. Google App Engine ........................................................................................ 158

55. Installing Spring Boot applications .............................................................................. 159

55.1. Unix/Linux services ......................................................................................... 159

Installation as an init.d service (System V) ....................................................... 159

Installation as a systemd service ..................................................................... 160

Customizing the startup script .......................................................................... 160

Customizing the startup script with a conf file ................................................... 161

56. Microsoft Windows services ....................................................................................... 162

57. What to read next ..................................................................................................... 163

VII. Spring Boot CLI ................................................................................................................ 164

58. Installing the CLI ....................................................................................................... 165

59. Using the CLI ............................................................................................................ 166

59.1. Running applications using the CLI ................................................................. 166

Deduced “grab” dependencies ......................................................................... 167

Deduced “grab” coordinates ............................................................................. 168

Default import statements ................................................................................ 168

Automatic main method ................................................................................... 168

Custom dependency management ................................................................... 168

59.2. Testing your code ........................................................................................... 169

59.3. Applications with multiple source files .............................................................. 169

59.4. Packaging your application ............................................................................. 169

59.5. Initialize a new project .................................................................................... 170

59.6. Using the embedded shell .............................................................................. 170

59.7. Adding extensions to the CLI .......................................................................... 171

60. Developing application with the Groovy beans DSL ..................................................... 172

61. Configuring the CLI with settings.xml .......................................................................... 173

62. What to read next ..................................................................................................... 174

VIII. Build tool plugins ............................................................................................................. 175

63. Spring Boot Maven plugin .......................................................................................... 176

63.1. Including the plugin ........................................................................................ 176

63.2. Packaging executable jar and war files ............................................................ 177

64. Spring Boot Gradle plugin .......................................................................................... 178

64.1. Including the plugin ........................................................................................ 178

64.2. Gradle dependency management .................................................................... 178

64.3. Packaging executable jar and war files ............................................................ 179

64.4. Running a project in-place .............................................................................. 179

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64.5. Spring Boot plugin configuration ...................................................................... 180

64.6. Repackage configuration ................................................................................. 180

64.7. Repackage with custom Gradle configuration ................................................... 181

Configuration options ....................................................................................... 182

64.8. Understanding how the Gradle plugin works .................................................... 182

64.9. Publishing artifacts to a Maven repository using Gradle .................................... 183

Configuring Gradle to produce a pom that inherits dependency management ...... 183

Configuring Gradle to produce a pom that imports dependency management ...... 183

65. Spring Boot AntLib module ........................................................................................ 185

65.1. Spring Boot Ant tasks ..................................................................................... 185 spring-boot:exejar ............................................................................................ 185

Examples ................................................................................................ 185

65.2. spring-boot:findmainclass ................................................................................ 186

Examples ........................................................................................................ 186

66. Supporting other build systems .................................................................................. 187

66.1. Repackaging archives ..................................................................................... 187

66.2. Nested libraries .............................................................................................. 187

66.3. Finding a main class ....................................................................................... 187

66.4. Example repackage implementation ................................................................ 187

67. What to read next ..................................................................................................... 188

IX. ‘How-to’ guides .................................................................................................................. 189

68. Spring Boot application .............................................................................................. 190

68.1. Troubleshoot auto-configuration ....................................................................... 190

68.2. Customize the Environment or ApplicationContext before it starts ...................... 190

68.3. Build an ApplicationContext hierarchy (adding a parent or root context) .............. 191

68.4. Create a non-web application .......................................................................... 191

69. Properties & configuration .......................................................................................... 192

69.1. Externalize the configuration of SpringApplication ............................................. 192

69.2. Change the location of external properties of an application .............................. 192

69.3. Use ‘short’ command line arguments ............................................................... 193

69.4. Use YAML for external properties .................................................................... 193

69.5. Set the active Spring profiles .......................................................................... 194

69.6. Change configuration depending on the environment ........................................ 194

69.7. Discover built-in options for external properties ................................................ 195

70. Embedded servlet containers ..................................................................................... 196

70.1. Add a Servlet, Filter or Listener to an application .............................................. 196

Add a Servlet, Filter or Listener using a Spring bean ......................................... 196

Disable registration of a Servlet or Filter ................................................... 196

Add Servlets, Filters, and Listeners using classpath scanning ............................ 196

70.2. Change the HTTP port ................................................................................... 197

70.3. Use a random unassigned HTTP port .............................................................. 197

70.4. Discover the HTTP port at runtime .................................................................. 197

70.5. Configure SSL ................................................................................................ 197

70.6. Use behind a front-end proxy server ................................................................ 198

Customize Tomcat’s proxy configuration ........................................................... 198

70.7. Configure Tomcat ........................................................................................... 199

70.8. Enable Multiple Connectors with Tomcat ......................................................... 199

70.9. Use Jetty instead of Tomcat ........................................................................... 199

70.10. Configure Jetty ............................................................................................. 200

70.11. Use Undertow instead of Tomcat ................................................................... 200

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70.12. Configure Undertow ...................................................................................... 201

70.13. Enable Multiple Listeners with Undertow ........................................................ 201

70.14. Use Tomcat 7 ............................................................................................... 201

Use Tomcat 7 with Maven ............................................................................... 201

Use Tomcat 7 with Gradle ............................................................................... 201

70.15. Use Jetty 8 ................................................................................................... 202

Use Jetty 8 with Maven ................................................................................... 202

Use Jetty 8 with Gradle ................................................................................... 202

70.16. Create WebSocket endpoints using @ServerEndpoint .................................... 202

70.17. Enable HTTP response compression ............................................................. 203

71. Spring MVC .............................................................................................................. 204

71.1. Write a JSON REST service ........................................................................... 204

71.2. Write an XML REST service ........................................................................... 204

71.3. Customize the Jackson ObjectMapper ............................................................. 204

71.4. Customize the @ResponseBody rendering ...................................................... 206

71.5. Handling Multipart File Uploads ....................................................................... 206

71.6. Switch off the Spring MVC DispatcherServlet ................................................... 206

71.7. Switch off the Default MVC configuration ......................................................... 206

71.8. Customize ViewResolvers ............................................................................... 207

71.9. Velocity .......................................................................................................... 208

72. Logging ..................................................................................................................... 209

72.1. Configure Logback for logging ......................................................................... 209

Configure logback for file only output ............................................................... 210

72.2. Configure Log4j for logging ............................................................................. 210

Use YAML or JSON to configure Log4j 2 ......................................................... 211

73. Data Access ............................................................................................................. 212

73.1. Configure a DataSource .................................................................................. 212

73.2. Configure Two DataSources ........................................................................... 212

73.3. Use Spring Data repositories .......................................................................... 212

73.4. Separate @Entity definitions from Spring configuration ..................................... 213

73.5. Configure JPA properties ................................................................................ 213

73.6. Use a custom EntityManagerFactory ............................................................... 213

73.7. Use Two EntityManagers ................................................................................ 213

73.8. Use a traditional persistence.xml ..................................................................... 214

73.9. Use Spring Data JPA and Mongo repositories .................................................. 214

73.10. Expose Spring Data repositories as REST endpoint ........................................ 215

74. Database initialization ................................................................................................ 216

74.1. Initialize a database using JPA ....................................................................... 216

74.2. Initialize a database using Hibernate ............................................................... 216

74.3. Initialize a database using Spring JDBC .......................................................... 216

74.4. Initialize a Spring Batch database ................................................................... 217

74.5. Use a higher level database migration tool ....................................................... 217

Execute Flyway database migrations on startup ................................................ 217

Execute Liquibase database migrations on startup ............................................ 217

75. Batch applications ..................................................................................................... 218

75.1. Execute Spring Batch jobs on startup .............................................................. 218

76. Actuator .................................................................................................................... 219

76.1. Change the HTTP port or address of the actuator endpoints ............................. 219

76.2. Customize the ‘whitelabel’ error page .............................................................. 219

76.3. Actuator and Jersey ........................................................................................ 219

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77. Security ..................................................................................................................... 220

77.1. Switch off the Spring Boot security configuration .............................................. 220

77.2. Change the AuthenticationManager and add user accounts .............................. 220

77.3. Enable HTTPS when running behind a proxy server ......................................... 220

78. Hot swapping ............................................................................................................ 222

78.1. Reload static content ...................................................................................... 222

78.2. Reload templates without restarting the container ............................................. 222

Thymeleaf templates ....................................................................................... 222

FreeMarker templates ...................................................................................... 222

Groovy templates ............................................................................................ 222

Velocity templates ........................................................................................... 222

78.3. Fast application restarts .................................................................................. 222

78.4. Reload Java classes without restarting the container ........................................ 222

Configuring Spring Loaded for use with Maven ................................................. 223

Configuring Spring Loaded for use with Gradle and IntelliJ IDEA ........................ 223

79. Build ......................................................................................................................... 224

79.1. Customize dependency versions ..................................................................... 224

79.2. Create an executable JAR with Maven ............................................................ 224

79.3. Create an additional executable JAR ............................................................... 225

79.4. Extract specific libraries when an executable jar runs ....................................... 225

79.5. Create a non-executable JAR with exclusions .................................................. 226

79.6. Remote debug a Spring Boot application started with Maven ............................. 227

79.7. Remote debug a Spring Boot application started with Gradle ............................. 227

79.8. Build an executable archive from Ant without using spring-boot-antlib ................ 227

79.9. How to use Java 6 ......................................................................................... 228

Embedded servlet container compatibility ......................................................... 228

JTA API compatibility ...................................................................................... 228

80. Traditional deployment ............................................................................................... 229

80.1. Create a deployable war file ........................................................................... 229

80.2. Create a deployable war file for older servlet containers .................................... 230

80.3. Convert an existing application to Spring Boot .................................................. 230

80.4. Deploying a WAR to WebLogic ....................................................................... 231

80.5. Deploying a WAR in an Old (Servlet 2.5) Container .......................................... 232

X. Appendices ......................................................................................................................... 234

A. Common application properties ................................................................................... 235

B. Configuration meta-data .............................................................................................. 251

B.1. Meta-data format .............................................................................................. 251

Group Attributes .............................................................................................. 252

Property Attributes ........................................................................................... 253

Hint Attributes ................................................................................................. 254

Repeated meta-data items ............................................................................... 255

B.2. Providing manual hints ..................................................................................... 255

Value hint ....................................................................................................... 255

Value provider ................................................................................................. 256

Any ......................................................................................................... 256

Class reference ....................................................................................... 257

Handle As ............................................................................................... 258

Logger name .......................................................................................... 258

Spring bean reference ............................................................................. 259

Spring profile name ................................................................................. 260

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B.3. Generating your own meta-data using the annotation processor .......................... 260

Nested properties ............................................................................................ 261

Adding additional meta-data ............................................................................ 261

C. Auto-configuration classes ........................................................................................... 263

C.1. From the “spring-boot-autoconfigure” module .................................................... 263

C.2. From the “spring-boot-actuator” module ............................................................ 266

D. The executable jar format ........................................................................................... 267

D.1. Nested JARs ................................................................................................... 267

The executable jar file structure ....................................................................... 267

The executable war file structure ..................................................................... 267

D.2. Spring Boot’s “JarFile” class ............................................................................. 268

Compatibility with the standard Java “JarFile” ................................................... 268

D.3. Launching executable jars ................................................................................ 268

Launcher manifest ........................................................................................... 269

Exploded archives ........................................................................................... 269

D.4. PropertiesLauncher Features ............................................................................ 269

D.5. Executable jar restrictions ................................................................................ 270

Zip entry compression ..................................................................................... 270

System ClassLoader ....................................................................................... 270

D.6. Alternative single jar solutions .......................................................................... 271

E. Dependency versions .................................................................................................. 272

1.3.1.BUILD-SNAPSHOT Spring Boot xii

Part I. Spring Boot Documentation

This section provides a brief overview of Spring Boot reference documentation. Think of it as map for the rest of the document. You can read this reference guide in a linear fashion, or you can skip sections if something doesn’t interest you.

Spring Boot Reference Guide

1. About the documentation

The Spring Boot reference guide is available as html , pdf and epub documents. The latest copy is available at docs.spring.io/spring-boot/docs/current/reference .

Copies of this document may be made for your own use and for distribution to others, provided that you do not charge any fee for such copies and further provided that each copy contains this Copyright

Notice, whether distributed in print or electronically.

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Spring Boot Reference Guide

2. Getting help

Having trouble with Spring Boot, We’d like to help!

• Try the

How-to’s

— they provide solutions to the most common questions.

• Learn the Spring basics — Spring Boot builds on many other Spring projects, check the spring.io

website for a wealth of reference documentation. If you are just starting out with Spring, try one of the guides .

• Ask a question - we monitor stackoverflow.com

for questions tagged with spring-boot

.

• Report bugs with Spring Boot at github.com/spring-projects/spring-boot/issues .

Note

All of Spring Boot is open source, including the documentation! If you find problems with the docs; or if you just want to improve them, please get involved .

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3. First steps

If you’re just getting started with Spring Boot, or 'Spring' in general,

this is the place to start!

From scratch: Overview |

Requirements

|

Installation

Tutorial: Part 1

| Part 2

Running your example:

Part 1 | Part 2

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4. Working with Spring Boot

Ready to actually start using Spring Boot? We’ve got you covered

.

Build systems:

Maven |

Gradle

| Ant |

Starter POMs

Best practices:

Code Structure |

@Configuration

|

@EnableAutoConfiguration |

Beans and

Dependency Injection

Running your code

IDE | Packaged | Maven

| Gradle

Packaging your app:

Production jars

Spring Boot CLI: Using the CLI

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5. Learning about Spring Boot features

Need more details about Spring Boot’s core features? This is for you

!

Core Features: SpringApplication |

External Configuration

|

Profiles |

Logging

Web Applications: MVC

|

Embedded Containers

Working with data: SQL

|

NO-SQL

Messaging:

Overview | JMS

Testing:

Overview | Boot Applications

| Utils

Extending:

Auto-configuration

|

@Conditions

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6. Moving to production

When you’re ready to push your Spring Boot application to production, we’ve got some tricks that you might like

!

Management endpoints:

Overview

| Customization

Connection options: HTTP

| JMX

|

SSH

Monitoring:

Metrics |

Auditing

|

Tracing |

Process

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7. Advanced topics

Lastly, we have a few topics for the more advanced user.

Deploy Spring Boot Applications: Cloud Deployment |

OS Service

Build tool plugins:

Maven |

Gradle

Appendix:

Application Properties

|

Auto-configuration classes |

Executable Jars

1.3.1.BUILD-SNAPSHOT Spring Boot 8

Part II. Getting started

If you’re just getting started with Spring Boot, or 'Spring' in general, this is the section for you! Here we answer the basic “what?”, “how?” and “why?” questions. You’ll find a gentle introduction to Spring Boot along with installation instructions. We’ll then build our first Spring Boot application, discussing some core principles as we go.

Spring Boot Reference Guide

8. Introducing Spring Boot

Spring Boot makes it easy to create stand-alone, production-grade Spring based Applications that you can “just run”. We take an opinionated view of the Spring platform and third-party libraries so you can get started with minimum fuss. Most Spring Boot applications need very little Spring configuration.

You can use Spring Boot to create Java applications that can be started using java -jar

or more traditional war deployments. We also provide a command line tool that runs “spring scripts”.

Our primary goals are:

• Provide a radically faster and widely accessible getting started experience for all Spring development.

• Be opinionated out of the box, but get out of the way quickly as requirements start to diverge from the defaults.

• Provide a range of non-functional features that are common to large classes of projects (e.g.

embedded servers, security, metrics, health checks, externalized configuration).

• Absolutely no code generation and no requirement for XML configuration.

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9. System Requirements

By default, Spring Boot 1.3.1.BUILD-SNAPSHOT requires Java 7 and Spring Framework 4.1.5 or above.

You can use Spring Boot with Java 6 with some additional configuration. See Section 79.9, “How to use

Java 6”

for more details. Explicit build support is provided for Maven (3.2+) and Gradle (1.12+).

Tip

Although you can use Spring Boot with Java 6 or 7, we generally recommend Java 8 if at all possible.

9.1 Servlet containers

The following embedded servlet containers are supported out of the box:

Name

Tomcat 8

Tomcat 7

Jetty 9

Jetty 8

Undertow 1.1

Servlet Version

3.1

3.0

3.1

3.0

3.1

Java Version

Java 7+

Java 6+

Java 7+

Java 6+

Java 7+

You can also deploy Spring Boot applications to any Servlet 3.0+ compatible container.

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10. Installing Spring Boot

Spring Boot can be used with “classic” Java development tools or installed as a command line tool.

Regardless, you will need Java SDK v1.6

or higher. You should check your current Java installation before you begin:

$ java -version

If you are new to Java development, or if you just want to experiment with Spring Boot you might want to try the

Spring Boot CLI

first, otherwise, read on for “classic” installation instructions.

Tip

Although Spring Boot is compatible with Java 1.6, if possible, you should consider using the latest version of Java.

10.1 Installation instructions for the Java developer

You can use Spring Boot in the same way as any standard Java library. Simply include the appropriate spring-boot-*.jar

files on your classpath. Spring Boot does not require any special tools integration, so you can use any IDE or text editor; and there is nothing special about a Spring Boot application, so you can run and debug as you would any other Java program.

Although you could just copy Spring Boot jars, we generally recommend that you use a build tool that supports dependency management (such as Maven or Gradle).

Maven installation

Spring Boot is compatible with Apache Maven 3.2 or above. If you don’t already have Maven installed you can follow the instructions at maven.apache.org

.

Tip

On many operating systems Maven can be installed via a package manager. If you’re an OSX

Homebrew user try brew install maven

. Ubuntu users can run sudo apt-get install maven

.

Spring Boot dependencies use the org.springframework.boot

groupId

. Typically your Maven

POM file will inherit from the spring-boot-starter-parent

project and declare dependencies to

one or more “Starter POMs”

. Spring Boot also provides an optional

Maven plugin

to create executable jars.

Here is a typical pom.xml

file:

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns

=

"http://maven.apache.org/POM/4.0.0" xmlns:xsi

=

"http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation

=

"http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" >

<modelVersion>

4.0.0

</modelVersion>

<groupId>

com.example

</groupId>

<artifactId>

myproject

</artifactId>

<version>

0.0.1-SNAPSHOT

</version>

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<!-- Inherit defaults from Spring Boot -->

<parent>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter-parent

</artifactId>

<version>

1.3.1.BUILD-SNAPSHOT

</version>

</parent>

<!-- Add typical dependencies for a web application -->

<dependencies>

<dependency>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter-web

</artifactId>

</dependency>

</dependencies>

<!-- Package as an executable jar -->

<build>

<plugins>

<plugin>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-maven-plugin

</artifactId>

</plugin>

</plugins>

</build>

<!-- Add Spring repositories -->

<!-- (you don't need this if you are using a .RELEASE version) -->

<repositories>

<repository>

<id>

spring-snapshots

</id>

<url>

http://repo.spring.io/snapshot

</url>

<snapshots><enabled>

true

</enabled></snapshots>

</repository>

<repository>

<id>

spring-milestones

</id>

<url>

http://repo.spring.io/milestone

</url>

</repository>

</repositories>

<pluginRepositories>

<pluginRepository>

<id>

spring-snapshots

</id>

<url>

http://repo.spring.io/snapshot

</url>

</pluginRepository>

<pluginRepository>

<id>

spring-milestones

</id>

<url>

http://repo.spring.io/milestone

</url>

</pluginRepository>

</pluginRepositories>

</project>

Tip

The spring-boot-starter-parent

is a great way to use Spring Boot, but it might not be suitable all of the time. Sometimes you may need to inherit from a different parent POM, or you

might just not like our default settings. See the section called “Using Spring Boot without the parent

POM”

for an alternative solution that uses an import

scope.

Gradle installation

Spring Boot is compatible with Gradle 1.12 or above. If you don’t already have Gradle installed you can follow the instructions at www.gradle.org/ .

Spring Boot dependencies can be declared using the org.springframework.boot

group

. Typically your project will declare dependencies to one or more

“Starter POMs” . Spring Boot provides a useful

Gradle plugin

that can be used to simplify dependency declarations and to create executable jars.

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Gradle Wrapper

The Gradle Wrapper provides a nice way of “obtaining” Gradle when you need to build a project.

It’s a small script and library that you commit alongside your code to bootstrap the build process.

See www.gradle.org/docs/current/userguide/gradle_wrapper.html

for details.

Here is a typical build.gradle

file: buildscript {

repositories {

jcenter()

maven { url

"http://repo.spring.io/snapshot"

}

maven { url

"http://repo.spring.io/milestone"

}

}

dependencies {

classpath(

"org.springframework.boot:spring-boot-gradle-plugin:1.3.1.BUILD-SNAPSHOT"

)

}

} apply plugin:

'java'

apply plugin:

'spring-boot'

jar {

baseName =

'myproject'

version =

'0.0.1-SNAPSHOT'

} repositories {

jcenter()

maven { url

"http://repo.spring.io/snapshot"

}

maven { url

"http://repo.spring.io/milestone"

}

} dependencies {

compile(

"org.springframework.boot:spring-boot-starter-web"

)

testCompile(

"org.springframework.boot:spring-boot-starter-test"

)

}

10.2 Installing the Spring Boot CLI

The Spring Boot CLI is a command line tool that can be used if you want to quickly prototype with Spring.

It allows you to run Groovy scripts, which means that you have a familiar Java-like syntax, without so much boilerplate code.

You don’t need to use the CLI to work with Spring Boot but it’s definitely the quickest way to get a Spring application off the ground.

Manual installation

You can download the Spring CLI distribution from the Spring software repository:

• spring-boot-cli-1.3.1.BUILD-SNAPSHOT-bin.zip

• spring-boot-cli-1.3.1.BUILD-SNAPSHOT-bin.tar.gz

Cutting edge snapshot distributions are also available.

Once downloaded, follow the INSTALL.txt

instructions from the unpacked archive. In summary: there is a spring

script ( spring.bat

for Windows) in a bin/

directory in the

.zip

file, or alternatively you can use java -jar

with the

.jar

file (the script helps you to be sure that the classpath is set correctly).

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Installation with SDKMAN!

SDKMAN! (The Software Development Kit Manager) can be used for managing multiple versions of various binary SDKs, including Groovy and the Spring Boot CLI. Get SDKMAN! from sdkman.io

and install Spring Boot with

$ sdk install springboot

$ spring --version

Spring Boot v1.3.1.BUILD-SNAPSHOT

If you are developing features for the CLI and want easy access to the version you just built, follow these extra instructions.

$ sdk install springboot dev /path/to/spring-boot/spring-boot-cli/target/spring-boot-cli-1.3.1.BUILD-

SNAPSHOT-bin/spring-1.3.1.BUILD-SNAPSHOT/

$ sdk default springboot dev

$ spring --version

Spring CLI v1.3.1.BUILD-SNAPSHOT

This will install a local instance of spring

called the dev

instance. It points at your target build location, so every time you rebuild Spring Boot, spring

will be up-to-date.

You can see it by doing this:

$ sdk ls springboot

================================================================================

Available Springboot Versions

================================================================================

> + dev

* 1.3.1.BUILD-SNAPSHOT

================================================================================

+ - local version

* - installed

> - currently in use

================================================================================

OSX Homebrew installation

If you are on a Mac and using Homebrew , all you need to do to install the Spring Boot CLI is:

$ brew tap pivotal/tap

$ brew install springboot

Homebrew will install spring

to

/usr/local/bin

.

Note

If you don’t see the formula, your installation of brew might be out-of-date. Just execute brew update

and try again.

MacPorts installation

If you are on a Mac and using MacPorts , all you need to do to install the Spring Boot CLI is:

$ sudo port install spring-boot-cli

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Command-line completion

Spring Boot CLI ships with scripts that provide command completion for BASH and zsh shells. You can source

the script (also named spring

) in any shell, or put it in your personal or system-wide bash completion initialization. On a Debian system the system-wide scripts are in

/shell-completion/ bash

and all scripts in that directory are executed when a new shell starts. To run the script manually, e.g. if you have installed using SDKMAN!

$ . ~/.sdkman/springboot/current/shell-completion/bash/spring

$ spring <HIT TAB HERE>

grab help jar run test version

Note

If you install Spring Boot CLI using Homebrew or MacPorts, the command-line completion scripts are automatically registered with your shell.

Quick start Spring CLI example

Here’s a really simple web application that you can use to test your installation. Create a file called app.groovy

:

@RestController

class

ThisWillActuallyRun {

@RequestMapping("/")

String home() {

"Hello World!"

}

}

Then simply run it from a shell:

$ spring run app.groovy

Note

It will take some time when you first run the application as dependencies are downloaded.

Subsequent runs will be much quicker.

Open localhost:8080 in your favorite web browser and you should see the following output:

Hello World!

10.3 Upgrading from an earlier version of Spring Boot

If you are upgrading from an earlier release of Spring Boot check the “release notes” hosted on the project wiki . You’ll find upgrade instructions along with a list of “new and noteworthy” features for each release.

To upgrade an existing CLI installation use the appropriate package manager command (for example brew upgrade

) or, if you manually installed the CLI, follow the

standard instructions

remembering to update your

PATH

environment variable to remove any older references.

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11. Developing your first Spring Boot application

Let’s develop a simple “Hello World!” web application in Java that highlights some of Spring Boot’s key features. We’ll use Maven to build this project since most IDEs support it.

Tip

The spring.io

web site contains many “Getting Started” guides that use Spring Boot. If you’re looking to solve a specific problem; check there first.

Before we begin, open a terminal to check that you have valid versions of Java and Maven installed.

$ java -version java version "1.7.0_51"

Java(TM) SE Runtime Environment (build 1.7.0_51-b13)

Java HotSpot(TM) 64-Bit Server VM (build 24.51-b03, mixed mode)

$ mvn -v

Apache Maven 3.2.3 (33f8c3e1027c3ddde99d3cdebad2656a31e8fdf4; 2014-08-11T13:58:10-07:00)

Maven home: /Users/user/tools/apache-maven-3.1.1

Java version: 1.7.0_51, vendor: Oracle Corporation

Note

This sample needs to be created in its own folder. Subsequent instructions assume that you have created a suitable folder and that it is your “current directory”.

11.1 Creating the POM

We need to start by creating a Maven pom.xml

file. The pom.xml

is the recipe that will be used to build your project. Open your favorite text editor and add the following:

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns

=

"http://maven.apache.org/POM/4.0.0" xmlns:xsi

=

"http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation

=

"http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" >

<modelVersion>

4.0.0

</modelVersion>

<groupId>

com.example

</groupId>

<artifactId>

myproject

</artifactId>

<version>

0.0.1-SNAPSHOT

</version>

<parent>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter-parent

</artifactId>

<version>

1.3.1.BUILD-SNAPSHOT

</version>

</parent>

<!-- Additional lines to be added here... -->

<!-- (you don't need this if you are using a .RELEASE version) -->

<repositories>

<repository>

<id>

spring-snapshots

</id>

<url>

http://repo.spring.io/snapshot

</url>

<snapshots><enabled>

true

</enabled></snapshots>

</repository>

<repository>

<id>

spring-milestones

</id>

<url>

http://repo.spring.io/milestone

</url>

</repository>

</repositories>

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<pluginRepositories>

<pluginRepository>

<id>

spring-snapshots

</id>

<url>

http://repo.spring.io/snapshot

</url>

</pluginRepository>

<pluginRepository>

<id>

spring-milestones

</id>

<url>

http://repo.spring.io/milestone

</url>

</pluginRepository>

</pluginRepositories>

</project>

This should give you a working build, you can test it out by running mvn package

(you can ignore the

“jar will be empty - no content was marked for inclusion!” warning for now).

Note

At this point you could import the project into an IDE (most modern Java IDE’s include built-in support for Maven). For simplicity, we will continue to use a plain text editor for this example.

11.2 Adding classpath dependencies

Spring Boot provides a number of “Starter POMs” that make easy to add jars to your classpath. Our sample application has already used spring-boot-starter-parent

in the parent

section of the

POM. The spring-boot-starter-parent

is a special starter that provides useful Maven defaults.

It also provides a dependency-management

section so that you can omit

version

tags for “blessed” dependencies.

Other “Starter POMs” simply provide dependencies that you are likely to need when developing a specific type of application. Since we are developing a web application, we will add a spring-bootstarter-web

dependency — but before that, let’s look at what we currently have.

$ mvn dependency:tree

[INFO] com.example:myproject:jar:0.0.1-SNAPSHOT

The mvn dependency:tree

command prints a tree representation of your project dependencies.

You can see that spring-boot-starter-parent

provides no dependencies by itself. Let’s edit our pom.xml

and add the spring-boot-starter-web

dependency just below the parent

section:

<dependencies>

<dependency>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter-web

</artifactId>

</dependency>

</dependencies>

If you run mvn dependency:tree

again, you will see that there are now a number of additional dependencies, including the Tomcat web server and Spring Boot itself.

11.3 Writing the code

To finish our application we need to create a single Java file. Maven will compile sources from src/ main/java

by default so you need to create that folder structure, then add a file named src/main/ java/Example.java

:

import

org.springframework.boot.*;

import

org.springframework.boot.autoconfigure.*;

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import

org.springframework.stereotype.*;

import

org.springframework.web.bind.annotation.*;

@RestController

@EnableAutoConfiguration

public class

Example {

@RequestMapping("/")

String home() {

return

"Hello World!"

;

}

public static void

main(String[] args)

throws

Exception {

SpringApplication.run(Example.

class

, args);

}

}

Although there isn’t much code here, quite a lot is going on. Let’s step through the important parts.

The @RestController and @RequestMapping annotations

The first annotation on our

Example

class is

@RestController

. This is known as a stereotype annotation. It provides hints for people reading the code, and for Spring, that the class plays a specific role. In this case, our class is a web

@Controller

so Spring will consider it when handling incoming web requests.

The

@RequestMapping

annotation provides “routing” information. It is telling Spring that any HTTP request with the path “/” should be mapped to the home

method. The

@RestController

annotation tells Spring to render the resulting string directly back to the caller.

Tip

The

@RestController

and

@RequestMapping

annotations are Spring MVC annotations (they are not specific to Spring Boot). See the MVC section in the Spring Reference Documentation for more details.

The @EnableAutoConfiguration annotation

The second class-level annotation is

@EnableAutoConfiguration

. This annotation tells Spring

Boot to “guess” how you will want to configure Spring, based on the jar dependencies that you have added. Since spring-boot-starter-web

added Tomcat and Spring MVC, the auto-configuration will assume that you are developing a web application and setup Spring accordingly.

Starter POMs and Auto-Configuration

Auto-configuration is designed to work well with “Starter POMs”, but the two concepts are not directly tied. You are free to pick-and-choose jar dependencies outside of the starter POMs and

Spring Boot will still do its best to auto-configure your application.

The “main” method

The final part of our application is the main

method. This is just a standard method that follows the Java convention for an application entry point. Our main method delegates to Spring Boot’s

SpringApplication

class by calling run

.

SpringApplication

will bootstrap our application, starting Spring which will in turn start the auto-configured Tomcat web server. We need to pass

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Example.class

as an argument to the run

method to tell

SpringApplication

which is the primary

Spring component. The args

array is also passed through to expose any command-line arguments.

11.4 Running the example

At this point our application should work. Since we have used the spring-boot-starter-parent

POM we have a useful run

goal that we can use to start the application. Type mvn spring-boot:run from the root project directory to start the application:

$ mvn spring-boot:run

. ____ _ __ _ _

/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \

( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \

\\/ ___)| |_)| | | | | || (_| | ) ) ) )

' |____| .__|_| |_|_| |_\__, | / / / /

=========|_|==============|___/=/_/_/_/

:: Spring Boot :: (v1.3.1.BUILD-SNAPSHOT)

....... . . .

....... . . . (log output here)

....... . . .

........ Started Example in 2.222 seconds (JVM running for 6.514)

If you open a web browser to localhost:8080 you should see the following output:

Hello World!

To gracefully exit the application hit ctrl-c

.

11.5 Creating an executable jar

Let’s finish our example by creating a completely self-contained executable jar file that we could run in production. Executable jars (sometimes called “fat jars”) are archives containing your compiled classes along with all of the jar dependencies that your code needs to run.

Executable jars and Java

Java does not provide any standard way to load nested jar files (i.e. jar files that are themselves contained within a jar). This can be problematic if you are looking to distribute a self-contained application.

To solve this problem, many developers use “uber” jars. An uber jar simply packages all classes, from all jars, into a single archive. The problem with this approach is that it becomes hard to see which libraries you are actually using in your application. It can also be problematic if the same filename is used (but with different content) in multiple jars.

Spring Boot takes a different approach

and allows you to actually nest jars directly.

To create an executable jar we need to add the spring-boot-maven-plugin

to our pom.xml

. Insert the following lines just below the dependencies

section:

<build>

<plugins>

<plugin>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-maven-plugin

</artifactId>

</plugin>

</plugins>

</build>

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Note

The spring-boot-starter-parent

POM includes

<executions>

configuration to bind the repackage

goal. If you are not using the parent POM you will need to declare this configuration yourself. See the plugin documentation for details.

Save your pom.xml

and run mvn package

from the command line:

$ mvn package

[INFO] Scanning for projects...

[INFO]

[INFO] ------------------------------------------------------------------------

[INFO] Building myproject 0.0.1-SNAPSHOT

[INFO] ------------------------------------------------------------------------

[INFO] .... ..

[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ myproject ---

[INFO] Building jar: /Users/developer/example/spring-boot-example/target/myproject-0.0.1-SNAPSHOT.jar

[INFO]

[INFO] --- spring-boot-maven-plugin:1.3.1.BUILD-SNAPSHOT:repackage (default) @ myproject ---

[INFO] ------------------------------------------------------------------------

[INFO] BUILD SUCCESS

[INFO] ------------------------------------------------------------------------

If you look in the target

directory you should see myproject-0.0.1-SNAPSHOT.jar

. The file should be around 10 Mb in size. If you want to peek inside, you can use jar tvf

:

$ jar tvf target/myproject-0.0.1-SNAPSHOT.jar

You should also see a much smaller file named myproject-0.0.1-SNAPSHOT.jar.original

in the target

directory. This is the original jar file that Maven created before it was repackaged by Spring

Boot.

To run that application, use the java -jar

command:

$ java -jar target/myproject-0.0.1-SNAPSHOT.jar

. ____ _ __ _ _

/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \

( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \

\\/ ___)| |_)| | | | | || (_| | ) ) ) )

' |____| .__|_| |_|_| |_\__, | / / / /

=========|_|==============|___/=/_/_/_/

:: Spring Boot :: (v1.3.1.BUILD-SNAPSHOT)

....... . . .

....... . . . (log output here)

....... . . .

........ Started Example in 2.536 seconds (JVM running for 2.864)

As before, to gracefully exit the application hit ctrl-c

.

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12. What to read next

Hopefully this section has provided you with some of the Spring Boot basics, and got you on your way to writing your own applications. If you’re a task-oriented type of developer you might want to jump over to spring.io

and check out some of the getting started guides that solve specific “How do I do that with

Spring” problems; we also have Spring Boot-specific

How-to

reference documentation.

The Spring Boot repository has also a bunch of samples you can run. The samples are independent of the rest of the code (that is you don’t need to build the rest to run or use the samples).

Otherwise, the next logical step is to read

Part III, “Using Spring Boot”

. If you’re really impatient, you

could also jump ahead and read about

Spring Boot features

.

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Part III. Using Spring Boot

This section goes into more detail about how you should use Spring Boot. It covers topics such as build systems, auto-configuration and how to run your applications. We also cover some Spring Boot best practices. Although there is nothing particularly special about Spring Boot (it is just another library that you can consume), there are a few recommendations that, when followed, will make your development process just a little easier.

If you’re just starting out with Spring Boot, you should probably read the

Getting Started

guide before diving into this section.

Spring Boot Reference Guide

13. Build systems

It is strongly recommended that you choose a build system that supports

dependency management

,

and one that can consume artifacts published to the “Maven Central” repository. We would recommend that you choose Maven or Gradle. It is possible to get Spring Boot to work with other build systems (Ant for example), but they will not be particularly well supported.

13.1 Dependency management

Each release of Spring Boot provides a curated list of dependencies it supports. In practice, you do not need to provide a version for any of these dependencies in your build configuration as Spring Boot is managing that for you. When you upgrade Spring Boot itself, these dependencies will be upgraded as well in a consistent way.

Note

You can still specify a version and override Spring Boot’s recommendations if you feel that’s necessary.

The curated list contains all the spring modules that you can use with Spring Boot as well as a refined list of third party libraries. The list is available as a standard

Bills of Materials ( spring-bootdependencies

) and additional dedicated support for

Maven and

Gradle

are available as well.

Warning

Each release of Spring Boot is associated with a base version of the Spring Framework so we

highly recommend you to not specify its version on your own.

13.2 Maven

Maven users can inherit from the spring-boot-starter-parent

project to obtain sensible defaults.

The parent project provides the following features:

• Java 1.6 as the default compiler level.

• UTF-8 source encoding.

• A

Dependency Management section

, allowing you to omit

<version>

tags for common dependencies, inherited from the spring-boot-dependencies

POM.

• Sensible resource filtering .

• Sensible plugin configuration ( exec plugin , surefire , Git commit ID , shade ).

• Sensible resource filtering for application.properties

and application.yml

On the last point: since the default config files accept Spring style placeholders (

${…}

) the Maven filtering is changed to use

@[email protected]

placeholders (you can override that with a Maven property resource.delimiter

).

Inheriting the starter parent

To configure your project to inherit from the spring-boot-starter-parent

simply set the parent

:

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<!-- Inherit defaults from Spring Boot -->

<parent>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter-parent

</artifactId>

<version>

1.3.1.BUILD-SNAPSHOT

</version>

</parent>

Note

You should only need to specify the Spring Boot version number on this dependency. If you import additional starters, you can safely omit the version number.

With that setup, you can also override individual dependencies by overriding a property in your own project. For instance, to upgrade to another Spring Data release train you’d add the following to your pom.xml

.

<properties>

<spring-data-releasetrain.version>

Fowler-SR2

</spring-data-releasetrain.version>

</properties>

Tip

Check the spring-boot-dependencies

pom for a list of supported properties.

Using Spring Boot without the parent POM

Not everyone likes inheriting from the spring-boot-starter-parent

POM. You may have your own corporate standard parent that you need to use, or you may just prefer to explicitly declare all your

Maven configuration.

If you don’t want to use the spring-boot-starter-parent

, you can still keep the benefit of the dependency management (but not the plugin management) by using a scope=import

dependency:

<dependencyManagement>

<dependencies>

<dependency>

<!-- Import dependency management from Spring Boot -->

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-dependencies

</artifactId>

<version>

1.3.1.BUILD-SNAPSHOT

</version>

<type>

pom

</type>

<scope>

import

</scope>

</dependency>

</dependencies>

</dependencyManagement>

That setup does not allow you to override individual dependencies using a property as explained above.

To achieve the same result, you’d need to add an entry in the dependencyManagement

of your project

before the spring-boot-dependencies

entry. For instance, to upgrade to another Spring Data release train you’d add the following to your pom.xml

.

<dependencyManagement>

<dependencies>

<!-- Override Spring Data release train provided by Spring Boot -->

<dependency>

<groupId>

org.springframework.data

</groupId>

<artifactId>

spring-data-releasetrain

</artifactId>

<version>

Fowler-SR2

</version>

<scope>

import

</scope>

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<type>

pom

</type>

</dependency>

<dependency>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-dependencies

</artifactId>

<version>

1.3.1.BUILD-SNAPSHOT

</version>

<type>

pom

</type>

<scope>

import

</scope>

</dependency>

</dependencies>

</dependencyManagement>

Note

In the example above, we specify a BOM but any dependency type can be overridden that way.

Changing the Java version

The spring-boot-starter-parent

chooses fairly conservative Java compatibility. If you want to follow our recommendation and use a later Java version you can add a java.version

property:

<properties>

<java.version>

1.8

</java.version>

</properties>

Using the Spring Boot Maven plugin

Spring Boot includes a

Maven plugin that can package the project as an executable jar. Add the plugin

to your

<plugins>

section if you want to use it:

<build>

<plugins>

<plugin>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-maven-plugin

</artifactId>

</plugin>

</plugins>

</build>

Note

If you use the Spring Boot starter parent pom, you only need to add the plugin, there is no need for to configure it unless you want to change the settings defined in the parent.

13.3 Gradle

Gradle users can directly import “starter POMs” in their dependencies

section. Unlike Maven, there is no “super parent” to import to share some configuration.

apply plugin:

'java'

repositories {

maven { url

"http://repo.spring.io/snapshot"

}

maven { url

"http://repo.spring.io/milestone"

}

} dependencies {

compile(

"org.springframework.boot:spring-boot-starter-web:1.3.1.BUILD-SNAPSHOT"

)

}

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The

spring-boot-gradle-plugin

is also available and provides tasks to create executable jars

and run projects from source. It also provides dependency management

that, among other capabilities, allows you to omit the version number for any dependencies that are managed by Spring Boot: buildscript {

repositories {

maven { url

"http://repo.spring.io/snapshot"

}

maven { url

"http://repo.spring.io/milestone"

}

}

dependencies {

classpath(

"org.springframework.boot:spring-boot-gradle-plugin:1.3.1.BUILD-SNAPSHOT"

)

}

} apply plugin:

'java'

apply plugin:

'spring-boot'

repositories {

maven { url

"http://repo.spring.io/snapshot"

}

maven { url

"http://repo.spring.io/milestone"

}

} dependencies {

compile(

"org.springframework.boot:spring-boot-starter-web"

)

testCompile(

"org.springframework.boot:spring-boot-starter-test"

)

}

13.4 Ant

It is possible to build a Spring Boot project using Apache Ant+Ivy. The spring-boot-antlib

“AntLib” module is also available to help Ant create executable jars.

To declare dependencies a typical ivy.xml

file will look something like this:

<ivy-module version

=

"2.0" >

<info organisation

=

"org.springframework.boot" module

=

"spring-boot-sample-ant" />

<configurations>

<conf name

=

"compile" description

=

"everything needed to compile this module" />

<conf name

=

"runtime" extends

=

"compile" description

=

"everything needed to run this module" />

</configurations>

<dependencies>

<dependency org

=

"org.springframework.boot" name

=

"spring-boot-starter" rev

=

"${spring-boot.version}" conf

=

"compile" />

</dependencies>

</ivy-module>

A typical build.xml

will look like this:

<project xmlns:ivy

=

"antlib:org.apache.ivy.ant" xmlns:spring-boot

=

"antlib:org.springframework.boot.ant" name

=

"myapp" default

=

"build" >

<property name

=

"spring-boot.version" value

=

"1.3.0.BUILD-SNAPSHOT" />

<target name

=

"resolve" description

=

"--> retrieve dependencies with ivy" >

<ivy:retrieve pattern

=

"lib/[conf]/[artifact]-[type]-[revision].[ext]" />

</target>

<target name

=

"classpaths" depends

=

"resolve" >

<path id

=

"compile.classpath" >

<fileset dir

=

"lib/compile" includes

=

"*.jar" />

</path>

</target>

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<target name

=

"init" depends

=

"classpaths" >

<mkdir dir

=

"build/classes" />

</target>

<target name

=

"compile" depends

=

"init" description

=

"compile" >

<javac srcdir

=

"src/main/java" destdir

=

"build/classes" classpathref

=

"compile.classpath" />

</target>

<target name

=

"build" depends

=

"compile" >

<spring-boot:exejar destfile

=

"build/myapp.jar" classes

=

"build/classes" >

<spring-boot:lib>

<fileset dir

=

"lib/runtime" />

</spring-boot:lib>

</spring-boot:exejar>

</target>

</project>

Tip

See the

Section 79.8, “Build an executable archive from Ant without using spring-boot-antlib”

“How-to” if you don’t want to use the spring-boot-antlib

module.

13.5 Starter POMs

Starter POMs are a set of convenient dependency descriptors that you can include in your application.

You get a one-stop-shop for all the Spring and related technology that you need, without having to hunt through sample code and copy paste loads of dependency descriptors. For example, if you want to get started using Spring and JPA for database access, just include the spring-boot-starter-datajpa

dependency in your project, and you are good to go.

The starters contain a lot of the dependencies that you need to get a project up and running quickly and with a consistent, supported set of managed transitive dependencies.

What’s in a name

All official starters follow a similar naming pattern; spring-boot-starter-*

, where

*

is a particular type of application. This naming structure is intended to help when you need to find a starter. The Maven integration in many IDEs allow you to search dependencies by name. For example, with the appropriate Eclipse or STS plugin installed, you can simply hit ctrl-space

in the POM editor and type “spring-boot-starter” for a complete list.

As explained in the

Creating your own starter

section, third party starters should not start with spring-boot

as it is reserved for official Spring Boot artifacts. A third-party starter for acme

will be typically named acme-spring-boot-starter

.

The following application starters are provided by Spring Boot under the org.springframework.boot

group:

Table 13.1. Spring Boot application starters

Name

spring-boot-starter spring-boot-starter-actuator

Description

The core Spring Boot starter, including autoconfiguration support, logging and YAML.

Production ready features to help you monitor and manage your application.

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Name

spring-boot-starter-amqp spring-boot-starter-aop spring-boot-starter-artemis

Description

Support for the “Advanced Message Queuing

Protocol” via spring-rabbit

.

Support for aspect-oriented programming including spring-aop

and AspectJ.

Support for “Java Message Service API” via

Apache Artemis.

spring-boot-starter-batch spring-boot-starter-cache

Support for “Spring Batch” including HSQLDB database.

Support for Spring’s Cache abstraction.

spring-boot-starter-cloud-connectors

Support for “Spring Cloud Connectors” which simplifies connecting to services in cloud platforms like Cloud Foundry and Heroku.

spring-boot-starter-dataelasticsearch spring-boot-starter-data-gemfire

Support for the Elasticsearch search and analytics engine including spring-dataelasticsearch

.

Support for the GemFire distributed data store including spring-data-gemfire

.

spring-boot-starter-data-jpa spring-boot-starter-data-mongodb

Support for the “Java Persistence API” including spring-data-jpa

, spring-orm

and

Hibernate.

Support for the MongoDB NoSQL Database, including spring-data-mongodb

.

spring-boot-starter-data-rest spring-boot-starter-data-solr

Support for exposing Spring Data repositories over REST via spring-data-rest-webmvc

.

Support for the Apache Solr search platform, including spring-data-solr

.

spring-boot-starter-freemarker

Support for the FreeMarker templating engine.

spring-boot-starter-groovy-templates

Support for the Groovy templating engine.

spring-boot-starter-hateoas spring-boot-starter-hornetq spring-boot-starter-integration

Support for HATEOAS-based RESTful services via spring-hateoas

.

Support for “Java Message Service API” via

HornetQ.

Support for common spring-integration modules.

spring-boot-starter-jdbc spring-boot-starter-jersey

Support for JDBC databases.

Support for the Jersey RESTful Web Services framework.

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Name

spring-boot-starter-jta-atomikos spring-boot-starter-jta-bitronix spring-boot-starter-mail

Description

Support for JTA distributed transactions via

Atomikos.

Support for JTA distributed transactions via

Bitronix.

Support for javax.mail

.

spring-boot-starter-mobile spring-boot-starter-mustache spring-boot-starter-redis

Support for spring-mobile

.

Support for the Mustache templating engine.

Support for the REDIS key-value data store, including spring-redis

.

spring-boot-starter-security

Support for spring-security

.

spring-boot-starter-social-facebook

Support for spring-social-facebook

.

spring-boot-starter-social-linkedin

Support for spring-social-linkedin

.

spring-boot-starter-social-twitter

Support for spring-social-twitter

.

spring-boot-starter-test spring-boot-starter-thymeleaf spring-boot-starter-velocity spring-boot-starter-web spring-boot-starter-websocket spring-boot-starter-ws

Support for common test dependencies, including JUnit, Hamcrest and Mockito along with the spring-test

module.

Support for the Thymeleaf templating engine, including integration with Spring.

Support for the Velocity templating engine.

Support for full-stack web development, including Tomcat and spring-webmvc

.

Support for WebSocket development.

Support for Spring Web Services.

In addition to the application starters, the following starters can be used to add

production ready

features.

Table 13.2. Spring Boot production ready starters

Name

spring-boot-starter-actuator spring-boot-starter-remote-shell

Description

Adds production ready features such as metrics and monitoring.

Adds remote ssh

shell support.

Finally, Spring Boot includes some starters that can be used if you want to exclude or swap specific technical facets.

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Table 13.3. Spring Boot technical starters

Name

spring-boot-starter-jetty spring-boot-starter-log4j spring-boot-starter-logging spring-boot-starter-tomcat spring-boot-starter-undertow

Description

Imports the Jetty HTTP engine (to be used as an alternative to Tomcat).

Support the Log4J logging framework.

Import Spring Boot’s default logging framework

(Logback).

Import Spring Boot’s default HTTP engine

(Tomcat).

Imports the Undertow HTTP engine (to be used as an alternative to Tomcat).

Tip

For a list of additional community contributed starter POMs, see the README file in the springboot-starters

module on GitHub.

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14. Structuring your code

Spring Boot does not require any specific code layout to work, however, there are some best practices that help.

14.1 Using the “default” package

When a class doesn’t include a package

declaration it is considered to be in the “default package”.

The use of the “default package” is generally discouraged, and should be avoided. It can cause particular problems for Spring Boot applications that use

@ComponentScan

,

@EntityScan

or

@SpringBootApplication

annotations, since every class from every jar, will be read.

Tip

We recommend that you follow Java’s recommended package naming conventions and use a reversed domain name (for example, com.example.project

).

14.2 Locating the main application class

We generally recommend that you locate your main application class in a root package above other classes. The

@EnableAutoConfiguration

annotation is often placed on your main class, and it implicitly defines a base “search package” for certain items. For example, if you are writing a JPA application, the package of the

@EnableAutoConfiguration

annotated class will be used to search for

@Entity

items.

Using a root package also allows the

@ComponentScan

annotation to be used without needing to specify a basePackage

attribute. You can also use the

@SpringBootApplication

annotation if your main class is in the root package.

Here is a typical layout: com

+- example

+- myproject

+- Application.java

|

+- domain

| +- Customer.java

| +- CustomerRepository.java

|

+- service

| +- CustomerService.java

|

+- web

+- CustomerController.java

The

Application.java

file would declare the main

method, along with the basic

@Configuration

.

package

com.example.myproject;

import

org.springframework.boot.SpringApplication;

import

org.springframework.boot.autoconfigure.EnableAutoConfiguration;

import

org.springframework.context.annotation.ComponentScan;

import

org.springframework.context.annotation.Configuration;

@Configuration

@EnableAutoConfiguration

@ComponentScan

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public class

Application {

public static void

main(String[] args) {

SpringApplication.run(Application.

class

, args);

}

}

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15. Configuration classes

Spring Boot favors Java-based configuration. Although it is possible to call

SpringApplication.run()

with an XML source, we generally recommend that your primary source is a

@Configuration

class. Usually the class that defines the main

method is also a good candidate as the primary

@Configuration

.

Tip

Many Spring configuration examples have been published on the Internet that use XML configuration. Always try to use the equivalent Java-based configuration if possible. Searching for enable*

annotations can be a good starting point.

15.1 Importing additional configuration classes

You don’t need to put all your

@Configuration

into a single class. The

@Import

annotation can be used to import additional configuration classes. Alternatively, you can use

@ComponentScan

to automatically pick up all Spring components, including

@Configuration

classes.

15.2 Importing XML configuration

If you absolutely must use XML based configuration, we recommend that you still start with a

@Configuration

class. You can then use an additional

@ImportResource

annotation to load XML configuration files.

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16. Auto-configuration

Spring Boot auto-configuration attempts to automatically configure your Spring application based on the jar dependencies that you have added. For example, If

HSQLDB

is on your classpath, and you have not manually configured any database connection beans, then we will auto-configure an in-memory database.

You need to opt-in to auto-configuration by adding the

@EnableAutoConfiguration

or

@SpringBootApplication

annotations to one of your

@Configuration

classes.

Tip

You should only ever add one

@EnableAutoConfiguration

annotation. We generally recommend that you add it to your primary

@Configuration

class.

16.1 Gradually replacing auto-configuration

Auto-configuration is noninvasive, at any point you can start to define your own configuration to replace specific parts of the auto-configuration. For example, if you add your own

DataSource

bean, the default embedded database support will back away.

If you need to find out what auto-configuration is currently being applied, and why, start your application with the

--debug

switch. This will log an auto-configuration report to the console.

16.2 Disabling specific auto-configuration

If you find that specific auto-configure classes are being applied that you don’t want, you can use the exclude attribute of

@EnableAutoConfiguration

to disable them.

import

org.springframework.boot.autoconfigure.*;

import

org.springframework.boot.autoconfigure.jdbc.*;

import

org.springframework.context.annotation.*;

@Configuration

@EnableAutoConfiguration(exclude={DataSourceAutoConfiguration.class})

public class

MyConfiguration {

}

If the class is not on the classpath, you can use the excludeName

attribute of the annotation and specify the fully qualified name instead. Finally, you can also control the list of auto-configuration classes to exclude via the spring.autoconfigure.exclude

property.

Tip

You can define exclusions both at the annotation level and using the property.

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17. Spring Beans and dependency injection

You are free to use any of the standard Spring Framework techniques to define your beans and their injected dependencies. For simplicity, we often find that using

@ComponentScan

to find your beans, in combination with

@Autowired

constructor injection works well.

If you structure your code as suggested above (locating your application class in a root package), you can add

@ComponentScan

without any arguments. All of your application components (

@Component

,

@Service

,

@Repository

,

@Controller

etc.) will be automatically registered as Spring Beans.

Here is an example

@Service

Bean that uses constructor injection to obtain a required

RiskAssessor bean.

package

com.example.service;

import

org.springframework.beans.factory.annotation.Autowired;

import

org.springframework.stereotype.Service;

@Service

public class

DatabaseAccountService

implements

AccountService {

private final

RiskAssessor riskAssessor;

@Autowired

public

DatabaseAccountService(RiskAssessor riskAssessor) {

this

.riskAssessor = riskAssessor;

}

// ...

}

Tip

Notice how using constructor injection allows the riskAssessor

field to be marked as final

, indicating that it cannot be subsequently changed.

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18. Using the @SpringBootApplication annotation

Many Spring Boot developers always have their main class annotated with

@Configuration

,

@EnableAutoConfiguration

and

@ComponentScan

. Since these annotations are so frequently used together (especially if you follow the

best practices above), Spring Boot provides a convenient

@SpringBootApplication

alternative.

The

@SpringBootApplication

annotation is equivalent to using

@Configuration

,

@EnableAutoConfiguration

and

@ComponentScan

with their default attributes:

package

com.example.myproject;

import

org.springframework.boot.SpringApplication;

import

org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication

// same as @Configuration @EnableAutoConfiguration @ComponentScan

public class

Application {

public static void

main(String[] args) {

SpringApplication.run(Application.

class

, args);

}

}

Note

@SpringBootApplication

also provides aliases to customize the attributes of

@EnableAutoConfiguration

and

@ComponentScan

.

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19. Running your application

One of the biggest advantages of packaging your application as jar and using an embedded HTTP server is that you can run your application as you would any other. Debugging Spring Boot applications is also easy; you don’t need any special IDE plugins or extensions.

Note

This section only covers jar based packaging, If you choose to package your application as a war file you should refer to your server and IDE documentation.

19.1 Running from an IDE

You can run a Spring Boot application from your IDE as a simple Java application, however, first you will need to import your project. Import steps will vary depending on your IDE and build system. Most

IDEs can import Maven projects directly, for example Eclipse users can select

Import…

Existing

Maven Projects

from the

File

menu.

If you can’t directly import your project into your IDE, you may be able to generate IDE metadata using a build plugin. Maven includes plugins for Eclipse and IDEA ; Gradle offers plugins for various IDEs .

Tip

If you accidentally run a web application twice you will see a “Port already in use” error. STS users can use the

Relaunch

button rather than

Run

to ensure that any existing instance is closed.

19.2 Running as a packaged application

If you use the Spring Boot Maven or Gradle plugins to create an executable jar you can run your application using java -jar

. For example:

$ java -jar target/myproject-0.0.1-SNAPSHOT.jar

It is also possible to run a packaged application with remote debugging support enabled. This allows you to attach a debugger to your packaged application:

$ java -Xdebug -Xrunjdwp:server=y,transport=dt_socket,address=8000,suspend=n \

-jar target/myproject-0.0.1-SNAPSHOT.jar

19.3 Using the Maven plugin

The Spring Boot Maven plugin includes a run

goal which can be used to quickly compile and run your application. Applications run in an exploded form just like in your IDE.

$ mvn spring-boot:run

You might also want to use the useful operating system environment variable:

$ export MAVEN_OPTS=-Xmx1024m -XX:MaxPermSize=128M -Djava.security.egd=file:/dev/./urandom

(The “egd” setting is to speed up Tomcat startup by giving it a faster source of entropy for session keys.)

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19.4 Using the Gradle plugin

The Spring Boot Gradle plugin also includes a bootRun

task which can be used to run your application in an exploded form. The bootRun

task is added whenever you import the spring-boot-gradleplugin

:

$ gradle bootRun

You might also want to use this useful operating system environment variable:

$ export JAVA_OPTS=-Xmx1024m -XX:MaxPermSize=128M -Djava.security.egd=file:/dev/./urandom

19.5 Hot swapping

Since Spring Boot applications are just plain Java applications, JVM hot-swapping should work out of the box. JVM hot swapping is somewhat limited with the bytecode that it can replace, for a more complete solution JRebel or the Spring Loaded project can be used. The spring-boot-devtools

module also includes support for quick application restarts.

See the

Chapter 20, Developer tools section below and the

Hot swapping “How-to” for details.

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20. Developer tools

Spring Boot includes an additional set of tools that can make the application development experience a little more pleasant. The spring-boot-devtools

module can be included in any project to provide additional development-time features. To include devtools support, simply add the module dependency to your build:

Maven.

<dependencies>

<dependency>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-devtools

</artifactId>

<optional>

true

</optional>

</dependency>

</dependencies>

Gradle.

dependencies {

compile(

"org.springframework.boot:spring-boot-devtools"

)

}

Note

Developer tools are automatically disabled when running a fully packaged application. If your application is launched using java -jar

or if it’s started using a special classloader, then it is considered a “production application”. Flagging the dependency as optional is a best practice that prevents devtools from being transitively applied to other modules using your project. Gradle does not support optional

dependencies out-of-the-box so you may want to have a look to the propdeps-plugin

in the meantime.

Tip

If you want to ensure that devtools is never included in a production build, you can use the excludeDevtools

build property to completely remove the JAR. The property is supported with both the Maven and Gradle plugins.

20.1 Property defaults

Several of the libraries supported by Spring Boot use caches to improve performance. For example,

Thymeleaf will cache templates to save repeatedly parsing XML source files. Whilst caching is very beneficial in production, it can be counter productive during development. If you make a change to a template file in your IDE, you’ll likely want to immediately see the result.

Cache options are usually configured by settings in your application.properties

file. For example, Thymeleaf offers the spring.thymeleaf.cache

property. Rather than needing to set these properties manually, the spring-boot-devtools

module will automatically apply sensible development-time configuration.

Tip

For a complete list of the properties that are applied see DevToolsPropertyDefaultsPostProcessor .

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20.2 Automatic restart

Applications that use spring-boot-devtools

will automatically restart whenever files on the classpath change. This can be a useful feature when working in an IDE as it gives a very fast feedback loop for code changes. By default, any entry on the classpath that points to a folder will be monitored for changes.

Triggering a restart

As DevTools monitors classpath resources, the only way to trigger a restart is to update the classpath. The way in which you cause the classpath to be updated depends on the IDE that you are using. In Eclipse, saving a modified file will cause the classpath to be updated and trigger a restart. In IntelliJ IDEA, building the project (

Build # Make Project

) will have the same effect.

Note

You can also start your application via the supported build plugins (i.e. Maven and Gradle) as long as forking is enabled since DevTools need an isolated application classloader to operate properly.

You can force the plugin to fork the process as follows:

Maven.

<build>

<plugins>

<plugin>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-maven-plugin

</artifactId>

<configuration>

<fork>

true

</fork>

</configuration>

</plugin>

</plugins>

</build>

Gradle.

bootRun {

addResources = true

}

Tip

Automatic restart works very well when used with LiveReload.

See below

for details. If you use

JRebel automatic restarts will be disabled in favor of dynamic class reloading. Other devtools features (such as LiveReload and property overrides) can still be used.

Note

DevTools relies on the application context’s shutdown hook to close it during a restart. It will not work correctly if you have disabled the shutdown hook (

SpringApplication.setRegisterShutdownHook(false)

).

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Note

When deciding if an entry on the classpath should trigger a restart when it changes, DevTools automatically ignores projects named spring-boot

, spring-boot-devtools

, springboot-autoconfigure

, spring-boot-actuator

, and spring-boot-starter

.

Restart vs Reload

The restart technology provided by Spring Boot works by using two classloaders. Classes that don’t change (for example, those from third-party jars) are loaded into a base classloader. Classes that you’re actively developing are loaded into a restart classloader. When the application is restarted, the restart classloader is thrown away and a new one is created. This approach means that application restarts are typically much faster than “cold starts” since the base classloader is already available and populated.

If you find that restarts aren’t quick enough for your applications, or you encounter classloading issues, you could consider reloading technologies such as JRebel from ZeroTurnaround. These work by rewriting classes as they are loaded to make them more amenable to reloading. Spring

Loaded provides another option, however it doesn’t support as many frameworks and it isn’t commercially supported.

Excluding resources

Certain resources don’t necessarily need to trigger a restart when they are changed. For example,

Thymeleaf templates can just be edited in-place. By default changing resources in

/META-INF/ maven

,

/META-INF/resources

,

/resources

,

/static

,

/public

or

/templates

will not trigger a restart but will trigger a

live reload . If you want to customize these exclusions you can use the

spring.devtools.restart.exclude

property. For example, to exclude only

/static

and

/ public

you would set the following: spring.devtools.restart.exclude=static/**,public/**

Tip

if you want to keep those defaults and add additional exclusions, use the spring.devtools.restart.additional-exclude

property instead.

Watching additional paths

You may want your application to be restarted or reloaded when you make changes to files that are not on the classpath. To do so, use the spring.devtools.restart.additionalpaths

property to configure additional paths to watch for changes. You can use the spring.devtools.restart.exclude

property

described above to control whether changes

beneath the additional paths will trigger a full restart or just a live reload .

Disabling restart

If you don’t want to use the restart feature you can disable it using the spring.devtools.restart.enabled

property. In most cases you can set this in your application.properties

(this will still initialize the restart classloader but it won’t watch for file changes).

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If you need to completely disable restart support, for example, because it doesn’t work with a specific library, you need to set a

System

property before calling

SpringApplication.run(…)

. For example:

public static void

main(String[] args) {

System.setProperty(

"spring.devtools.restart.enabled"

,

"false"

);

SpringApplication.run(MyApp.

class

, args);

}

Using a trigger file

If you work with an IDE that continuously compiles changed files, you might prefer to trigger restarts only at specific times. To do this you can use a “trigger file”, which is a special file that must be modified when you want to actually trigger a restart check. The trigger file could be updated manually, or via an IDE plugin.

To use a trigger file use the spring.devtools.restart.trigger-file

property.

Tip

You might want to set spring.devtools.restart.trigger-file

as a global setting so that

all your projects behave in the same way.

Customizing the restart classloader

As described in the

Restart vs Reload section above, restart functionality is implemented by using

two classloaders. For most applications this approach works well, however, sometimes it can cause classloading issues.

By default, any open project in your IDE will be loaded using the “restart” classloader, and any regular

.jar

file will be loaded using the “base” classloader. If you work on a multi-module project, and not each module is imported into your IDE, you may need to customize things. To do this you can create a

META-INF/spring-devtools.properties

file.

The spring-devtools.properties

file can contain restart.exclude.

and restart.include.

prefixed properties. The include

elements are items that should be pulled up into the “restart” classloader, and the exclude

elements are items that should be pushed down into the “base” classloader. The value of the property is a regex pattern that will be applied to the classpath.

For example:

restart.include.companycommonlibs

=/mycorp-common-[\\w-]+\.jar

restart.include.projectcommon

=/mycorp-myproj-[\\w-]+\.jar

Note

All property keys must be unique. As long as a property starts with restart.include.

or restart.exclude.

it will be considered.

Tip

All

META-INF/spring-devtools.properties

from the classpath will be loaded. You can package files inside your project, or in the libraries that the project consumes.

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Known limitations

Restart functionality does not work well with objects that are deserialized using a standard

ObjectInputStream

. If you need to deserialize data, you may need to use Spring’s

ConfigurableObjectInputStream

in combination with

Thread.currentThread().getContextClassLoader()

.

Unfortunately, several third-party libraries deserialize without considering the context classloader. If you find such a problem, you will need to request a fix with the original authors.

20.3 LiveReload

The spring-boot-devtools

module includes an embedded LiveReload server that can be used to trigger a browser refresh when a resource is changed. LiveReload browser extensions are freely available for Chrome, Firefox and Safari from livereload.com

.

If you don’t want to start the LiveReload server when your application runs you can set the spring.devtools.livereload.enabled

property to false

.

Note

You can only run one LiveReload server at a time, if you start multiple applications from your IDE only the first will have livereload support.

20.4 Global settings

You can configure global devtools settings by adding a file named

.spring-bootdevtools.properties

to your

$HOME

folder (note that the filename starts with “.”). Any properties added to this file will apply to all Spring Boot applications on your machine that use devtools. For example, to configure restart to always use a

trigger file , you would add the following:

~/.spring-boot-devtools.properties. spring.devtools.reload.trigger-file

=.reloadtrigger

20.5 Remote applications

The Spring Boot developer tools are not just limited to local development. You can also use several features when running applications remotely. Remote support is opt-in, to enable it you need to set a spring.devtools.remote.secret

property. For example:

spring.devtools.remote.secret

=mysecret

Warning

Enabling spring-boot-devtools

on a remote application is a security risk. You should never enable support on a production deployment.

Remote devtools support is provided in two parts; there is a server side endpoint that accepts connections, and a client application that you run in your IDE. The server component is automatically enabled when the spring.devtools.remote.secret

property is set. The client component must be launched manually.

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Running the remote client application

The remote client application is designed to be run from within you IDE. You need to run org.springframework.boot.devtools.RemoteSpringApplication

using the same classpath as the remote project that you’re connecting to. The non-option argument passed to the application should be the remote URL that you are connecting to.

For example, if you are using Eclipse or STS, and you have a project named my-app

that you’ve deployed to Cloud Foundry, you would do the following:

• Select

Run Configurations…

from the

Run

menu.

• Create a new

Java Application

“launch configuration”.

• Browse for the my-app

project.

• Use org.springframework.boot.devtools.RemoteSpringApplication

as the main class.

• Add https://myapp.cfapps.io

to the

Program arguments

(or whatever your remote URL is).

A running remote client will look like this:

. ____ _ __ _ _

/\\ / ___'_ __ _ _(_)_ __ __ _ ___ _ \ \ \ \

( ( )\___ | '_ | '_| | '_ \/ _` | | _ \___ _ __ ___| |_ ___ \ \ \ \

\\/ ___)| |_)| | | | | || (_| []::::::[] / -_) ' \/ _ \ _/ -_) ) ) ) )

' |____| .__|_| |_|_| |_\__, | |_|_\___|_|_|_\___/\__\___|/ / / /

=========|_|==============|___/===================================/_/_/_/

:: Spring Boot Remote :: 1.3.1.BUILD-SNAPSHOT

2015-06-10 18:25:06.632 INFO 14938 --- [ main] o.s.b.devtools.RemoteSpringApplication :

Starting RemoteSpringApplication on pwmbp with PID 14938 (/Users/pwebb/projects/spring-boot/code/ spring-boot-devtools/target/classes started by pwebb in /Users/pwebb/projects/spring-boot/code/springboot-samples/spring-boot-sample-devtools)

2015-06-10 18:25:06.671 INFO 14938 --- [ main] s.c.a.AnnotationConfigApplicationContext :

Refreshing org.spring[email protected]2a17b7b6: startup

date [Wed Jun 10 18:25:06 PDT 2015]; root of context hierarchy

2015-06-10 18:25:07.043 WARN 14938 --- [ main] o.s.b.d.r.c.RemoteClientConfiguration : The

connection to http://localhost:8080 is insecure. You should use a URL starting with 'https://'.

2015-06-10 18:25:07.074 INFO 14938 --- [ main] o.s.b.d.a.OptionalLiveReloadServer :

LiveReload server is running on port 35729

2015-06-10 18:25:07.130 INFO 14938 --- [ main] o.s.b.devtools.RemoteSpringApplication :

Started RemoteSpringApplication in 0.74 seconds (JVM running for 1.105)

Note

Because the remote client is using the same classpath as the real application it can directly read application properties. This is how the spring.devtools.remote.secret

property is read and passed to the server for authentication.

Tip

It’s always advisable to use https://

as the connection protocol so that traffic is encrypted and passwords cannot be intercepted.

Tip

If you need to use a proxy to access the remote application, configure the spring.devtools.remote.proxy.host

and spring.devtools.remote.proxy.port

properties.

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Remote update

The remote client will monitor your application classpath for changes in the same way as the local restart .

Any updated resource will be pushed to the remote application and (if required) trigger a restart. This can be quite helpful if you are iterating on a feature that uses a cloud service that you don’t have locally.

Generally remote updates and restarts are much quicker than a full rebuild and deploy cycle.

Note

Files are only monitored when the remote client is running. If you change a file before starting the remote client, it won’t be pushed to the remote server.

Remote debug tunnel

Java remote debugging is useful when diagnosing issues on a remote application. Unfortunately, it’s not always possible to enable remote debugging when your application is deployed outside of your data center. Remote debugging can also be tricky to setup if you are using a container based technology such as Docker.

To help work around these limitations, devtools supports tunneling of remote debug traffic over HTTP.

The remote client provides a local server on port

8000

that you can attach a remote debugger to. Once a connection is established, debug traffic is sent over HTTP to the remote application. You can use the spring.devtools.remote.debug.local-port

property if you want to use a different port.

You’ll need to ensure that your remote application is started with remote debugging enabled. Often this can be achieved by configuring

JAVA_OPTS

. For example, with Cloud Foundry you can add the following to your manifest.yml

:

---

env

:

JAVA_OPTS

:

"-Xdebug -Xrunjdwp:server=y,transport=dt_socket,suspend=n"

Tip

Notice that you don’t need to pass an address=NNNN

option to

-Xrunjdwp

. If omitted Java will simply pick a random free port.

Note

Debugging a remote service over the Internet can be slow and you might need to increase timeouts in your IDE. For example, in Eclipse you can select

Java

Debug

from

Preferences…

and change the

Debugger timeout (ms)

to a more suitable value (

60000

works well in most situations).

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21. Packaging your application for production

Executable jars can be used for production deployment. As they are self-contained, they are also ideally suited for cloud-based deployment.

For additional “production ready” features, such as health, auditing and metric REST or JMX endpoints; consider adding spring-boot-actuator

. See

Part V, “Spring Boot Actuator: Productionready features”

for details.

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22. What to read next

You should now have good understanding of how you can use Spring Boot along with some best practices that you should follow. You can now go on to learn about specific

Spring Boot features

in

depth, or you could skip ahead and read about the “

production ready

” aspects of Spring Boot.

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Part IV. Spring Boot features

This section dives into the details of Spring Boot. Here you can learn about the key features that you will want to use and customize. If you haven’t already, you might want to read the

Part II, “Getting started”

and

Part III, “Using Spring Boot”

sections so that you have a good grounding of the basics.

Spring Boot Reference Guide

23. SpringApplication

The

SpringApplication

class provides a convenient way to bootstrap a Spring application that will be started from a main()

method. In many situations you can just delegate to the static

SpringApplication.run

method:

public static void

main(String[] args) {

SpringApplication.run(MySpringConfiguration.

class

, args);

}

When your application starts you should see something similar to the following:

. ____ _ __ _ _

/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \

( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \

\\/ ___)| |_)| | | | | || (_| | ) ) ) )

' |____| .__|_| |_|_| |_\__, | / / / /

=========|_|==============|___/=/_/_/_/

:: Spring Boot :: v1.3.1.BUILD-SNAPSHOT

2013-07-31 00:08:16.117 INFO 56603 --- [ main] o.s.b.s.app.SampleApplication :

Starting SampleApplication v0.1.0 on mycomputer with PID 56603 (/apps/myapp.jar started by pwebb)

2013-07-31 00:08:16.166 INFO 56603 --- [ main] ationConfigEmbeddedWebApplicationContext :

Refreshing

org.springframework.boot[email protected]6e5a8246:

startup date [Wed Jul 31 00:08:16 PDT 2013]; root of context hierarchy

2014-03-04 13:09:54.912 INFO 41370 --- [ main] .t.TomcatEmbeddedServletContainerFactory :

Server initialized with port: 8080

2014-03-04 13:09:56.501 INFO 41370 --- [ main] o.s.b.s.app.SampleApplication :

Started SampleApplication in 2.992 seconds (JVM running for 3.658)

By default

INFO

logging messages will be shown, including some relevant startup details such as the user that launched the application.

23.1 Customizing the Banner

The banner that is printed on start up can be changed by adding a banner.txt

file to your classpath, or by setting banner.location

to the location of such a file. If the file has an unusual encoding you can set banner.charset

(default is

UTF-8

).

You can use the following variables inside your banner.txt

file:

Table 23.1. Banner variables

Variable

${application.version}

${application.formatted-version}

${spring-boot.version}

Description

The version number of your application as declared in

MANIFEST.MF

. For example

Implementation-Version: 1.0

is printed as

1.0

.

The version number of your application as declared in

MANIFEST.MF

formatted for display

(surrounded with brackets and prefixed with v

).

For example

(v1.0)

.

The Spring Boot version that you are using. For example

1.3.1.BUILD-SNAPSHOT

.

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Variable

${spring-boot.formatted-version}

Description

The Spring Boot version that you are using formatted for display (surrounded with brackets and prefixed with v

). For example

(v1.3.1.BUILD-SNAPSHOT)

.

Where

NAME

is the name of an ANSI escape code. See

AnsiPropertySource

for details.

${Ansi.NAME}

(or

${AnsiColor.NAME}

,

${AnsiBackground.NAME}

,

${AnsiStyle.NAME}

)

${application.title}

The title of your application as declared in

MANIFEST.MF

. For example

Implementation-Title: MyApp

is printed as

MyApp

.

Tip

The

SpringApplication.setBanner(…)

method can be used if you want to generate a banner programmatically. Use the org.springframework.boot.Banner

interface and implement your own printBanner()

method.

You can also use the spring.main.banner-mode

property to determine if the banner has to be printed on

System.out

( console

), using the configured logger ( log

) or not at all ( off

).

Note

YAML maps off

to false

so make sure to add quotes if you want to disable the banner in your application.

spring

:

main

:

banner-mode

:

"off"

23.2 Customizing SpringApplication

If the

SpringApplication

defaults aren’t to your taste you can instead create a local instance and customize it. For example, to turn off the banner you would write:

public static void

main(String[] args) {

SpringApplication app =

new

SpringApplication(MySpringConfiguration.

class

);

app.setBannerMode(Banner.Mode.OFF);

app.run(args);

}

Note

The constructor arguments passed to

SpringApplication

are configuration sources for spring beans. In most cases these will be references to

@Configuration

classes, but they could also be references to XML configuration or to packages that should be scanned.

It is also possible to configure the

SpringApplication

using an application.properties

file.

See

Chapter 24, Externalized Configuration

for details.

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For a complete list of the configuration options, see the

SpringApplication

Javadoc .

23.3 Fluent builder API

If you need to build an

ApplicationContext

hierarchy (multiple contexts with a parent/ child relationship), or if you just prefer using a ‘fluent’ builder API, you can use the

SpringApplicationBuilder

.

The

SpringApplicationBuilder

allows you to chain together multiple method calls, and includes parent

and child

methods that allow you to create a hierarchy.

For example:

new

SpringApplicationBuilder()

.bannerMode(Banner.Mode.OFF)

.sources(Parent.

class

)

.child(Application.

class

)

.run(args);

Note

There are some restrictions when creating an

ApplicationContext

hierarchy, e.g. Web components must be contained within the child context, and the same

Environment

will be used for both parent and child contexts. See the

SpringApplicationBuilder

Javadoc for full details.

23.4 Application events and listeners

In addition to the usual Spring Framework events, such as

ContextRefreshedEvent

, a

SpringApplication

sends some additional application events. Some events are actually triggered before the

ApplicationContext

is created.

You can register event listeners in a number of ways, the most common being

SpringApplication.addListeners(…)

method.

Application events are sent in the following order, as your application runs:

1. An

ApplicationStartedEvent

is sent at the start of a run, but before any processing except the registration of listeners and initializers.

2. An

ApplicationEnvironmentPreparedEvent

is sent when the

Environment

to be used in the context is known, but before the context is created.

3. An

ApplicationPreparedEvent

is sent just before the refresh is started, but after bean definitions have been loaded.

4. An

ApplicationReadyEvent

is sent after the refresh and any related callbacks have been processed to indicate the application is ready to service requests.

5. An

ApplicationFailedEvent

is sent if there is an exception on startup.

Tip

You often won’t need to use application events, but it can be handy to know that they exist.

Internally, Spring Boot uses events to handle a variety of tasks.

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23.5 Web environment

A

SpringApplication

will attempt to create the right type of

ApplicationContext on your behalf. By default, an

AnnotationConfigApplicationContext or

AnnotationConfigEmbeddedWebApplicationContext

will be used, depending on whether you are developing a web application or not.

The algorithm used to determine a ‘web environment’ is fairly simplistic (based on the presence of a few classes). You can use setWebEnvironment(boolean webEnvironment)

if you need to override the default.

It is also possible to take complete control of the

ApplicationContext

type that will be used by calling setApplicationContextClass(…)

.

Tip

It is often desirable to call setWebEnvironment(false)

when using

SpringApplication within a JUnit test.

23.6 Accessing application arguments

If you need to access the application arguments that were passed to

SpringApplication.run(…

)

you can inject a org.springframework.boot.ApplicationArguments

bean. The

ApplicationArguments

interface provides access to both the raw

String[]

arguments as well as parsed option

and non-option

arguments:

import

org.springframework.boot.*

import

org.springframework.beans.factory.annotation.*

import

org.springframework.stereotype.*

@Component

public class

MyBean {

@Autowired

public

MyBean(ApplicationArguments args) {

boolean

debug = args.containsOption(

"debug"

);

List<String> files = args.getNonOptionArgs();

// if run with "--debug logfile.txt" debug=true, files=["logfile.txt"]

}

}

Tip

Spring Boot will also register a

CommandLinePropertySource

with the Spring

Environment

.

This allows you to also inject single application arguments using the

@Value

annotation.

23.7 Using the ApplicationRunner or CommandLineRunner

If you need to run some specific code once the

SpringApplication

has started, you can implement the

ApplicationRunner

or

CommandLineRunner

interfaces. Both interfaces work in the same way and offer a single run

method which will be called just before

SpringApplication.run(…) completes.

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The

CommandLineRunner

interfaces provides access to application arguments as a simple string array, whereas the

ApplicationRunner

uses the

ApplicationArguments

interface discussed above.

import

org.springframework.boot.*

import

org.springframework.stereotype.*

@Component

public class

MyBean

implements

CommandLineRunner {

public void

run(String... args) {

// Do something...

}

}

You can additionally implement the org.springframework.core.Ordered

interface or use the org.springframework.core.annotation.Order

annotation if several

CommandLineRunner

or

ApplicationRunner

beans are defined that must be called in a specific order.

23.8 Application exit

Each

SpringApplication

will register a shutdown hook with the JVM to ensure that the

ApplicationContext

is closed gracefully on exit. All the standard Spring lifecycle callbacks (such as the

DisposableBean

interface, or the

@PreDestroy

annotation) can be used.

In addition, beans may implement the org.springframework.boot.ExitCodeGenerator

interface if they wish to return a specific exit code when the application ends.

23.9 Admin features

It is possible to enable admin-related features for the application by specifying the spring.application.admin.enabled

property. This exposes the

SpringApplicationAdminMXBean

on the platform

MBeanServer

. You could use this feature to administer your Spring Boot application remotely. This could also be useful for any service wrapper implementation.

Tip

If you want to know on which HTTP port the application is running, get the property with key local.server.port

.

Note

Take care when enabling this feature as the MBean exposes a method to shutdown the application.

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24. Externalized Configuration

Spring Boot allows you to externalize your configuration so you can work with the same application code in different environments. You can use properties files, YAML files, environment variables and command-line arguments to externalize configuration. Property values can be injected directly into your beans using the

@Value

annotation, accessed via Spring’s

Environment

abstraction or

bound to structured objects

via

@ConfigurationProperties

.

Spring Boot uses a very particular

PropertySource

order that is designed to allow sensible overriding of values, properties are considered in the following order:

1. Command line arguments.

2. Properties from

SPRING_APPLICATION_JSON

(inline JSON embedded in an environment variable or system property)

3. JNDI attributes from java:comp/env

.

4. Java System properties (

System.getProperties()

).

5. OS environment variables.

6. A

RandomValuePropertySource

that only has properties in random.*

.

7.

Profile-specific application properties

outside of your packaged jar ( application-

{profile}.properties

and YAML variants)

8.

Profile-specific application properties

packaged inside your jar ( application-

{profile}.properties

and YAML variants)

9. Application properties outside of your packaged jar ( application.properties

and YAML variants).

10.Application properties packaged inside your jar ( application.properties

and YAML variants).

11.

@PropertySource

annotations on your

@Configuration

classes.

12.Default properties (specified using

SpringApplication.setDefaultProperties

).

To provide a concrete example, suppose you develop a

@Component

that uses a name

property:

import

org.springframework.stereotype.*

import

org.springframework.beans.factory.annotation.*

@Component

public class

MyBean {

@Value("${name}")

private

String name;

// ...

}

On your application classpath (e.g. inside your jar) you can have an application.properties

that provides a sensible default property value for name

. When running in a new environment, an application.properties

can be provided outside of your jar that overrides the name

; and for one-off testing, you can launch with a specific command line switch (e.g. java -jar app.jar -name="Spring"

).

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Tip

The

SPRING_APPLICATION_JSON

properties can be supplied on the command line with an environment variable. For example in a UN*X shell:

$ SPRING_APPLICATION_JSON='{"foo":{"bar":"spam"}}' java -jar myapp.jar

In this example you will end up with foo.bar=spam

in the Spring

Environment

. You can also supply the JSON as spring.application.json

in a System variable:

$ java -Dspring.application.json='{"foo":"bar"}' -jar myapp.jar

or command line argument:

$ java -jar myapp.jar --spring.application.json='{"foo":"bar"}' or as a JNDI variable java:comp/env/spring.application.json

.

24.1 Configuring random values

The

RandomValuePropertySource

is useful for injecting random values (e.g. into secrets or test cases). It can produce integers, longs or strings, e.g.

my.secret

=${random.value}

my.number

=${random.int}

my.bignumber

=${random.long}

my.number.less.than.ten

=${random.int(10)}

my.number.in.range

=${random.int[1024,65536]}

The random.int*

syntax is

OPEN value (,max) CLOSE

where the

OPEN,CLOSE

are any character and value,max

are integers. If max

is provided then value

is the minimum value and max

is the maximum (exclusive).

24.2 Accessing command line properties

By default

SpringApplication

will convert any command line option arguments (starting with ‘--’, e.g.

--server.port=9000

) to a property

and add it to the Spring

Environment

. As mentioned above, command line properties always take precedence over other property sources.

If you don’t want command line properties to be added to the

Environment

you can disable them using

SpringApplication.setAddCommandLineProperties(false)

.

24.3 Application property files

SpringApplication

will load properties from application.properties

files in the following locations and add them to the Spring

Environment

:

1. A

/config

subdirectory of the current directory.

2. The current directory

3. A classpath

/config

package

4. The classpath root

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The list is ordered by precedence (properties defined in locations higher in the list override those defined in lower locations).

Note

You can also use YAML ('.yml') files

as an alternative to '.properties'.

If you don’t like application.properties

as the configuration file name you can switch to another by specifying a spring.config.name

environment property. You can also refer to an explicit location using the spring.config.location

environment property (comma-separated list of directory locations, or file paths).

$ java -jar myproject.jar --spring.config.name=myproject or

$ java -jar myproject.jar --spring.config.location=classpath:/default.properties,classpath:/ override.properties

If spring.config.location

contains directories (as opposed to files) they should end in

/

(and will be appended with the names generated from spring.config.name

before being loaded). The default search path classpath:,classpath:/config,file:,file:config/

is always used, irrespective of the value of spring.config.location

. In that way you can set up default values for your application in application.properties

(or whatever other basename you choose with spring.config.name

) and override it at runtime with a different file, keeping the defaults.

Note

If you use environment variables rather than system properties, most operating systems disallow period-separated key names, but you can use underscores instead (e.g.

SPRING_CONFIG_NAME instead of spring.config.name

).

Note

If you are running in a container then JNDI properties (in java:comp/env

) or servlet context initialization parameters can be used instead of, or as well as, environment variables or system properties.

24.4 Profile-specific properties

In addition to application.properties

files, profile-specific properties can also be defined using the naming convention application-{profile}.properties

. The

Environment

has a set of default profiles (by default

[default]

) which are used if no active profiles are set (i.e. if no profiles are explicitly activated then properties from application-default.properties

are loaded).

Profile-specific properties are loaded from the same locations as standard application.properties

, with profile-specific files always overriding the non-specific ones irrespective of whether the profile-specific files are inside or outside your packaged jar.

If several profiles are specified, a last wins strategy applies. For example, profiles specified by the spring.profiles.active

property are added after those configured via the

SpringApplication

API and therefore take precedence.

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24.5 Placeholders in properties

The values in application.properties

are filtered through the existing

Environment

when they are used so you can refer back to previously defined values (e.g. from System properties).

app.name

=MyApp

app.description

=${app.name} is a Spring Boot application

Tip

You can also use this technique to create ‘short’ variants of existing Spring Boot properties. See

the

Section 69.3, “Use ‘short’ command line arguments”

how-to for details.

24.6 Using YAML instead of Properties

YAML is a superset of JSON, and as such is a very convenient format for specifying hierarchical configuration data. The

SpringApplication

class will automatically support YAML as an alternative to properties whenever you have the SnakeYAML library on your classpath.

Note

If you use ‘starter POMs’ SnakeYAML will be automatically provided via spring-bootstarter

.

Loading YAML

Spring Framework provides two convenient classes that can be used to load YAML documents. The

YamlPropertiesFactoryBean

will load YAML as

Properties

and the

YamlMapFactoryBean

will load YAML as a

Map

.

For example, the following YAML document:

environments

:

dev

:

url

: http://dev.bar.com

name

: Developer Setup

prod

:

url

: http://foo.bar.com

name

: My Cool App

Would be transformed into these properties:

environments.dev.url

=http://dev.bar.com

environments.dev.name

=Developer Setup

environments.prod.url

=http://foo.bar.com

environments.prod.name

=My Cool App

YAML lists are represented as property keys with

[index]

dereferencers, for example this YAML:

my

:

servers

:

- dev.bar.com

- foo.bar.com

Would be transformed into these properties:

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my.servers[0]

=dev.bar.com

my.servers[1]

=foo.bar.com

To bind to properties like that using the Spring

DataBinder

utilities (which is what

@ConfigurationProperties

does) you need to have a property in the target bean of type java.util.List

(or

Set

) and you either need to provide a setter, or initialize it with a mutable value, e.g. this will bind to the properties above

@ConfigurationProperties(prefix="my")

public class

Config {

private

List<String> servers =

new

ArrayList<String>();

public

List<String> getServers() {

return this

.servers;

}

}

Exposing YAML as properties in the Spring Environment

The

YamlPropertySourceLoader

class can be used to expose YAML as a

PropertySource

in the

Spring

Environment

. This allows you to use the familiar

@Value

annotation with placeholders syntax to access YAML properties.

Multi-profile YAML documents

You can specify multiple profile-specific YAML documents in a single file by using a spring.profiles

key to indicate when the document applies. For example:

server

:

address

: 192.168.1.100

---

spring

:

profiles

: development

server

:

address

: 127.0.0.1

---

spring

:

profiles

: production

server

:

address

: 192.168.1.120

In the example above, the server.address

property will be

127.0.0.1

if the development

profile is active. If the development

and production

profiles are not enabled, then the value for the property will be

192.168.1.100

.

The default profiles are activated if none are explicitly active when the application context starts. So in this YAML we set a value for security.user.password

that is only available in the "default" profile:

server

:

port

: 80000

---

spring

:

profiles

: default

security

:

user

:

password

: weak whereas in this example, the password is always set because it isn’t attached to any profile, and it would have to be explicitly reset in all other profiles as necessary:

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server

:

port

: 80000

security

:

user

:

password

: weak

YAML shortcomings

YAML files can’t be loaded via the

@PropertySource

annotation. So in the case that you need to load values that way, you need to use a properties file.

24.7 Type-safe Configuration Properties

Using the

@Value("${property}")

annotation to inject configuration properties can sometimes be cumbersome, especially if you are working with multiple properties or your data is hierarchical in nature.

Spring Boot provides an alternative method of working with properties that allows strongly typed beans to govern and validate the configuration of your application. For example:

@Component

@ConfigurationProperties(prefix="connection")

public class

ConnectionSettings {

private

String username;

private

InetAddress remoteAddress;

// ... getters and setters

}

Note

The getters and setters are advisable, since binding is via standard Java Beans property descriptors, just like in Spring MVC. They are mandatory for immutable types or those that are directly coercible from

String

. As long as they are initialized, maps, collections, and arrays need a getter but not necessarily a setter since they can be mutated by the binder. If there is a setter,

Maps, collections, and arrays can be created. Maps and collections can be expanded with only a getter, whereas arrays require a setter. Nested POJO properties can also be created (so a setter is not mandatory) if they have a default constructor, or a constructor accepting a single value that can be coerced from String. Some people use Project Lombok to add getters and setters automatically.

Note

Contrary to

@Value

, SpEL expressions are not evaluated prior to injecting a value in the relevant

@ConfigurationProperties

bean.

The

@EnableConfigurationProperties

annotation is automatically applied to your project so that any beans annotated with

@ConfigurationProperties

will be configured from the

Environment properties. This style of configuration works particularly well with the

SpringApplication

external

YAML configuration:

# application.yml

connection

:

username

: admin

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remoteAddress

: 192.168.1.1

# additional configuration as required

To work with

@ConfigurationProperties

beans you can just inject them in the same way as any other bean.

@Service

public class

MyService {

@Autowired

private

ConnectionSettings connection;

//...

@PostConstruct

public void

openConnection() {

Server server =

new

Server();

this

.connection.configure(server);

}

}

It is also possible to shortcut the registration of

@ConfigurationProperties

bean definitions by simply listing the properties classes directly in the

@EnableConfigurationProperties

annotation:

@Configuration

@EnableConfigurationProperties(ConnectionSettings.class)

public class

MyConfiguration {

}

Tip

Using

@ConfigurationProperties

also allows you to generate meta-data files that can be used by IDEs. See the

Appendix B, Configuration meta-data appendix for details.

Third-party configuration

As well as using

@ConfigurationProperties

to annotate a class, you can also use it on

@Bean methods. This can be particularly useful when you want to bind properties to third-party components that are outside of your control.

To configure a bean from the

Environment

properties, add

@ConfigurationProperties

to its bean registration:

@ConfigurationProperties(prefix = "foo")

@Bean

public

FooComponent fooComponent() {

...

}

Any property defined with the foo

prefix will be mapped onto that

FooComponent

bean in a similar manner as the

ConnectionSettings

example above.

Relaxed binding

Spring Boot uses some relaxed rules for binding

Environment properties to

@ConfigurationProperties

beans, so there doesn’t need to be an exact match between the

Environment

property name and the bean property name. Common examples where this is useful

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binds to contextPath

), and capitalized (e.g.

PORT binds to port

) environment properties.

For example, given the following

@ConfigurationProperties

class:

@Component

@ConfigurationProperties(prefix="person")

public class

ConnectionSettings {

private

String firstName;

public

String getFirstName() {

return this

.firstName;

}

public void

setFirstName(String firstName) {

this

.firstName = firstName;

}

}

The following properties names can all be used:

Table 24.1. relaxed binding

Property Note

person.firstname

Dashed notation, recommended for use in

.properties

and

.yml

files.

variables.

Properties conversion

Spring will attempt to coerce the external application properties to the right type when it binds to the

@ConfigurationProperties

beans. If you need custom type conversion you can provide a

ConversionService

bean (with bean id conversionService

) or custom property editors (via a

CustomEditorConfigurer

bean) or custom

Converters

(with bean definitions annotated as

@ConfigurationPropertiesBinding

).

Note

As this bean is requested very early during the application lifecycle, make sure to limit the dependencies that your

ConversionService

is using. Typically, any dependency that you require may not be fully initialized at creation time. You may want to rename your custom

ConversionService

if it’s not required for configuration keys coercion and only rely on custom converters qualified with

@ConfigurationPropertiesBinding

.

@ConfigurationProperties Validation

Spring Boot will attempt to validate external configuration, by default using JSR-303 (if it is on the classpath). You can simply add JSR-303 javax.validation

constraint annotations to your

@ConfigurationProperties

class:

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@Component

@ConfigurationProperties(prefix="connection")

public class

ConnectionSettings {

@NotNull

private

InetAddress remoteAddress;

// ... getters and setters

}

In order to validate values of nested properties, you must annotate the associated field as

@Valid

to trigger its validation. For example, building upon the above

ConnectionSettings

example:

@Component

@ConfigurationProperties(prefix="connection")

public class

ConnectionSettings {

@NotNull

@Valid

private

RemoteAddress remoteAddress;

// ... getters and setters

public static class

RemoteAddress {

@NotEmpty

public

String hostname;

// ... getters and setters

}

}

You can also add a custom Spring

Validator

by creating a bean definition called configurationPropertiesValidator

. There is a Validation sample so you can see how to set things up.

Tip

The spring-boot-actuator module includes an endpoint that exposes all

@ConfigurationProperties

beans. Simply point your web browser to

/configprops

or use the equivalent JMX endpoint. See the

Production ready features

. section for details.

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25. Profiles

Spring Profiles provide a way to segregate parts of your application configuration and make it only available in certain environments. Any

@Component

or

@Configuration

can be marked with

@Profile

to limit when it is loaded:

@Configuration

@Profile("production")

public class

ProductionConfiguration {

// ...

}

In the normal Spring way, you can use a spring.profiles.active

Environment

property to specify which profiles are active. You can specify the property in any of the usual ways, for example you could include it in your application.properties

:

spring.profiles.active

=dev,hsqldb or specify on the command line using the switch

--spring.profiles.active=dev,hsqldb

.

25.1 Adding active profiles

The spring.profiles.active

property follows the same ordering rules as other properties, the highest

PropertySource

will win. This means that you can specify active profiles in application.properties

then replace them using the command line switch.

Sometimes it is useful to have profile-specific properties that add to the active profiles rather than replace them. The spring.profiles.include

property can be used to unconditionally add active profiles.

The

SpringApplication

entry point also has a Java API for setting additional profiles (i.e. on top of those activated by the spring.profiles.active

property): see the setAdditionalProfiles() method.

For example, when an application with following properties is run using the switch

-spring.profiles.active=prod

the proddb

and prodmq

profiles will also be activated:

---

my.property

: fromyamlfile

---

spring.profiles

: prod

spring.profiles.include

: proddb,prodmq

Note

Remember that the spring.profiles

property can be defined in a YAML document to determine when this particular document is included in the configuration. See

Section 69.6,

“Change configuration depending on the environment”

for more details.

25.2 Programmatically setting profiles

You can programmatically set active profiles by calling

SpringApplication.setAdditionalProfiles(…)

before your application runs. It is also possible to activate profiles using Spring’s

ConfigurableEnvironment

interface.

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25.3 Profile-specific configuration files

Profile-specific variants of both application.properties

(or application.yml

) and files referenced via

@ConfigurationProperties

are considered as files are loaded. See

Section 24.4,

“Profile-specific properties”

for details.

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26. Logging

Spring Boot uses Commons Logging for all internal logging, but leaves the underlying log implementation open. Default configurations are provided for Java Util Logging , Log4J , Log4J2 and Logback . In each case loggers are pre-configured to use console output with optional file output also available.

By default, If you use the ‘Starter POMs’, Logback will be used for logging. Appropriate Logback routing is also included to ensure that dependent libraries that use Java Util Logging, Commons Logging, Log4J or SLF4J will all work correctly.

Tip

There are a lot of logging frameworks available for Java. Don’t worry if the above list seems confusing. Generally you won’t need to change your logging dependencies and the Spring Boot defaults will work just fine.

26.1 Log format

The default log output from Spring Boot looks like this:

2014-03-05 10:57:51.112 INFO 45469 --- [ main] org.apache.catalina.core.StandardEngine :

Starting Servlet Engine: Apache Tomcat/7.0.52

2014-03-05 10:57:51.253 INFO 45469 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/] :

Initializing Spring embedded WebApplicationContext

2014-03-05 10:57:51.253 INFO 45469 --- [ost-startStop-1] o.s.web.context.ContextLoader :

Root WebApplicationContext: initialization completed in 1358 ms

2014-03-05 10:57:51.698 INFO 45469 --- [ost-startStop-1] o.s.b.c.e.ServletRegistrationBean :

Mapping servlet: 'dispatcherServlet' to [/]

2014-03-05 10:57:51.702 INFO 45469 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean :

Mapping filter: 'hiddenHttpMethodFilter' to: [/*]

The following items are output:

• Date and Time — Millisecond precision and easily sortable.

• Log Level —

ERROR

,

WARN

,

INFO

,

DEBUG

or

TRACE

.

• Process ID.

• A

---

separator to distinguish the start of actual log messages.

• Thread name — Enclosed in square brackets (may be truncated for console output).

• Logger name — This is usually the source class name (often abbreviated).

• The log message.

Note

Logback does not have a

FATAL

level (it is mapped to

ERROR

)

26.2 Console output

The default log configuration will echo messages to the console as they are written. By default

ERROR

,

WARN

and

INFO

level messages are logged. You can also enable a “debug” mode by starting your application with a

--debug

flag.

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$ java -jar myapp.jar --debug

Note

you can also specify debug=true

in your application.properties

.

When the debug mode is enabled, a selection of core loggers (embedded container, Hibernate and

Spring) are configured to output more information. Enabling the debug mode does not configure your application log all messages with

DEBUG

level.

Color-coded output

If your terminal supports ANSI, color output will be used to aid readability. You can set spring.output.ansi.enabled

to a supported value to override the auto detection.

Color coding is configured using the

%clr

conversion word. In its simplest form the converter will color the output according to the log level, for example:

%clr(%5p)

The mapping of log level to a color is as follows:

Level

FATAL

ERROR

WARN

INFO

DEBUG

TRACE

Color

Red

Red

Yellow

Green

Green

Green

Alternatively, you can specify the color or style that should be used by providing it as an option to the conversion. For example, to make the text yellow:

%clr(%d{yyyy-MM-dd HH:mm:ss.SSS}){yellow}

The following colors and styles are supported:

• blue

• cyan

• faint

• green

• magenta

• red

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• yellow

26.3 File output

By default, Spring Boot will only log to the console and will not write log files. If you want to write log files in addition to the console output you need to set a logging.file

or logging.path

property

(for example in your application.properties

).

The following table shows how the logging.*

properties can be used together:

Table 26.1. Logging properties

(none)

Specific file

(none)

(none)

(none)

Specific directory

Description

my.log

Console only logging.

Writes to the specified log file. Names can be an exact location or relative to the current directory.

/var/log

Writes spring.log

to the specified directory. Names can be an exact location or relative to the current directory.

Log files will rotate when they reach 10 Mb and as with console output,

ERROR

,

WARN

and

INFO

level messages are logged by default.

Note

The logging system is initialized early in the application lifecycle and as such logging properties will not be found in property files loaded via

@PropertySource

annotations.

Tip

Logging properties are independent of the actual logging infrastructure. As a result, specific configuration keys (such as logback.configurationFile

for Logback) are not managed by spring Boot.

26.4 Log Levels

All the supported logging systems can have the logger levels set in the Spring

Environment

(so for example in application.properties

) using ‘logging.level.*=LEVEL’ where ‘LEVEL’ is one of

TRACE, DEBUG, INFO, WARN, ERROR, FATAL, OFF. The root

logger can be configured using logging.level.root

. Example application.properties

:

logging.level.root

=WARN

logging.level.org.springframework.web

=DEBUG

logging.level.org.hibernate

=ERROR

Note

By default Spring Boot remaps Thymeleaf

INFO

messages so that they are logged at

DEBUG level. This helps to reduce noise in the standard log output. See

LevelRemappingAppender for details of how you can apply remapping in your own configuration.

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26.5 Custom log configuration

The various logging systems can be activated by including the appropriate libraries on the classpath, and further customized by providing a suitable configuration file in the root of the classpath, or in a location specified by the Spring

Environment

property logging.config

.

Note

Since logging is initialized before the

ApplicationContext

is created, it isn’t possible to control logging from

@PropertySources

in Spring

@Configuration

files. System properties and the conventional Spring Boot external configuration files work just fine.)

Depending on your logging system, the following files will be loaded:

Logging System

Logback

Log4j

Log4j2

JDK (Java Util Logging)

Customization

logback-spring.xml

, logbackspring.groovy

, logback.xml

or logback.groovy

log4j-spring.properties

, log4jspring.xml

, log4j.properties

or log4j.xml

log4j2-spring.xml

or log4j2.xml

logging.properties

Note

When possible we recommend that you use the

-spring

variants for your logging configuration

(for example logback-spring.xml

rather than logback.xml

). If you use standard configuration locations, Spring cannot completely control log initialization.

Warning

There are known classloading issues with Java Util Logging that cause problems when running from an ‘executable jar’. We recommend that you avoid it if at all possible.

To help with the customization some other properties are transferred from the Spring

Environment to System properties:

Spring Environment

logging.exceptionconversion-word logging.file

logging.path

System Property

LOG_FILE

LOG_PATH

Comments

used when logging exceptions.

Used in default log configuration if defined.

Used in default log configuration if defined.

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Spring Environment

logging.pattern.console

logging.pattern.file

logging.pattern.level

PID

System Property

CONSOLE_LOG_PATTERN

FILE_LOG_PATTERN

LOG_LEVEL_PATTERN

PID

Comments

The log pattern to use on the console (stdout). (Not supported with JDK logger.)

The log pattern to use in a file

(if LOG_FILE enabled). (Not supported with JDK logger.)

The format to use to render the log level (default

%5p

). (The logging.pattern.level

form is only supported by

Logback.)

The current process ID

(discovered if possible and when not already defined as an

OS environment variable).

All the logging systems supported can consult System properties when parsing their configuration files.

See the default configurations in spring-boot.jar

for examples.

Tip

If you want to use a placeholder in a logging property, you should use

Spring Boot’s syntax

and not the syntax of the underlying framework. Notably, if you’re using Logback, you should use

: as the delimiter between a property name and its default value and not

:-

.

Tip

You can add MDC and other ad-hoc content to log lines by overriding only the

LOG_LEVEL_PATTERN

(or logging.pattern.level

with Logback). For example, if you use logging.pattern.level=user:%X{user} %5p

then the default log format will contain an

MDC entry for "user" if it exists, e.g.

2015-09-30 12:30:04.031 user:juergen INFO 22174 --- [ nio-8080-exec-0] demo.Controller Handling

authenticated request

26.6 Logback extensions

Spring Boot includes a number of extensions to Logback which can help with advanced configuration.

You can use these extensions in your logback-spring.xml

configuration file.

Note

You cannot use extensions in the standard logback.xml

configuration file since it’s loaded too early. You need to either use logback-spring.xml

or define a logging.config

property.

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Profile-specific configuration

The

<springProfile>

tag allows you to optionally include or exclude sections of configuration based on the active Spring profiles. Profile sections are supported anywhere within the

<configuration> element. Use the name

attribute to specify which profile accepts the configuration. Multiple profiles can be specified using a comma-separated list.

<springProfile name

=

"staging" >

<!-- configuration to be enabled when the "staging" profile is active -->

</springProfile>

<springProfile name

=

"dev, staging" >

<!-- configuration to be enabled when the "dev" or "staging" profiles are active -->

</springProfile>

<springProfile name

=

"!production" >

<!-- configuration to be enabled when the "production" profile is not active -->

</springProfile>

Environment properties

The

<springProperty>

tag allows you to surface properties from the Spring

Environment

for use within Logback. This can be useful if you want to access values from your application.properties

file in your logback configuration. The tag works in a similar way to Logback’s standard

<property> tag, but rather than specifying a direct value

you specify the source

of the property (from the

Environment

). You can use the scope

attribute if you need to store the property somewhere other than in local

scope.

<springProperty scope

=

"context" name

=

"fluentHost" source

=

"myapp.fluentd.host" />

<appender name

=

"FLUENT" class

=

"ch.qos.logback.more.appenders.DataFluentAppender" >

<remoteHost>

${fluentHost}

</remoteHost>

...

</appender>

Tip

The

RelaxedPropertyResolver

is used to access

Environment

properties. If specify the source

in dashed notation ( my-property-name

) all the relaxed variations will be tried

( myPropertyName

,

MY_PROPERTY_NAME

etc).

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27. Developing web applications

Spring Boot is well suited for web application development. You can easily create a self-contained HTTP server using embedded Tomcat, Jetty, or Undertow. Most web applications will use the spring-bootstarter-web

module to get up and running quickly.

If you haven’t yet developed a Spring Boot web application you can follow the "Hello World!" example in the

Getting started

section.

27.1 The ‘Spring Web MVC framework’

The Spring Web MVC framework (often referred to as simply ‘Spring MVC’) is a rich ‘model view controller’ web framework. Spring MVC lets you create special

@Controller

or

@RestController beans to handle incoming HTTP requests. Methods in your controller are mapped to HTTP using

@RequestMapping

annotations.

Here is a typical example

@RestController

to serve JSON data:

@RestController

@RequestMapping(value="/users")

public class

MyRestController {

@RequestMapping(value="/{user}", method=RequestMethod.GET)

public

User getUser( @PathVariable Long user) {

// ...

}

@RequestMapping(value="/{user}/customers", method=RequestMethod.GET)

List<Customer> getUserCustomers( @PathVariable Long user) {

// ...

}

@RequestMapping(value="/{user}", method=RequestMethod.DELETE)

public

User deleteUser( @PathVariable Long user) {

// ...

}

}

Spring MVC is part of the core Spring Framework and detailed information is available in the reference documentation . There are also several guides available at spring.io/guides that cover Spring MVC.

Spring MVC auto-configuration

Spring Boot provides auto-configuration for Spring MVC that works well with most applications.

The auto-configuration adds the following features on top of Spring’s defaults:

• Inclusion of

ContentNegotiatingViewResolver

and

BeanNameViewResolver

beans.

• Support for serving static resources, including support for WebJars (see below).

• Automatic registration of

Converter

,

GenericConverter

,

Formatter

beans.

• Support for

HttpMessageConverters

(see below).

• Automatic registration of

MessageCodesResolver

(see below).

• Static index.html

support.

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• Custom

Favicon

support.

• Automatic use of a

ConfigurableWebBindingInitializer

bean (see below).

If you want to take complete control of Spring MVC, you can add your own

@Configuration

annotated with

@EnableWebMvc

. If you want to keep Spring Boot MVC features, and you just want to add additional

MVC configuration (interceptors, formatters, view controllers etc.) you can add your own

@Bean

of type

WebMvcConfigurerAdapter

, but without

@EnableWebMvc

.

HttpMessageConverters

Spring MVC uses the

HttpMessageConverter

interface to convert HTTP requests and responses.

Sensible defaults are included out of the box, for example Objects can be automatically converted to

JSON (using the Jackson library) or XML (using the Jackson XML extension if available, else using

JAXB). Strings are encoded using

UTF-8

by default.

If you need to add or customize converters you can use Spring Boot’s

HttpMessageConverters class:

import

org.springframework.boot.autoconfigure.web.HttpMessageConverters;

import

org.springframework.context.annotation.*;

import

org.springframework.http.converter.*;

@Configuration

public class

MyConfiguration {

@Bean

public

HttpMessageConverters customConverters() {

HttpMessageConverter<?> additional = ...

HttpMessageConverter<?> another = ...

return new

HttpMessageConverters(additional, another);

}

}

Any

HttpMessageConverter

bean that is present in the context will be added to the list of converters.

You can also override default converters that way.

MessageCodesResolver

Spring MVC has a strategy for generating error codes for rendering error messages from binding errors:

MessageCodesResolver

. Spring Boot will create one for you if you set the spring.mvc.messagecodes-resolver.format

property

PREFIX_ERROR_CODE

or

POSTFIX_ERROR_CODE

(see the enumeration in

DefaultMessageCodesResolver.Format

).

Static Content

By default Spring Boot will serve static content from a directory called

/static

(or

/public

or

/ resources

or

/META-INF/resources

) in the classpath or from the root of the

ServletContext

.

It uses the

ResourceHttpRequestHandler

from Spring MVC so you can modify that behavior by adding your own

WebMvcConfigurerAdapter

and overriding the addResourceHandlers

method.

In a stand-alone web application the default servlet from the container is also enabled, and acts as a fallback, serving content from the root of the

ServletContext

if Spring decides not to handle it. Most of the time this will not happen (unless you modify the default MVC configuration) because Spring will always be able to handle requests through the

DispatcherServlet

.

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You can customize the static resource locations using spring.resources.staticLocations

(replacing the default values with a list of directory locations). If you do this the default welcome page detection will switch to your custom locations, so if there is an index.html

in any of your locations on startup, it will be the home page of the application.

In addition to the ‘standard’ static resource locations above, a special case is made for Webjars content .

Any resources with a path in

/webjars/**

will be served from jar files if they are packaged in the

Webjars format.

Tip

Do not use the src/main/webapp

directory if your application will be packaged as a jar. Although this directory is a common standard, it will only work with war packaging and it will be silently ignored by most build tools if you generate a jar.

Spring Boot also supports advanced resource handling features provided by Spring MVC, allowing use cases such as cache busting static resources or using version agnostic URLs for Webjars.

For example, the following configuration will configure a cache busting solution for all static resources, effectively adding a content hash in URLs, such as

<link href="/css/ spring-2a2d595e6ed9a0b24f027f2b63b134d6.css"/>

:

spring.resources.chain.strategy.content.enabled

=true

spring.resources.chain.strategy.content.paths

=/**

Note

Links to resources are rewritten at runtime in template, thanks to a

ResourceUrlEncodingFilter

, auto-configured for Thymeleaf and Velocity. You should manually declare this filter when using JSPs. Other template engines aren’t automatically supported right now, but can be with custom template macros/helpers and the use of the

ResourceUrlProvider

.

When loading resources dynamically with, for example, a JavaScript module loader, renaming files is not an option. That’s why other strategies are also supported and can be combined. A "fixed" strategy will add a static version string in the URL, without changing the file name:

spring.resources.chain.strategy.content.enabled

=true

spring.resources.chain.strategy.content.paths

=/**

spring.resources.chain.strategy.fixed.enabled

=true

spring.resources.chain.strategy.fixed.paths

=/js/lib/

spring.resources.chain.strategy.fixed.version

=v12

With this configuration, JavaScript modules located under

"/js/lib/"

will use a fixed versioning strategy

"/v12/js/lib/mymodule.js"

while other resources will still use the content one

<link href="/css/spring-2a2d595e6ed9a0b24f027f2b63b134d6.css"/>

.

See

ResourceProperties

for more of the supported options.

Tip

This feature has been thoroughly described in a dedicated blog post and in Spring Framework’s reference documentation .

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ConfigurableWebBindingInitializer

Spring MVC uses a

WebBindingInitializer

to initialize a

WebDataBinder

for a particular request. If you create your own

ConfigurableWebBindingInitializer @Bean

, Spring Boot will automatically configure Spring MVC to use it.

Template engines

As well as REST web services, you can also use Spring MVC to serve dynamic HTML content. Spring

MVC supports a variety of templating technologies including Velocity, FreeMarker and JSPs. Many other templating engines also ship their own Spring MVC integrations.

Spring Boot includes auto-configuration support for the following templating engines:

• FreeMarker

• Groovy

• Thymeleaf

• Velocity

• Mustache

Tip

JSPs should be avoided if possible, there are several

known limitations when using them with

embedded servlet containers.

When you’re using one of these templating engines with the default configuration, your templates will be picked up automatically from src/main/resources/templates

.

Tip

IntelliJ IDEA orders the classpath differently depending on how you run your application. Running your application in the IDE via its main method will result in a different ordering to when you run your application using Maven or Gradle or from its packaged jar. This can cause Spring

Boot to fail to find the templates on the classpath. If you’re affected by this problem you can reorder the classpath in the IDE to place the module’s classes and resources first. Alternatively, you can configure the template prefix to search every templates directory on the classpath: classpath*:/templates/

.

Error Handling

Spring Boot provides an

/error

mapping by default that handles all errors in a sensible way, and it is registered as a ‘global’ error page in the servlet container. For machine clients it will produce a

JSON response with details of the error, the HTTP status and the exception message. For browser clients there is a ‘whitelabel’ error view that renders the same data in HTML format (to customize it just add a

View

that resolves to ‘error’). To replace the default behaviour completely you can implement

ErrorController

and register a bean definition of that type, or simply add a bean of type

ErrorAttributes

to use the existing mechanism but replace the contents.

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Tip

The

BasicErrorController

can be used as a base class for a custom

ErrorController

.

This is particularly useful if you want to add a handler for a new content type (the default is to handle text/html

specifically and provide a fallback for everything else). To do that just extend

BasicErrorController

and add a public method with a

@RequestMapping

that has a produces

attribute, and create a bean of your new type.

You can also define a

@ControllerAdvice

to customize the JSON document to return for a particular controller and/or exception type.

@ControllerAdvice(basePackageClasses = FooController.class)

public class

FooControllerAdvice

extends

ResponseEntityExceptionHandler {

@ExceptionHandler(YourException.class)

@ResponseBody

ResponseEntity<?> handleControllerException(HttpServletRequest request, Throwable ex) {

HttpStatus status = getStatus(request);

return new

ResponseEntity<>(

new

CustomErrorType(status.value(), ex.getMessage()), status);

}

private

HttpStatus getStatus(HttpServletRequest request) {

Integer statusCode = (Integer) request.getAttribute(

"javax.servlet.error.status_code"

);

if

(statusCode == null) {

return

HttpStatus.INTERNAL_SERVER_ERROR;

}

return

HttpStatus.valueOf(statusCode);

}

}

In the example above, if

YourException

is thrown by a controller defined in the same package as

FooController

, a json representation of the

CustomerErrorType

POJO will be used instead of the

ErrorAttributes

representation.

If you want more specific error pages for some conditions, the embedded servlet containers support a uniform Java DSL for customizing the error handling. Assuming that you have a mapping for

/400

:

@Bean

public

EmbeddedServletContainerCustomizer containerCustomizer(){

return new

MyCustomizer();

}

// ...

private static class

MyCustomizer

implements

EmbeddedServletContainerCustomizer {

@Override

public void

customize(ConfigurableEmbeddedServletContainer container) {

container.addErrorPages(

new

ErrorPage(HttpStatus.BAD_REQUEST,

"/400"

));

}

}

You can also use regular Spring MVC features like

@ExceptionHandler

methods and

@ControllerAdvice

. The

ErrorController

will then pick up any unhandled exceptions.

N.B. if you register an

ErrorPage

with a path that will end up being handled by a

Filter

(e.g. as is common with some non-Spring web frameworks, like Jersey and Wicket), then the

Filter

has to be explicitly registered as an

ERROR

dispatcher, e.g.

@Bean

public

FilterRegistrationBean myFilter() {

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FilterRegistrationBean registration =

new

FilterRegistrationBean();

registration.setFilter(

new

MyFilter());

...

registration.setDispatcherTypes(EnumSet.allOf(DispatcherType.

class

));

return

registration;

}

(the default

FilterRegistrationBean

does not include the

ERROR

dispatcher type).

Error Handling on WebSphere Application Server

When deployed to a servlet container, a Spring Boot uses its error page filter to forward a request with an error status to the appropriate error page. The request can only be forwarded to the correct error page if the response has not already been committed. By default, WebSphere Application Server 8.0 and later commits the response upon successful completion of a servlet’s service method. You should disable this behaviour by setting com.ibm.ws.webcontainer.invokeFlushAfterService

to false

Spring HATEOAS

If you’re developing a RESTful API that makes use of hypermedia, Spring Boot provides autoconfiguration for Spring HATEOAS that works well with most applications. The auto-configuration replaces the need to use

@EnableHypermediaSupport

and registers a number of beans to ease building hypermedia-based applications including a

LinkDiscoverers

(for client side support) and an

ObjectMapper

configured to correctly marshal responses into the desired representation.

The

ObjectMapper

will be customized based on the spring.jackson.*

properties or a

Jackson2ObjectMapperBuilder

bean if one exists.

You can take control of Spring HATEOAS’s configuration by using

@EnableHypermediaSupport

.

Note that this will disable the

ObjectMapper

customization described above.

CORS support

Cross-origin resource sharing (CORS) is a W3C specification implemented by most browsers that allows you to specify in a flexible way what kind of cross domain requests are authorized, instead of using some less secure and less powerful approaches like IFRAME or JSONP.

As of version 4.2, Spring MVC supports CORS out of the box. Using controller method CORS configuration with

@CrossOrigin

annotations in your Spring Boot application does not require any specific configuration. Global CORS configuration can be defined by registering a

WebMvcConfigurer bean with a customized addCorsMappings(CorsRegistry)

method:

@Configuration

public class

MyConfiguration {

@Bean

public

WebMvcConfigurer corsConfigurer() {

return new

WebMvcConfigurerAdapter() {

@Override

public void

addCorsMappings(CorsRegistry registry) {

registry.addMapping(

"/api/**"

);

}

};

}

}

27.2 JAX-RS and Jersey

If you prefer the JAX-RS programming model for REST endpoints you can use one of the available implementations instead of Spring MVC. Jersey 1.x and Apache CXF work quite well out of the box

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Servlet

or

Filter

as a

@Bean

in your application context. Jersey 2.x has some native Spring support so we also provide auto-configuration support for it in Spring Boot together with a starter.

To get started with Jersey 2.x just include the spring-boot-starter-jersey

as a dependency and then you need one

@Bean

of type

ResourceConfig

in which you register all the endpoints:

@Component

public class

JerseyConfig

extends

ResourceConfig {

public

JerseyConfig() {

register(Endpoint.

class

);

}

}

All the registered endpoints should be

@Components

with HTTP resource annotations (

@GET

etc.), e.g.

@Component

@Path("/hello")

public class

Endpoint {

@GET

public

String message() {

return

"Hello"

;

}

}

Since the

Endpoint

is a Spring

@Component

its lifecycle is managed by Spring and you can

@Autowired

dependencies and inject external configuration with

@Value

. The Jersey servlet will be registered and mapped to

/*

by default. You can change the mapping by adding

@ApplicationPath to your

ResourceConfig

.

By default Jersey will be set up as a Servlet in a

@Bean

of type

ServletRegistrationBean named jerseyServletRegistration

. You can disable or override that bean by creating one of your own with the same name. You can also use a Filter instead of a Servlet by setting spring.jersey.type=filter

(in which case the

@Bean

to replace or override is jerseyFilterRegistration

). The servlet has an

@Order

which you can set with spring.jersey.filter.order

. Both the Servlet and the Filter registrations can be given init parameters using spring.jersey.init.*

to specify a map of properties.

There is a Jersey sample so you can see how to set things up. There is also a Jersey 1.x sample .

Note that in the Jersey 1.x sample that the spring-boot maven plugin has been configured to unpack some Jersey jars so they can be scanned by the JAX-RS implementation (because the sample asks for them to be scanned in its

Filter

registration). You may need to do the same if any of your JAX-

RS resources are packaged as nested jars.

27.3 Embedded servlet container support

Spring Boot includes support for embedded Tomcat, Jetty, and Undertow servers. Most developers will simply use the appropriate ‘Starter POM’ to obtain a fully configured instance. By default the embedded server will listen for HTTP requests on port

8080

.

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Servlets, Filters, and listeners

When using an embedded servlet container you can register Servlets, Filters and all the listeners from the Servlet spec (e.g.

HttpSessionListener

) either by using Spring beans or by scanning for Servlet components.

Registering Servlets, Filters, and listeners as Spring beans

Any

Servlet

,

Filter

or Servlet

*Listener

instance that is a Spring bean will be registered with the embedded container. This can be particularly convenient if you want to refer to a value from your application.properties

during configuration.

By default, if the context contains only a single Servlet it will be mapped to

/

. In the case of multiple

Servlet beans the bean name will be used as a path prefix. Filters will map to

/*

.

If convention-based mapping is not flexible enough you can use the

ServletRegistrationBean

,

FilterRegistrationBean

and

ServletListenerRegistrationBean

classes for complete control.

Servlet Context Initialization

Embedded

3.0+ servlet containers will not directly javax.servlet.ServletContainerInitializer

org.springframework.web.WebApplicationInitializer

interface. This is an intentional design decision intended to reduce the risk that 3rd party libraries designed to run inside a war will break

Spring Boot applications.

execute interface, the or

Servlet

Spring’s

If you need to perform servlet context initialization in a Spring

Boot application, you should register a bean that implements the org.springframework.boot.context.embedded.ServletContextInitializer

interface.

The single onStartup

method provides access to the

ServletContext

, and can easily be used as an adapter to an existing `WebApplicationInitializer if necessary.

Scanning for Servlets, Filters, and listeners

When using an embedded container, automatic registration of

@WebServlet

,

@WebFilter

, and

@WebListener

annotated classes can be enabled using

@ServletComponentScan

.

Tip

@ServletComponentScan

will have no effect in a standalone container, where the container’s built-in discovery mechanisms will be used instead.

The EmbeddedWebApplicationContext

Under the hood Spring Boot uses a new type of

ApplicationContext

for embedded servlet container support. The

EmbeddedWebApplicationContext

is a special type of

WebApplicationContext that bootstraps itself by searching for a single

EmbeddedServletContainerFactory

bean. Usually a

TomcatEmbeddedServletContainerFactory

,

JettyEmbeddedServletContainerFactory

, or

UndertowEmbeddedServletContainerFactory

will have been auto-configured.

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Note

You usually won’t need to be aware of these implementation classes. Most applications will be auto-configured and the appropriate

ApplicationContext

and

EmbeddedServletContainerFactory

will be created on your behalf.

Customizing embedded servlet containers

Common servlet container settings can be configured using Spring

Environment

properties. Usually you would define the properties in your application.properties

file.

Common server settings include:

• server.port

— The listen port for incoming HTTP requests.

• server.address

— The interface address to bind to.

• server.session.timeout

— A session timeout.

See the

ServerProperties

class for a complete list.

Programmatic customization

If you need to configure your embedded servlet container programmatically you can register a Spring bean that implements the

EmbeddedServletContainerCustomizer interface.

EmbeddedServletContainerCustomizer provides access to the

ConfigurableEmbeddedServletContainer

which includes numerous customization setter methods.

import

org.springframework.boot.context.embedded.*;

import

org.springframework.stereotype.Component;

@Component

public class

CustomizationBean

implements

EmbeddedServletContainerCustomizer {

@Override

public void

customize(ConfigurableEmbeddedServletContainer container) {

container.setPort(9000);

}

}

Customizing ConfigurableEmbeddedServletContainer directly

If the above customization techniques are too limited, you can register the

TomcatEmbeddedServletContainerFactory

,

JettyEmbeddedServletContainerFactory or

UndertowEmbeddedServletContainerFactory

bean yourself.

@Bean

public

EmbeddedServletContainerFactory servletContainer() {

TomcatEmbeddedServletContainerFactory factory =

new

TomcatEmbeddedServletContainerFactory();

factory.setPort(9000);

factory.setSessionTimeout(10, TimeUnit.MINUTES);

factory.addErrorPages(

new

ErrorPage(HttpStatus.NOT_FOUND,

"/notfound.html"

));

return

factory;

}

Setters are provided for many configuration options. Several protected method ‘hooks’ are also provided should you need to do something more exotic. See the source code documentation for details.

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JSP limitations

When running a Spring Boot application that uses an embedded servlet container (and is packaged as an executable archive), there are some limitations in the JSP support.

• With Tomcat it should work if you use war packaging, i.e. an executable war will work, and will also be deployable to a standard container (not limited to, but including Tomcat). An executable jar will not work because of a hard coded file pattern in Tomcat.

• Jetty does not currently work as an embedded container with JSPs.

• Undertow does not support JSPs.

There is a JSP sample so you can see how to set things up.

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28. Security

If Spring Security is on the classpath then web applications will be secure by default with ‘basic’ authentication on all HTTP endpoints. To add method-level security to a web application you can also add

@EnableGlobalMethodSecurity

with your desired settings. Additional information can be found in the Spring Security Reference .

The default

AuthenticationManager

has a single user (‘user’ username and random password, printed at INFO level when the application starts up)

Using default security password: 78fa095d-3f4c-48b1-ad50-e24c31d5cf35

Note

If you fine tune your logging configuration, ensure that the org.springframework.boot.autoconfigure.security

category is set to log

INFO messages, otherwise the default password will not be printed.

You can change the password by providing a security.user.password

. This and other useful properties are externalized via

SecurityProperties

(properties prefix "security").

The default security configuration is implemented in

SecurityAutoConfiguration

and in the classes imported from there (

SpringBootWebSecurityConfiguration

for web security and

AuthenticationManagerConfiguration

for authentication configuration which is also relevant in non-web applications). To switch off the default web security configuration completely you can add a bean with

@EnableWebSecurity

(this does not disable the authentication manager configuration). To customize it you normally use external properties and beans of type

WebSecurityConfigurerAdapter

(e.g. to add form-based login). To also switch off the authentication manager configuration you can add a bean of type

AuthenticationManager

, or else configure the global

AuthenticationManager

by autowiring an

AuthenticationManagerBuilder

into a method in one of your

@Configuration

classes. There are several secure applications in the Spring Boot samples to get you started with common use cases.

The basic features you get out of the box in a web application are:

• An

AuthenticationManager

bean with in-memory store and a single user (see

SecurityProperties.User

for the properties of the user).

• Ignored (insecure) paths for common static resource locations (

/css/**

,

/js/**

,

/images/**

and

**/favicon.ico

).

• HTTP Basic security for all other endpoints.

• Security events published to Spring’s

ApplicationEventPublisher

(successful and unsuccessful authentication and access denied).

• Common low-level features (HSTS, XSS, CSRF, caching) provided by Spring Security are on by default.

All of the above can be switched on and off or modified using external properties ( security.*

). To override the access rules without changing any other auto-configured features add a

@Bean

of type

WebSecurityConfigurerAdapter

with

@Order(SecurityProperties.ACCESS_OVERRIDE_ORDER)

.

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28.1 OAuth2

If you have spring-security-oauth2

on your classpath you can take advantage of some autoconfiguration to make it easy to set up Authorization or Resource Server.

Authorization Server

To create an Authorization Server and grant access tokens you need to use

@EnableAuthorizationServer

and provide security.oauth2.client.client-id

and security.oauth2.client.client-secret]

properties. The client will be registered for you in an in-memory repository.

Having done that you will be able to use the client credentials to create an access token, for example:

$ curl client:[email protected]:8080/oauth/token -d grant_type=password -d username=user -d password=pwd

The basic auth credentials for the

/token

endpoint are the client-id

and client-secret

. The user credentials are the normal Spring Security user details (which default in Spring Boot to “user” and a random password).

To switch off the auto-configuration and configure the Authorization Server features yourself just add a

@Bean

of type

AuthorizationServerConfigurer

.

Resource Server

To use the access token you need a Resource Server (which can be the same as the Authorization

Server). Creating a Resource Server is easy, just add

@EnableResourceServer

and provide some configuration to allow the server to decode access tokens. If your application is also an Authorization

Server it already knows how to decode tokens, so there is nothing else to do. If your app is a standalone service then you need to give it some more configuration, one of the following options:

• security.oauth2.resource.user-info-uri to use the

/me resource (e.g.

uaa.run.pivotal.io/userinfo

on PWS)

• security.oauth2.resource.token-info-uri

to use the token decoding endpoint (e.g.

uaa.run.pivotal.io/check_token

on PWS).

If you specify both the user-info-uri

and the token-info-uri

then you can set a flag to say that one is preferred over the other ( prefer-token-info=true

is the default).

Alternatively (instead of user-info-uri

or token-info-uri

) if the tokens are JWTs you can configure a security.oauth2.resource.jwt.key-value

to decode them locally (where the key is a verification key). The verification key value is either a symmetric secret or PEM-encoded RSA public key. If you don’t have the key and it’s public you can provide a URI where it can be downloaded (as a

JSON object with a “value” field) with security.oauth2.resource.jwt.key-uri

. E.g. on PWS:

$ curl https://uaa.run.pivotal.io/token_key

{"alg":"SHA256withRSA","value":"-----BEGIN PUBLIC KEY-----\nMIIBI...\n-----END PUBLIC KEY-----\n"}

Warning

If you use the security.oauth2.resource.jwt.key-uri

the authorization server needs to be running when your application starts up. It will log a warning if it can’t find the key, and tell you what to do to fix it.

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28.2 Token Type in User Info

Google, and certain other 3rd party identity providers, are more strict about the token type name that is sent in the headers to the user info endpoint. The default is “Bearer” which suits most providers and matches the spec, but if you need to change it you can set security.oauth2.resource.tokentype

.

28.3 Customizing the User Info RestTemplate

If you have a user-info-uri

, the resource server features use an

OAuth2RestTemplate internally to fetch user details for authentication. This is provided as a qualified

@Bean

with id userInfoRestTemplate

, but you shouldn’t need to know that to just use it. The default should be fine for most providers, but occasionally you might need to add additional interceptors, or change the request authenticator (which is how the token gets attached to outgoing requests). To add a customization just create a bean of type

UserInfoRestTemplateCustomizer

- it has a single method that will be called after the bean is created but before it is initialized. The rest template that is being customized here is

only used internally to carry out authentication.

Tip

To set an RSA key value in YAML use the “pipe” continuation marker to split it over multiple lines

(“|”) and remember to indent the key value (it’s a standard YAML language feature). Example:

security

:

oauth2

:

resource

:

jwt

:

keyValue

: |

-----BEGIN PUBLIC KEY-----

MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKC...

-----END PUBLIC KEY-----

Client

To make your webapp into an OAuth2 client you can simply add

@EnableOAuth2Client and Spring Boot will create an

OAuth2RestTemplate

for you to

@Autowire

. It uses the security.oauth2.client.*

as credentials (the same as you might be using in the Authorization

Server), but in addition it will need to know the authorization and token URIs in the Authorization Server.

For example:

application.yml. security

:

oauth2

:

client

:

clientId

: bd1c0a783ccdd1c9b9e4

clientSecret

: 1a9030fbca47a5b2c28e92f19050bb77824b5ad1

accessTokenUri

: https://github.com/login/oauth/access_token

userAuthorizationUri

: https://github.com/login/oauth/authorize

clientAuthenticationScheme

: form

An application with this configuration will redirect to Github for authorization when you attempt to use the

OAuth2RestTemplate

. If you are already signed into Github you won’t even notice that it has authenticated. These specific credentials will only work if your application is running on port 8080

(register your own client app in Github or other provider for more flexibility).

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To limit the scope that the client asks for when it obtains an access token you can set security.oauth2.client.scope

(comma separated or an array in YAML). By default the scope is empty and it is up to Authorization Server to decide what the defaults should be, usually depending on the settings in the client registration that it holds.

Note

There is also a setting for security.oauth2.client.client-authentication-scheme which defaults to “header” (but you might need to set it to “form” if, like Github for instance, your

OAuth2 provider doesn’t like header authentication). In fact, the security.oauth2.client.* properties are bound to an instance of

AuthorizationCodeResourceDetails

so all its properties can be specified.

Tip

In a non-web application you can still

@Autowire

an

OAuth2RestOperations

and it is still wired into the security.oauth2.client.*

configuration. In this case it is a “client credentials token grant” you will be asking for if you use it (and there is no need to use

@EnableOAuth2Client

or

@EnableOAuth2Sso

). To switch it off, just remove the security.oauth2.client.client-id

from your configuration (or make it the empty string).

Single Sign On

An OAuth2 Client can be used to fetch user details from the provider (if such features are available) and then convert them into an

Authentication

token for Spring Security. The Resource Server above support this via the user-info-uri

property This is the basis for a Single Sign On (SSO) protocol based on OAuth2, and Spring Boot makes it easy to participate by providing an annotation

@EnableOAuth2Sso

. The Github client above can protect all its resources and authenticate using the

Github

/user/

endpoint, by adding that annotation and declaring where to find the endpoint (in addition to the security.oauth2.client.*

configuration already listed above):

application.yml. security

:

oauth2

:

...

resource

:

userInfoUri

: https://api.github.com/user

preferTokenInfo

:

false

Since all paths are secure by default, there is no “home” page that you can show to unauthenticated users and invite them to login (by visiting the

/login

path, or the path specified by security.oauth2.sso.login-path

).

To customize the access rules or paths to protect, so you can add a “home” page for instance,

@EnableOAuth2Sso

can be added to a

WebSecurityConfigurerAdapter

and the annotation will cause it to be decorated and enhanced with the necessary pieces to get the

/login

path working. For example, here we simply allow unauthenticated access to the home page at "/" and keep the default for everything else:

@Configuration

public class

WebSecurityConfiguration

extends

WebSecurityConfigurerAdapter {

@Override

public void

init(WebSecurity web) {

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web.ignore(

"/"

);

}

@Override

protected void

configure(HttpSecurity http)

throws

Exception {

http.antMatcher(

"/**"

).authorizeRequests().anyRequest().authenticated();

}

}

28.4 Actuator Security

If the Actuator is also in use, you will find:

• The management endpoints are secure even if the application endpoints are insecure.

• Security events are transformed into

AuditEvents

and published to the

AuditService

.

• The default user will have the

ADMIN

role as well as the

USER

role.

The Actuator security features can be modified using external properties ( management.security.*

).

To override the application access rules add a

@Bean

of type

WebSecurityConfigurerAdapter

and use

@Order(SecurityProperties.ACCESS_OVERRIDE_ORDER)

if you don’t want to override the actuator access rules, or

@Order(ManagementServerProperties.ACCESS_OVERRIDE_ORDER) if you do want to override the actuator access rules.

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29. Working with SQL databases

The Spring Framework provides extensive support for working with SQL databases. From direct JDBC access using

JdbcTemplate

to complete ‘object relational mapping’ technologies such as Hibernate.

Spring Data provides an additional level of functionality, creating

Repository

implementations directly from interfaces and using conventions to generate queries from your method names.

29.1 Configure a DataSource

Java’s javax.sql.DataSource

interface provides a standard method of working with database connections. Traditionally a DataSource uses a

URL

along with some credentials to establish a database connection.

Embedded Database Support

It’s often convenient to develop applications using an in-memory embedded database. Obviously, inmemory databases do not provide persistent storage; you will need to populate your database when your application starts and be prepared to throw away data when your application ends.

Tip

The ‘How-to’ section includes a

section on how to initialize a database

Spring Boot can auto-configure embedded H2 , HSQL and Derby databases. You don’t need to provide any connection URLs, simply include a build dependency to the embedded database that you want to use.

For example, typical POM dependencies would be:

<dependency>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter-data-jpa

</artifactId>

</dependency>

<dependency>

<groupId>

org.hsqldb

</groupId>

<artifactId>

hsqldb

</artifactId>

<scope>

runtime

</scope>

</dependency>

Tip

If, for whatever reason, you do configure the connection URL for an embedded database, care should be taken to ensure that the database’s automatic shutdown is disabled. If you’re using

H2 you should use

DB_CLOSE_ON_EXIT=FALSE

to do so. If you’re using HSQLDB, you should ensure that shutdown=true

is not used. Disabling the database’s automatic shutdown allows

Spring Boot to control when the database is closed, thereby ensuring that it happens once access to the database is no longer needed.

Note

You need a dependency on spring-jdbc

for an embedded database to be auto-configured. In this example it’s pulled in transitively via spring-boot-starter-data-jpa

.

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Connection to a production database

Production database connections can also be auto-configured using a pooling

DataSource

. Here’s the algorithm for choosing a specific implementation:

• We prefer the Tomcat pooling

DataSource

for its performance and concurrency, so if that is available we always choose it.

• If HikariCP is available we will use it.

• If Commons DBCP is available we will use it, but we don’t recommend it in production.

• Lastly, if Commons DBCP2 is available we will use it.

If you use the spring-boot-starter-jdbc

or spring-boot-starter-data-jpa

‘starter POMs’ you will automatically get a dependency to tomcat-jdbc

.

Note

You can bypass that algorithm completely and specify the connection pool to use via the spring.datasource.type

property. Also, additional connection pools can always be configured manually. If you define your own

DataSource

bean, auto-configuration will not occur.

DataSource configuration is controlled by external configuration properties in spring.datasource.*

.

For example, you might declare the following section in application.properties

:

spring.datasource.url

=jdbc:mysql://localhost/test

spring.datasource.username

=dbuser

spring.datasource.password

=dbpass

spring.datasource.driver-class-name

=com.mysql.jdbc.Driver

See

DataSourceProperties

for more of the supported options. Note also that you can configure any of the

DataSource

implementation specific properties via spring.datasource.*

: refer to the documentation of the connection pool implementation you are using for more details.

Tip

You often won’t need to specify the driver-class-name

since Spring boot can deduce it for most databases from the url

.

Note

For a pooling

DataSource

to be created we need to be able to verify that a valid

Driver

class is available, so we check for that before doing anything. I.e. if you set spring.datasource.driverClassName=com.mysql.jdbc.Driver

then that class has to be loadable.

Connection to a JNDI DataSource

If you are deploying your Spring Boot application to an Application Server you might want to configure and manage your DataSource using your Application Servers built-in features and access it using JNDI.

The spring.datasource.jndi-name property can be used as an alternative to the spring.datasource.url

, spring.datasource.username

and

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properties to access the

DataSource

from a specific JNDI location.

For example, the following section in application.properties

shows how you can access a JBoss

AS defined

DataSource

:

spring.datasource.jndi-name

=java:jboss/datasources/customers

29.2 Using JdbcTemplate

Spring’s

JdbcTemplate

and

NamedParameterJdbcTemplate

classes are auto-configured and you can

@Autowire

them directly into your own beans:

import

org.springframework.beans.factory.annotation.Autowired;

import

org.springframework.jdbc.core.JdbcTemplate;

import

org.springframework.stereotype.Component;

@Component

public class

MyBean {

private final

JdbcTemplate jdbcTemplate;

@Autowired

public

MyBean(JdbcTemplate jdbcTemplate) {

this

.jdbcTemplate = jdbcTemplate;

}

// ...

}

29.3 JPA and ‘Spring Data’

The Java Persistence API is a standard technology that allows you to ‘map’ objects to relational databases. The spring-boot-starter-data-jpa

POM provides a quick way to get started. It provides the following key dependencies:

• Hibernate — One of the most popular JPA implementations.

• Spring Data JPA — Makes it easy to implement JPA-based repositories.

• Spring ORMs — Core ORM support from the Spring Framework.

Tip

We won’t go into too many details of JPA or Spring Data here. You can follow the ‘Accessing

Data with JPA’ guide from spring.io

and read the Spring Data JPA and Hibernate reference documentation.

Entity Classes

Traditionally, JPA ‘Entity’ classes are specified in a persistence.xml

file. With Spring Boot this file is not necessary and instead ‘Entity Scanning’ is used. By default all packages below your main configuration class (the one annotated with

@EnableAutoConfiguration

or

@SpringBootApplication

) will be searched.

Any classes annotated with

@Entity

,

@Embeddable

or

@MappedSuperclass

will be considered. A typical entity class would look something like this:

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package

com.example.myapp.domain;

import

java.io.Serializable;

import

javax.persistence.*;

@Entity

public class

City

implements

Serializable {

@Id

@GeneratedValue

private

Long id;

@Column(nullable = false)

private

String name;

@Column(nullable = false)

private

String state;

// ... additional members, often include @OneToMany mappings

protected

City() {

// no-args constructor required by JPA spec

// this one is protected since it shouldn't be used directly

}

public

City(String name, String state) {

this

.name = name;

this

.country = country;

}

public

String getName() {

return this

.name;

}

public

String getState() {

return this

.state;

}

// ... etc

}

Tip

You can customize entity scanning locations using the

@EntityScan

annotation. See the

Section 73.4, “Separate @Entity definitions from Spring configuration”

how-to.

Spring Data JPA Repositories

Spring Data JPA repositories are interfaces that you can define to access data. JPA queries are created automatically from your method names. For example, a

CityRepository

interface might declare a findAllByState(String state)

method to find all cities in a given state.

For more complex queries you can annotate your method using Spring Data’s

Query

annotation.

Spring Data repositories usually extend from the

Repository

or

CrudRepository

interfaces.

If you are using auto-configuration, repositories will be searched from the package containing your main configuration class (the one annotated with

@EnableAutoConfiguration

or

@SpringBootApplication

) down.

Here is a typical Spring Data repository:

package

com.example.myapp.domain;

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import

org.springframework.data.domain.*;

import

org.springframework.data.repository.*;

public interface

CityRepository

extends

Repository<City, Long> {

Page<City> findAll(Pageable pageable);

City findByNameAndCountryAllIgnoringCase(String name, String country);

}

Tip

We have barely scratched the surface of Spring Data JPA. For complete details check their reference documentation .

Creating and dropping JPA databases

By default, JPA databases will be automatically created only if you use an embedded database

(H2, HSQL or Derby). You can explicitly configure JPA settings using spring.jpa.*

properties. For example, to create and drop tables you can add the following to your application.properties

.

spring.jpa.hibernate.ddl-auto=create-drop

Note

Hibernate’s own internal property name for this (if you happen to remember it better) is hibernate.hbm2ddl.auto

. You can set it, along with other Hibernate native properties, using spring.jpa.properties.*

(the prefix is stripped before adding them to the entity manager).

Example: spring.jpa.properties.hibernate.globally_quoted_identifiers=true passes hibernate.globally_quoted_identifiers

to the Hibernate entity manager.

By default the DDL execution (or validation) is deferred until the

ApplicationContext

has started.

There is also a spring.jpa.generate-ddl

flag, but it is not used if Hibernate autoconfig is active because the ddl-auto

settings are more fine-grained.

29.4 Using H2’s web console

The H2 database provides a browser-based console that Spring Boot can auto-configure for you. The console will be auto-configured when the following conditions are met:

• You are developing a web application

• com.h2database:h2

is on the classpath

• You are using

Spring Boot’s developer tools

Tip

If you are not using Spring Boot’s developer tools, but would still like to make use of H2’s console, then you can do so by configuring the spring.h2.console.enabled

property with a value of

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. The H2 console is only intended for use during development so care should be taken to ensure that spring.h2.console.enabled

is not set to true

in production.

Changing the H2 console’s path

By default the console will be available at

/h2-console

. You can customize the console’s path using the spring.h2.console.path

property.

Securing the H2 console

When Spring Security is on the classpath and basic auth is enabled, the H2 console will be automatically secured using basic auth. The following properties can be used to customize the security configuration:

• security.user.role

• security.basic.authorize-mode

• security.basic.enabled

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30. Using jOOQ

Java Object Oriented Querying ( jOOQ ) is a popular product from Data Geekery which generates Java code from your database, and lets you build type safe SQL queries through its fluent API. Both the commercial and open source editions can be used with Spring Boot.

30.1 Code Generation

In order to use jOOQ type-safe queries, you need to generate Java classes from your database schema.

You can follow the instructions in the jOOQ user manual . If you are using the jooq-codegen-maven plugin (and you also use the spring-boot-starter-parent

“parent POM”) you can safely omit the plugin’s

<version>

tag. You can also use Spring Boot defined version variables (e.g. h2.version

) to declare the plugin’s database dependency. Here’s an example:

<plugin>

<groupId>

org.jooq

</groupId>

<artifactId>

jooq-codegen-maven

</artifactId>

<executions>

...

</executions>

<dependencies>

<dependency>

<groupId>

com.h2database

</groupId>

<artifactId>

h2

</artifactId>

<version>

${h2.version}

</version>

</dependency>

</dependencies>

<configuration>

<jdbc>

<driver>

org.h2.Driver

</driver>

<url>

jdbc:h2:~/yourdatabase

</url>

</jdbc>

<generator>

...

</generator>

</configuration>

</plugin>

30.2 Using DSLContext

The fluent API offered by jOOQ is initiated via the org.jooq.DSLContext

interface. Spring Boot will auto-configure a

DSLContext

as a Spring Bean and connect it to your application

DataSource

. To use the

DSLContext

you can just

@Autowire

it:

@Component

public class

JooqExample

implements

CommandLineRunner {

private final

DSLContext create;

@Autowired

public

JooqExample(DSLContext dslContext) {

this

.create = dslContext;

}

}

Tip

The jOOQ manual tends to use a variable named create

to hold the

DSLContext

, we’ve done the same for this example.

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You can then use the

DSLContext

to construct your queries:

public

List<GregorianCalendar> authorsBornAfter1980() {

return this

.create.selectFrom(AUTHOR)

.where(AUTHOR.DATE_OF_BIRTH.greaterThan(

new

GregorianCalendar(1980, 0, 1)))

.fetch(AUTHOR.DATE_OF_BIRTH);

}

30.3 Customizing jOOQ

You can customize the SQL dialect used by jOOQ by setting spring.jooq.sql-dialect

in your application.properties

. For example, to specify Postgres you would add:

spring.jooq.sql-dialect

=Postgres

More advanced customizations can be achieved by defining your own

@Bean

definitions which will be used when the jOOQ

Configuration

is created. You can define beans for the following jOOQ Types:

ConnectionProvider

TransactionProvider

RecordMapperProvider

RecordListenerProvider

ExecuteListenerProvider

VisitListenerProvider

You can also create your own org.jooq.Configuration

@Bean

if you want to take complete control of the jOOQ configuration.

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31. Working with NoSQL technologies

Spring Data provides additional projects that help you access a variety of NoSQL technologies including MongoDB , Neo4J , Elasticsearch , Solr , Redis , Gemfire , Couchbase and Cassandra . Spring

Boot provides auto-configuration for Redis, MongoDB, Elasticsearch, Solr and Cassandra; you can make use of the other projects, but you will need to configure them yourself. Refer to the appropriate reference documentation at projects.spring.io/spring-data .

31.1 Redis

Redis is a cache, message broker and richly-featured key-value store. Spring Boot offers basic autoconfiguration for the Jedis client library and abstractions on top of it provided by Spring Data Redis . There is a spring-boot-starter-redis

‘Starter POM’ for collecting the dependencies in a convenient way.

Connecting to Redis

You can inject an auto-configured

RedisConnectionFactory

,

StringRedisTemplate

or vanilla

RedisTemplate

instance as you would any other Spring Bean. By default the instance will attempt to connect to a Redis server using localhost:6379

:

@Component

public class

MyBean {

private

StringRedisTemplate template;

@Autowired

public

MyBean(StringRedisTemplate template) {

this

.template = template;

}

// ...

}

If you add a

@Bean

of your own of any of the auto-configured types it will replace the default (except in the case of

RedisTemplate

the exclusion is based on the bean name ‘redisTemplate’ not its type). If commons-pool2

is on the classpath you will get a pooled connection factory by default.

31.2 MongoDB

MongoDB is an open-source NoSQL document database that uses a JSON-like schema instead of traditional table-based relational data. Spring Boot offers several conveniences for working with

MongoDB, including the spring-boot-starter-data-mongodb

‘Starter POM’.

Connecting to a MongoDB database

You can inject an auto-configured org.springframework.data.mongodb.MongoDbFactory

to access Mongo databases. By default the instance will attempt to connect to a MongoDB server using the URL mongodb://localhost/test

:

import

org.springframework.data.mongodb.MongoDbFactory;

import

com.mongodb.DB;

@Component

public class

MyBean {

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private final

MongoDbFactory mongo;

@Autowired

public

MyBean(MongoDbFactory mongo) {

this

.mongo = mongo;

}

// ...

public void

example() {

DB db = mongo.getDb();

// ...

}

}

You can set spring.data.mongodb.uri

property to change the URL and configure additional settings such as the replica set:

spring.data.mongodb.uri

=mongodb://user:[email protected]:12345,mongo2.example.com:23456/test

Alternatively, as long as you’re using Mongo 2.x, specify a host

/ port

. For example, you might declare the following in your application.properties

:

spring.data.mongodb.host

=mongoserver

spring.data.mongodb.port

=27017

Note

spring.data.mongodb.host

and spring.data.mongodb.port

are not supported if you’re using the Mongo 3.0 Java driver. In such cases, spring.data.mongodb.uri

should be used to provide all of the configuration.

Tip

If spring.data.mongodb.port

is not specified the default of

27017

is used. You could simply delete this line from the sample above.

Tip

If you aren’t using Spring Data Mongo you can inject com.mongodb.Mongo

beans instead of using

MongoDbFactory

.

You can also declare your own

MongoDbFactory

or

Mongo

bean if you want to take complete control of establishing the MongoDB connection.

MongoTemplate

Spring Data Mongo provides a

MongoTemplate

class that is very similar in its design to Spring’s

JdbcTemplate

. As with

JdbcTemplate

Spring Boot auto-configures a bean for you to simply inject:

import

org.springframework.beans.factory.annotation.Autowired;

import

org.springframework.data.mongodb.core.MongoTemplate;

import

org.springframework.stereotype.Component;

@Component

public class

MyBean {

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private final

MongoTemplate mongoTemplate;

@Autowired

public

MyBean(MongoTemplate mongoTemplate) {

this

.mongoTemplate = mongoTemplate;

}

// ...

}

See the

MongoOperations

Javadoc for complete details.

Spring Data MongoDB repositories

Spring Data includes repository support for MongoDB. As with the JPA repositories discussed earlier, the basic principle is that queries are constructed for you automatically based on method names.

In fact, both Spring Data JPA and Spring Data MongoDB share the same common infrastructure; so you could take the JPA example from earlier and, assuming that

City

is now a Mongo data class rather than a JPA

@Entity

, it will work in the same way.

package

com.example.myapp.domain;

import

org.springframework.data.domain.*;

import

org.springframework.data.repository.*;

public interface

CityRepository

extends

Repository<City, Long> {

Page<City> findAll(Pageable pageable);

City findByNameAndCountryAllIgnoringCase(String name, String country);

}

Tip

For complete details of Spring Data MongoDB, including its rich object mapping technologies, refer to their reference documentation .

Embedded Mongo

Spring Boot offers auto-configuration for Embedded Mongo . To use it in your Spring Boot application add a dependency on de.flapdoodle.embed:de.flapdoodle.embed.mongo

.

The port that Mongo will listen on can be configured using the spring.data.mongodb.port

property. To use a randomly allocated free port use a value of zero. The

MongoClient

created by

MongoAutoConfiguration

will be automatically configured to use the randomly allocated port.

If you have SLF4J on the classpath, output produced by Mongo will be automatically routed to a logger named org.springframework.boot.autoconfigure.mongo.embedded.EmbeddedMongo

.

You can declare your own

IMongodConfig

and

IRuntimeConfig

beans to take control of the Mongo instance’s configuration and logging routing.

31.3 Gemfire

Spring Data Gemfire provides convenient Spring-friendly tools for accessing the Pivotal Gemfire data management platform. There is a spring-boot-starter-data-gemfire

‘Starter POM’

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(

@EnableGemfireRepositories

) .

31.4 Solr

Apache Solr is a search engine. Spring Boot offers basic auto-configuration for the Solr 4 client library and abstractions on top of it provided by Spring Data Solr . There is a spring-boot-starter-datasolr

‘Starter POM’ for collecting the dependencies in a convenient way.

Tip

Solr 5 is currently not supported and the auto-configuration will not be enabled by a Solr 5 dependency.

Connecting to Solr

You can inject an auto-configured

SolrServer

instance as you would any other Spring bean. By default the instance will attempt to connect to a server using localhost:8983/solr

:

@Component

public class

MyBean {

private

SolrServer solr;

@Autowired

public

MyBean(SolrServer solr) {

this

.solr = solr;

}

// ...

}

If you add a

@Bean

of your own of type

SolrServer

it will replace the default.

Spring Data Solr repositories

Spring Data includes repository support for Apache Solr. As with the JPA repositories discussed earlier, the basic principle is that queries are constructed for you automatically based on method names.

In fact, both Spring Data JPA and Spring Data Solr share the same common infrastructure; so you could take the JPA example from earlier and, assuming that

City

is now a

@SolrDocument

class rather than a JPA

@Entity

, it will work in the same way.

Tip

For complete details of Spring Data Solr, refer to their reference documentation .

31.5 Elasticsearch

Elasticsearch is an open source, distributed, real-time search and analytics engine. Spring Boot offers basic auto-configuration for the Elasticsearch and abstractions on top of it provided by Spring

Data Elasticsearch . There is a spring-boot-starter-data-elasticsearch

‘Starter POM’ for collecting the dependencies in a convenient way.

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Connecting to Elasticsearch

You can inject an auto-configured

ElasticsearchTemplate

or Elasticsearch

Client

instance as you would any other Spring Bean. By default the instance will attempt to connect to a local inmemory server (a

NodeClient

in Elasticsearch terms), but you can switch to a remote server (i.e.

a

TransportClient

) by setting spring.data.elasticsearch.cluster-nodes

to a commaseparated ‘host:port’ list.

@Component

public class

MyBean {

private

ElasticsearchTemplate template;

@Autowired

public

MyBean(ElasticsearchTemplate template) {

this

.template = template;

}

// ...

}

If you add a

@Bean

of your own of type

ElasticsearchTemplate

it will replace the default.

Spring Data Elasticsearch repositories

Spring Data includes repository support for Elasticsearch. As with the JPA repositories discussed earlier, the basic principle is that queries are constructed for you automatically based on method names.

In fact, both Spring Data JPA and Spring Data Elasticsearch share the same common infrastructure; so you could take the JPA example from earlier and, assuming that

City

is now an Elasticsearch

@Document

class rather than a JPA

@Entity

, it will work in the same way.

Tip

For complete details of Spring Data Elasticsearch, refer to their reference documentation .

31.6 Cassandra

Cassandra is an open source, distributed database management system designed to handle large amounts of data across many commodity servers. Spring Boot offers auto-configuration for Cassandra and abstractions on top of it provided by Spring Data Cassandra . There is a spring-boot-starterdata-cassandra

‘Starter POM’ for collecting the dependencies in a convenient way.

Connecting to Cassandra

You can inject an auto-configured

CassandraTemplate

or a Cassandra

Session

instance as you would any other Spring Bean. The spring.data.cassandra.*

properties can be used to customize the connection. Generally you will to provide keyspace-name

and contact-points

properties:

spring.data.cassandra.keyspace-name

=mykeyspace

spring.data.cassandra.contact-points

=cassandrahost1,cassandrahost2

@Component

public class

MyBean {

private

CassandraTemplate template;

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@Autowired

public

MyBean(CassandraTemplate template) {

this

.template = template;

}

// ...

}

If you add a

@Bean

of your own of type

CassandraTemplate

it will replace the default.

Spring Data Cassandra repositories

Spring Data includes basic repository support for Cassandra. Currently this is more limited than the JPA repositories discussed earlier, and will need to annotate finder methods with

@Query

.

Tip

For complete details of Spring Data Cassandra, refer to their reference documentation .

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32. Caching

The Spring Framework provides support for transparently adding caching to an application. At its core, the abstraction applies caching to methods, reducing thus the number of executions based on the information available in the cache. The caching logic is applied transparently, without any interference to the invoker.

Note

Check the relevant section of the Spring Framework reference for more details.

In a nutshell, adding caching to an operation of your service is as easy as adding the relevant annotation to its method:

import

javax.cache.annotation.CacheResult;

import

org.springframework.stereotype.Component;

@Component

public class

MathService {

@CacheResult

public int

computePiDecimal(

int

i) {

// ...

}

}

Note

You can either use the standard JSR-107 (JCache) annotations or Spring’s own caching annotations transparently. We strongly advise you however to not mix and match them.

Tip

It is also possible to update or evict data from the cache transparently.

32.1 Supported cache providers

The cache abstraction does not provide an actual store and relies on abstraction materialized by the org.springframework.cache.Cache

and org.springframework.cache.CacheManager

interfaces. Spring Boot auto-configures a suitable

CacheManager

according to the implementation as long as the caching support is enabled via the

@EnableCaching

annotation.

Tip

Use the spring-boot-starter-cache

“Starter POM” to quickly add required caching dependencies. If you are adding dependencies manually you should note that certain implementations are only provided by the spring-context-support

jar.

Spring Boot tries to detect the following providers (in this order):

Generic

JCache (JSR-107)

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EhCache 2.x

Hazelcast

Infinispan

Redis

Guava

Simple

It is also possible to force the cache provider to use via the spring.cache.type

property.

Generic

Generic caching is used if the context defines at least one org.springframework.cache.Cache

bean, a

CacheManager

wrapping them is configured.

JCache

JCache is bootstrapped via the presence of a javax.cache.spi.CachingProvider

on the classpath (i.e. a JSR-107 compliant caching library). It might happen than more that one provider is present, in which case the provider must be explicitly specified. Even if the JSR-107 standard does not enforce a standardized way to define the location of the configuration file, Spring Boot does its best to accommodate with implementation details.

# Only necessary if more than one provider is present

spring.cache.jcache.provider

=com.acme.MyCachingProvider

spring.cache.jcache.config

=classpath:acme.xml

Note

Since a cache library may offer both a native implementation and JSR-107 support Spring Boot will prefer the JSR-107 support so that the same features are available if you switch to a different

JSR-107 implementation.

There are several ways to customize the underlying javax.cache.cacheManager

:

• Caches can be created on startup via the spring.cache.cache-names

property. If a custom javax.cache.configuration.Configuration

bean is defined, it is used to customize them.

• org.springframework.boot.autoconfigure.cache.JCacheManagerCustomizer

beans are invoked with the reference of the

CacheManager

for full customization.

Tip

If a standard javax.cache.CacheManager

bean is defined, it is wrapped automatically in a org.springframework.cache.CacheManager

implementation that the abstraction expects.

No further customization is applied on it.

EhCache 2.x

EhCache 2.x is used if a file named ehcache.xml

can be found at the root of the classpath. If EhCache

2.x and such file is present it is used to bootstrap the cache manager. An alternate configuration file can be provide a well using:

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spring.cache.ehcache.config

=classpath:config/another-config.xml

Hazelcast

Spring Boot has a general support for Hazelcast

. If a

HazelcastInstance

has been auto-configured, it is automatically wrapped in a

CacheManager

.

If for some reason you need a different

HazelcastInstance

for caching, you can request Spring Boot to create a separate one that will be only used by the

CacheManager

:

spring.cache.hazelcast.config

=classpath:config/my-cache-hazelcast.xml

Tip

If a separate

HazelcastInstance

is created that way, it is not registered in the application context.

Infinispan

Infinispan has no default configuration file location so it must be specified explicitly (or the default bootstrap is used).

spring.cache.infinispan.config

=infinispan.xml

Caches can be created on startup via the spring.cache.cache-names

property. If a custom

ConfigurationBuilder

bean is defined, it is used to customize them.

Redis

If Redis is available and configured, the

RedisCacheManager

is auto-configured. It is also possible to create additional caches on startup using the spring.cache.cache-names

property.

Guava

If Guava is present, a

GuavaCacheManager

is auto-configured. Caches can be created on startup using the spring.cache.cache-names

property and customized by one of the following (in this order):

1. A cache spec defined by spring.cache.guava.spec

2. A com.google.common.cache.CacheBuilderSpec

bean is defined

3. A com.google.common.cache.CacheBuilder

bean is defined

For instance, the following configuration creates a foo

and bar

caches with a maximum size of 500 and a time to live of 10 minutes

spring.cache.cache-names

=foo,bar

spring.cache.guava.spec

=maximumSize=500,expireAfterAccess=600s

Besides, if a com.google.common.cache.CacheLoader

bean is defined, it is automatically associated to the

GuavaCacheManager

.

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Simple

If none of these options worked out, a simple implementation using

ConcurrentHashMap

as cache store is configured. This is the default if no caching library is present in your application.

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33. Messaging

The Spring Framework provides extensive support for integrating with messaging systems: from simplified use of the JMS API using

JmsTemplate

to a complete infrastructure to receive messages asynchronously. Spring AMQP provides a similar feature set for the ‘Advanced Message Queuing

Protocol’ and Spring Boot also provides auto-configuration options for

RabbitTemplate

and

RabbitMQ. There is also support for STOMP messaging natively in Spring WebSocket and Spring Boot has support for that through starters and a small amount of auto-configuration.

33.1 JMS

The javax.jms.ConnectionFactory

interface provides a standard method of creating a javax.jms.Connection

for interacting with a JMS broker. Although Spring needs a

ConnectionFactory

to work with JMS, you generally won’t need to use it directly yourself and you can instead rely on higher level messaging abstractions (see the relevant section of the Spring Framework reference documentation for details). Spring Boot also auto-configures the necessary infrastructure to send and receive messages.

ActiveMQ support

Spring Boot can also configure a

ConnectionFactory

when it detects that ActiveMQ is available on the classpath. If the broker is present, an embedded broker is started and configured automatically (as long as no broker URL is specified through configuration).

ActiveMQ configuration is controlled by external configuration properties in spring.activemq.*

. For example, you might declare the following section in application.properties

:

spring.activemq.broker-url

=tcp://192.168.1.210:9876

spring.activemq.user

=admin

spring.activemq.password

=secret

See

ActiveMQProperties

for more of the supported options.

By default, ActiveMQ creates a destination if it does not exist yet, so destinations are resolved against their provided names.

Artemis support

Apache Artemis was formed in 2015 when HornetQ was donated to the Apache Foundation. All the features listed in the

the section called “HornetQ support” section below can be applied to Artemis.

Simply replace spring.hornetq.*

properties with spring.artemis.*

and use spring-bootstarter-artemis

instead of spring-boot-starter-hornetq

.

Note

You should not try and use Artemis and HornetQ and the same time.

HornetQ support

Spring Boot can auto-configure a

ConnectionFactory

when it detects that HornetQ is available on the classpath. If the broker is present, an embedded broker is started and configured automatically

(unless the mode property has been explicitly set). The supported modes are: embedded

(to make

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to connect to a broker using the netty

transport protocol. When the latter is configured, Spring Boot configures a

ConnectionFactory

connecting to a broker running on the local machine with the default settings.

Note

If you are using spring-boot-starter-hornetq

the necessary dependencies to connect to an existing HornetQ instance are provided, as well as the Spring infrastructure to integrate with

JMS. Adding org.hornetq:hornetq-jms-server

to your application allows you to use the embedded mode.

HornetQ configuration is controlled by external configuration properties in spring.hornetq.*

. For example, you might declare the following section in application.properties

:

spring.hornetq.mode

=native

spring.hornetq.host

=192.168.1.210

spring.hornetq.port

=9876

When embedding the broker, you can choose if you want to enable persistence, and the list of destinations that should be made available. These can be specified as a comma-separated list to create them with the default options; or you can define bean(s) of type org.hornetq.jms.server.config.JMSQueueConfiguration

or org.hornetq.jms.server.config.TopicConfiguration

, for advanced queue and topic configurations respectively.

See

HornetQProperties

for more of the supported options.

No JNDI lookup is involved at all and destinations are resolved against their names, either using the

‘name’ attribute in the HornetQ configuration or the names provided through configuration.

Using a JNDI ConnectionFactory

If you are running your application in an Application Server Spring Boot will attempt to locate a JMS

ConnectionFactory

using JNDI. By default the locations java:/JmsXA

and java:/

XAConnectionFactory

will be checked. You can use the spring.jms.jndi-name

property if you need to specify an alternative location:

spring.jms.jndi-name

=java:/MyConnectionFactory

Sending a message

Spring’s

JmsTemplate

is auto-configured and you can autowire it directly into your own beans:

import

org.springframework.beans.factory.annotation.Autowired;

import

org.springframework.jms.core.JmsTemplate;

import

org.springframework.stereotype.Component;

@Component

public class

MyBean {

private final

JmsTemplate jmsTemplate;

@Autowired

public

MyBean(JmsTemplate jmsTemplate) {

this

.jmsTemplate = jmsTemplate;

}

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// ...

}

Note

JmsMessagingTemplate

can be injected in a similar manner.

Receiving a message

When the JMS infrastructure is present, any bean can be annotated with

@JmsListener

to create a listener endpoint. If no

JmsListenerContainerFactory

has been defined, a default one is configured automatically.

The default factory is transactional by default. If you are running in an infrastructure where a

JtaTransactionManager

is present, it will be associated to the listener container by default. If not, the sessionTransacted

flag will be enabled. In that latter scenario, you can associate your local data store transaction to the processing of an incoming message by adding

@Transactional

on your listener method (or a delegate thereof). This will make sure that the incoming message is acknowledged once the local transaction has completed. This also includes sending response messages that have been performed on the same JMS session.

The following component creates a listener endpoint on the someQueue

destination:

@Component

public class

MyBean {

@JmsListener(destination = "someQueue")

public void

processMessage(String content) {

// ...

}

}

Tip

Check the Javadoc of

@EnableJms

for more details.

33.2 AMQP

The Advanced Message Queuing Protocol (AMQP) is a platform-neutral, wire-level protocol for message-oriented middleware. The Spring AMQP project applies core Spring concepts to the development of AMQP-based messaging solutions.

RabbitMQ support

RabbitMQ is a lightweight, reliable, scalable and portable message broker based on the AMQP protocol.

Spring uses

RabbitMQ

to communicate using the AMQP protocol.

RabbitMQ configuration is controlled by external configuration properties in spring.rabbitmq.*

. For example, you might declare the following section in application.properties

:

spring.rabbitmq.host

=localhost

spring.rabbitmq.port

=5672

spring.rabbitmq.username

=admin

spring.rabbitmq.password

=secret

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See

RabbitProperties

for more of the supported options.

Tip

Check Understanding AMQP, the protocol used by RabbitMQ for more details.

Sending a message

Spring’s

AmqpTemplate

and

AmqpAdmin

are auto-configured and you can autowire them directly into your own beans:

import

org.springframework.amqp.core.AmqpAdmin;

import

org.springframework.amqp.core.AmqpTemplate;

import

org.springframework.beans.factory.annotation.Autowired;

import

org.springframework.stereotype.Component;

@Component

public class

MyBean {

private final

AmqpAdmin amqpAdmin;

private final

AmqpTemplate amqpTemplate;

@Autowired

public

MyBean(AmqpAdmin amqpAdmin, AmqpTemplate amqpTemplate) {

this

.amqpAdmin = amqpAdmin;

this

.amqpTemplate = amqpTemplate;

}

// ...

}

Note

RabbitMessagingTemplate

can be injected in a similar manner.

Any org.springframework.amqp.core.Queue

that is defined as a bean will be automatically used to declare a corresponding queue on the RabbitMQ instance if necessary.

Receiving a message

When the Rabbit infrastructure is present, any bean can be annotated with

@RabbitListener

to create a listener endpoint. If no

RabbitListenerContainerFactory

has been defined, a default one is configured automatically.

The following component creates a listener endpoint on the someQueue

queue:

@Component

public class

MyBean {

@RabbitListener(queues = "someQueue")

public void

processMessage(String content) {

// ...

}

}

Tip

Check the Javadoc of

@EnableRabbit

for more details.

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34. Sending email

The Spring Framework provides an easy abstraction for sending email using the

JavaMailSender interface and Spring Boot provides auto-configuration for it as well as a starter module.

Tip

Check the reference documentation for a detailed explanation of how you can use

JavaMailSender

.

If spring.mail.host

and the relevant libraries (as defined by spring-boot-starter-mail

) are available, a default

JavaMailSender

is created if none exists. The sender can be further customized by configuration items from the spring.mail

namespace, see the

MailProperties

for more details.

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35. Distributed Transactions with JTA

Spring Boot supports distributed JTA transactions across multiple XA resources using either an

Atomikos or Bitronix embedded transaction manager. JTA transactions are also supported when deploying to a suitable Java EE Application Server.

When a JTA environment is detected, Spring’s

JtaTransactionManager

will be used to manage transactions. Auto-configured JMS, DataSource and JPA beans will be upgraded to support XA transactions. You can use standard Spring idioms such as

@Transactional

to participate in a distributed transaction. If you are within a JTA environment and still want to use local transactions you can set the spring.jta.enabled

property to false

to disable the JTA auto-configuration.

35.1 Using an Atomikos transaction manager

Atomikos is a popular open source transaction manager which can be embedded into your Spring Boot application. You can use the spring-boot-starter-jta-atomikos

Starter POM to pull in the appropriate Atomikos libraries. Spring Boot will auto-configure Atomikos and ensure that appropriate depends-on

settings are applied to your Spring beans for correct startup and shutdown ordering.

By default Atomikos transaction logs will be written to a transaction-logs

directory in your application home directory (the directory in which your application jar file resides).

You can customize this directory by setting a spring.jta.log-dir

property in your application.properties

file. Properties starting spring.jta.

can also be used to customize the

Atomikos

UserTransactionServiceImp

. See the

AtomikosProperties

Javadoc for complete details.

Note

To ensure that multiple transaction managers can safely coordinate the same resource managers, each Atomikos instance must be configured with a unique ID. By default this ID is the IP address of the machine on which Atomikos is running. To ensure uniqueness in production, you should configure the spring.jta.transaction-manager-id

property with a different value for each instance of your application.

35.2 Using a Bitronix transaction manager

Bitronix is another popular open source JTA transaction manager implementation. You can use the spring-boot-starter-jta-bitronix

starter POM to add the appropriate Bitronix dependencies to your project. As with Atomikos, Spring Boot will automatically configure Bitronix and post-process your beans to ensure that startup and shutdown ordering is correct.

By default Bitronix transaction log files ( part1.btm

and part2.btm

) will be written to a transaction-logs

directory in your application home directory. You can customize this directory by using the spring.jta.log-dir

property. Properties starting spring.jta.

are also bound to the bitronix.tm.Configuration

bean, allowing for complete customization. See the Bitronix documentation for details.

Note

To ensure that multiple transaction managers can safely coordinate the same resource managers, each Bitronix instance must be configured with a unique ID. By default this ID is the IP address

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property with a different value for each instance of your application.

35.3 Using a Java EE managed transaction manager

If you are packaging your Spring Boot application as a war

or ear

file and deploying it to a Java

EE application server, you can use your application servers built-in transaction manager. Spring

Boot will attempt to auto-configure a transaction manager by looking at common JNDI locations

( java:comp/UserTransaction

, java:comp/TransactionManager

etc). If you are using a transaction service provided by your application server, you will generally also want to ensure that all resources are managed by the server and exposed over JNDI. Spring Boot will attempt to auto-configure JMS by looking for a

ConnectionFactory

at the JNDI path java:/JmsXA

or java:/XAConnectionFactory

and you can use the

spring.datasource.jndi-name

property

to configure your

DataSource

.

35.4 Mixing XA and non-XA JMS connections

When using JTA, the primary JMS

ConnectionFactory

bean will be XA aware and participate in distributed transactions. In some situations you might want to process certain JMS messages using a non-XA

ConnectionFactory

. For example, your JMS processing logic might take longer than the

XA timeout.

If you want to use a non-XA

ConnectionFactory

you can inject the nonXaJmsConnectionFactory bean rather than the

@Primary jmsConnectionFactory

bean. For consistency the jmsConnectionFactory

bean is also provided using the bean alias xaJmsConnectionFactory

.

For example:

// Inject the primary (XA aware) ConnectionFactory

@Autowired

private

ConnectionFactory defaultConnectionFactory;

// Inject the XA aware ConnectionFactory (uses the alias and injects the same as above)

@Autowired

@Qualifier("xaJmsConnectionFactory")

private

ConnectionFactory xaConnectionFactory;

// Inject the non-XA aware ConnectionFactory

@Autowired

@Qualifier("nonXaJmsConnectionFactory")

private

ConnectionFactory nonXaConnectionFactory;

35.5 Supporting an alternative embedded transaction manager

The

XAConnectionFactoryWrapper

and

XADataSourceWrapper

interfaces can be used to support alternative embedded transaction managers. The interfaces are responsible for wrapping

XAConnectionFactory

and

XADataSource

beans and exposing them as regular

ConnectionFactory

and

DataSource

beans which will transparently enroll in the distributed transaction. DataSource and JMS auto-configuration will use JTA variants as long as you have a

JtaTransactionManager

bean and appropriate XA wrapper beans registered within your

ApplicationContext

.

The BitronixXAConnectionFactoryWrapper and BitronixXADataSourceWrapper provide good examples of how to write XA wrappers.

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36. Hazelcast

If hazelcast is on the classpath, Spring Boot will auto-configure an

HazelcastInstance

that you can inject in your application. The

HazelcastInstance

is only created if a configuration is found.

You can define a com.hazelcast.config.Config

bean and we’ll use that. If your configuration defines an instance name, we’ll try to locate an existing instance rather than creating a new one.

You could also specify the hazelcast.xml

configuration file to use via configuration:

spring.hazelcast.config

=classpath:config/my-hazelcast.xml

Otherwise, Spring Boot tries to find the Hazelcast configuration from the default locations, that is hazelcast.xml

in the working directory or at the root of the classpath. We also check if the hazelcast.config

system property is set. Check the Hazelcast documentation for more details.

Note

Spring Boot also has an

explicit caching support for Hazelcast . The

HazelcastInstance

is automatically wrapped in a

CacheManager

implementation if caching is enabled.

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37. Spring Integration

Spring Integration provides abstractions over messaging and also other transports such as HTTP, TCP etc. If Spring Integration is available on your classpath it will be initialized through the

@EnableIntegration

annotation. Message processing statistics will be published over JMX if

'spring-integration-jmx'

is also on the classpath. See the

IntegrationAutoConfiguration

class for more details.

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38. Spring Session

Spring Session provides support for managing a user’s session information. If you are writing a web application and Spring Session and Spring Data Redis are both on the classpath, Spring Boot will autoconfigure Spring Session through its

@EnableRedisHttpSession

. Session data will be stored in

Redis and the session timeout can be configured using the server.session.timeout

property.

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39. Monitoring and management over JMX

Java Management Extensions (JMX) provide a standard mechanism to monitor and manage applications. By default Spring Boot will create an

MBeanServer

with bean id ‘mbeanServer’ and expose any of your beans that are annotated with Spring JMX annotations (

@ManagedResource

,

@ManagedAttribute

,

@ManagedOperation

).

See the

JmxAutoConfiguration

class for more details.

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40. Testing

Spring Boot provides a number of useful tools for testing your application. The spring-bootstarter-test

POM provides Spring Test, JUnit, Hamcrest and Mockito dependencies. There are also useful test utilities in the core spring-boot

module under the org.springframework.boot.test

package.

40.1 Test scope dependencies

If you use the spring-boot-starter-test

‘Starter POM’ (in the test scope

), you will find the following provided libraries:

• Spring Test — integration test support for Spring applications.

• JUnit — The de-facto standard for unit testing Java applications.

• Hamcrest — A library of matcher objects (also known as constraints or predicates) allowing assertThat

style JUnit assertions.

• Mockito — A Java mocking framework.

These are common libraries that we generally find useful when writing tests. You are free to add additional test dependencies of your own if these don’t suit your needs.

40.2 Testing Spring applications

One of the major advantages of dependency injection is that it should make your code easier to unit test. You can simply instantiate objects using the new

operator without even involving Spring. You can also use mock objects instead of real dependencies.

Often you need to move beyond ‘unit testing’ and start ‘integration testing’ (with a Spring

ApplicationContext

actually involved in the process). It’s useful to be able to perform integration testing without requiring deployment of your application or needing to connect to other infrastructure.

The Spring Framework includes a dedicated test module for just such integration testing. You can declare a dependency directly to org.springframework:spring-test

or use the spring-bootstarter-test

‘Starter POM’ to pull it in transitively.

If you have not used the spring-test

module before you should start by reading the relevant section of the Spring Framework reference documentation.

40.3 Testing Spring Boot applications

A Spring Boot application is just a Spring

ApplicationContext

so nothing very special has to be done to test it beyond what you would normally do with a vanilla Spring context. One thing to watch out for though is that the external properties, logging and other features of Spring Boot are only installed in the context by default if you use

SpringApplication

to create it.

Spring Boot provides a

@SpringApplicationConfiguration

annotation as an alternative to the standard spring-test @ContextConfiguration annotation. If you use

@SpringApplicationConfiguration

to configure the

ApplicationContext

used in your tests, it will be created via

SpringApplication

and you will get the additional Spring Boot features.

For example:

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@RunWith(SpringJUnit4ClassRunner.class)

@SpringApplicationConfiguration(SampleDataJpaApplication.class)

public class

CityRepositoryIntegrationTests {

@Autowired

CityRepository repository;

// ...

}

Tip

The context loader guesses whether you want to test a web application or not (e.g.

with

MockMvc

) by looking for the

@WebIntegrationTest

or

@WebAppConfiguration annotations. (

MockMvc

and

@WebAppConfiguration

are part of spring-test

).

If you want a web application to start up and listen on its normal port, so you can test it with

HTTP (e.g. using

RestTemplate

), annotate your test class (or one of its superclasses) with

@WebIntegrationTest

. This can be very useful because it means you can test the full stack of your application, but also inject its components into the test class and use them to assert the internal state of the application after an HTTP interaction. For example:

@RunWith(SpringJUnit4ClassRunner.class)

@SpringApplicationConfiguration(SampleDataJpaApplication.class)

@WebIntegrationTest

public class

CityRepositoryIntegrationTests {

@Autowired

CityRepository repository;

RestTemplate restTemplate =

new

TestRestTemplate();

// ... interact with the running server

}

Note

Spring’s test framework will cache application contexts between tests. Therefore, as long as your tests share the same configuration, the time consuming process of starting and stopping the server will only happen once, regardless of the number of tests that actually run.

To change the port you can add environment properties to

@WebIntegrationTest

as colonor equals-separated name-value pairs, e.g.

@WebIntegrationTest("server.port:9000")

.

Additionally you can set the server.port

and management.port

properties to

0

in order to run your integration tests using random ports. For example:

@RunWith(SpringJUnit4ClassRunner.class)

@SpringApplicationConfiguration(MyApplication.class)

@WebIntegrationTest({"server.port=0", "management.port=0"})

public class

SomeIntegrationTests {

// ...

}

Alternatively, you can use the randomPort

convenience attribute to set server.port=0

. For example:

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@RunWith(SpringJUnit4ClassRunner.class)

@SpringApplicationConfiguration(MyApplication.class)

@WebIntegrationTest(randomPort = true)

public class

SomeIntegrationTests {

// ...

}

See

Section 70.4, “Discover the HTTP port at runtime” for a description of how you can discover the

actual port that was allocated for the duration of the tests.

Using Spock to test Spring Boot applications

If you wish to use Spock to test a Spring Boot application you should add a dependency on Spock’s spock-spring

module to your application’s build. spock-spring

integrates Spring’s test framework into Spock.

Note

The annotations

described above

can be used with Spock, i.e. you can annotate your

Specification

with

@WebIntegrationTest

to suit the needs of your tests.

40.4 Test utilities

A few test utility classes are packaged as part of spring-boot

that are generally useful when testing your application.

ConfigFileApplicationContextInitializer

ConfigFileApplicationContextInitializer

is an

ApplicationContextInitializer

that can apply to your tests to load Spring Boot application.properties

files. You can use this when you don’t need the full features provided by

@SpringApplicationConfiguration

.

@ContextConfiguration(classes = Config.

class

,

initializers = ConfigFileApplicationContextInitializer.

class

)

EnvironmentTestUtils

EnvironmentTestUtils

allows you to quickly add properties to a

ConfigurableEnvironment

or

ConfigurableApplicationContext

. Simply call it with key=value

strings:

EnvironmentTestUtils.addEnvironment(env,

"org=Spring"

,

"name=Boot"

);

OutputCapture

OutputCapture

is a JUnit

Rule

that you can use to capture

System.out

and

System.err

output.

Simply declare the capture as a

@Rule

then use toString()

for assertions:

import

org.junit.Rule;

import

org.junit.Test;

import

org.springframework.boot.test.OutputCapture;

import static

org.hamcrest.Matchers.*;

import static

org.junit.Assert.*;

public class

MyTest {

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@Rule

public

OutputCapture capture =

new

OutputCapture();

@Test

public void

testName()

throws

Exception {

System.out.println(

"Hello World!"

);

assertThat(capture.toString(), containsString(

"World"

));

}

}

TestRestTemplate

TestRestTemplate

is a convenience subclass of Spring’s

RestTemplate

that is useful in integration tests. You can get a vanilla template or one that sends Basic HTTP authentication (with a username and password). In either case the template will behave in a test-friendly way: not following redirects (so you can assert the response location), ignoring cookies (so the template is stateless), and not throwing exceptions on server-side errors. It is recommended, but not mandatory, to use Apache HTTP Client

(version 4.3.2 or better), and if you have that on your classpath the

TestRestTemplate

will respond by configuring the client appropriately.

public class

MyTest {

RestTemplate template =

new

TestRestTemplate();

@Test

public void

testRequest()

throws

Exception {

HttpHeaders headers = template.getForEntity(

"http://myhost.com"

, String.

class

).getHeaders();

assertThat(headers.getLocation().toString(), containsString(

"myotherhost"

));

}

}

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41. Creating your own auto-configuration

If you work in a company that develops shared libraries, or if you work on an open-source or commercial library, you might want to develop your own auto-configuration. Auto-configuration classes can be bundled in external jars and still be picked-up by Spring Boot.

Auto-configuration can be associated to a "starter" that provides the auto-configuration code as well as the typical libraries that you would use with it. We will first cover what you need to know to build your own auto-configuration and we will move on to the

typical steps required to create a custom starter .

Tip

A demo project is available to showcase how you can create a starter step by step.

41.1 Understanding auto-configured beans

Under the hood, auto-configuration is implemented with standard

@Configuration

classes. Additional

@Conditional

annotations are used to constrain when the auto-configuration should apply. Usually auto-configuration classes use

@ConditionalOnClass

and

@ConditionalOnMissingBean annotations. This ensures that auto-configuration only applies when relevant classes are found and when you have not declared your own

@Configuration

.

You can browse the source code of spring-boot-autoconfigure

to see the

@Configuration classes that we provide (see the

META-INF/spring.factories

file).

41.2 Locating auto-configuration candidates

Spring Boot checks for the presence of a

META-INF/spring.factories

file within your published jar. The file should list your configuration classes under the

EnableAutoConfiguration

key.

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\ com.mycorp.libx.autoconfigure.LibXAutoConfiguration,\ com.mycorp.libx.autoconfigure.LibXWebAutoConfiguration

You can use the

@AutoConfigureAfter

or

@AutoConfigureBefore

annotations if your configuration needs to be applied in a specific order. For example, if you provide web-specific configuration, your class may need to be applied after

WebMvcAutoConfiguration

.

If you want to order certain auto-configurations that shouldn’t have any direct knowledge of each other, you can also use

@AutoconfigureOrder

. That annotation has the same semantic as the regular

@Order

annotation but provides a dedicated order for auto-configuration classes.

41.3 Condition annotations

You almost always want to include one or more

@Conditional

annotations on your auto-configuration class. The

@ConditionalOnMissingBean

is one common example that is used to allow developers to ‘override’ auto-configuration if they are not happy with your defaults.

Spring Boot includes a number of

@Conditional

annotations that you can reuse in your own code by annotating

@Configuration

classes or individual

@Bean

methods.

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Class conditions

The

@ConditionalOnClass and

@ConditionalOnMissingClass annotations allows configuration to be included based on the presence or absence of specific classes. Due to the fact that annotation metadata is parsed using ASM you can actually use the value

attribute to refer to the real class, even though that class might not actually appear on the running application classpath. You can also use the name

attribute if you prefer to specify the class name using a

String

value.

Bean conditions

The

@ConditionalOnBean

and

@ConditionalOnMissingBean

annotations allow a bean to be included based on the presence or absence of specific beans. You can use the value

attribute to specify beans by type, or name

to specify beans by name. The search

attribute allows you to limit the

ApplicationContext

hierarchy that should be considered when searching for beans.

Tip

You need to be very careful about the order that bean definitions are added as these conditions are evaluated based on what has been processed so far. For this reason, we recommend only using

@ConditionalOnBean

and

@ConditionalOnMissingBean

annotations on autoconfiguration classes (since these are guaranteed to load after any user-define beans definitions have been added).

Note

@ConditionalOnBean and

@ConditionalOnMissingBean do not prevent

@Configuration

classes from being created. Using these conditions at the class level is equivalent to marking each contained

@Bean

method with the annotation.

Property conditions

The

@ConditionalOnProperty

annotation allows configuration to be included based on a Spring

Environment property. Use the prefix

and name

attributes to specify the property that should be checked. By default any property that exists and is not equal to false

will be matched. You can also create more advanced checks using the havingValue

and matchIfMissing

attributes.

Resource conditions

The

@ConditionalOnResource

annotation allows configuration to be included only when a specific resource is present. Resources can be specified using the usual Spring conventions, for example, file:/home/user/test.dat

.

Web application conditions

The

@ConditionalOnWebApplication

and

@ConditionalOnNotWebApplication

annotations allow configuration to be included depending on whether the application is a 'web application'. A web application is any application that is using a Spring

WebApplicationContext

, defines a session scope or has a

StandardServletEnvironment

.

SpEL expression conditions

The

@ConditionalOnExpression

annotation allows configuration to be included based on the result of a SpEL expression .

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41.4 Creating your own starter

A full Spring Boot starter for a library may contain the following components:

• The autoconfigure

module that contains the auto-configuration code.

• The starter

module that provides a dependency to the autoconfigure module as well as the library and any additional dependencies that are typically useful. In a nutshell, adding the starter should be enough to start using that library.

Tip

You may combine the auto-configuration code and the dependency management in a single module if you don’t need to separate those two concerns.

Naming

Please make sure to provide a proper namespace for your starter. Do not start your module names with spring-boot

, even if you are using a different Maven groupId. We may offer an official support for the thing you’re auto-configuring in the future.

Here is a rule of thumb. Let’s assume that you are creating a starter for "acme", name the auto-configure module acme-spring-boot-autoconfigure

and the starter acme-spring-boot-starter

. If you only have one module combining the two, use acme-spring-boot-starter

.

Besides, if your starter provides configuration keys, use a proper namespace for them. In particular, do not include your keys in the namespaces that Spring Boot uses (e.g. server

, management

, spring

, etc). These are "ours" and we may improve/modify them in the future in such a way it could break your things.

Make sure to

trigger meta-data generation

so that IDE assistance is available for your keys as well. You may want to review the generated meta-data (

META-INF/spring-configurationmetadata.json

) to make sure your keys are properly documented.

Autoconfigure module

The autoconfigure module contains everything that is necessary to get started with the library. It may also contain configuration keys definition (

@ConfigurationProperties

) and any callback interface that can be used to further customize how the components are initialized.

Tip

You should mark the dependencies to the library as optional so that you can include the autoconfigure module in your projects more easily. If you do it that way, the library won’t be provided and Spring Boot will back off by default.

Starter module

The starter is an empty jar, really. Its only purpose is to provide the necessary dependencies to work with the library; see it as an opinionated view of what is required to get started.

Do not make assumptions about the project in which your starter is added. If the library you are autoconfiguring typically requires other starters, mention them as well. Providing a proper set of default

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42. WebSockets

Spring Boot provides WebSockets auto-configuration for embedded Tomcat (8 and 7), Jetty 9 and

Undertow. If you’re deploying a war file to a standalone container, Spring Boot assumes that the container will be responsible for the configuration of its WebSocket support.

Spring Framework provides rich WebSocket support that can be easily accessed via the springboot-starter-websocket

module.

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43. What to read next

If you want to learn more about any of the classes discussed in this section you can check out the Spring

Boot API documentation or you can browse the source code directly . If you have specific questions,

take a look at the how-to

section.

If you are comfortable with Spring Boot’s core features, you can carry on and read about

productionready features .

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Part V. Spring Boot Actuator:

Production-ready features

Spring Boot includes a number of additional features to help you monitor and manage your application when it’s pushed to production. You can choose to manage and monitor your application using HTTP endpoints, with JMX or even by remote shell (SSH or Telnet). Auditing, health and metrics gathering can be automatically applied to your application.

Actuator HTTP endpoints are only available with a Spring MVC-based application. In particular, it will

not work with Jersey unless you enable Spring MVC as well.

Spring Boot Reference Guide

44. Enabling production-ready features

The spring-boot-actuator

module provides all of Spring Boot’s production-ready features. The simplest way to enable the features is to add a dependency to the spring-boot-starter-actuator

‘Starter POM’.

Definition of Actuator

An actuator is a manufacturing term, referring to a mechanical device for moving or controlling something. Actuators can generate a large amount of motion from a small change.

To add the actuator to a Maven based project, add the following ‘starter’ dependency:

<dependencies>

<dependency>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter-actuator

</artifactId>

</dependency>

</dependencies>

For Gradle, use the declaration: dependencies {

compile(

"org.springframework.boot:spring-boot-starter-actuator"

)

}

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45. Endpoints

Actuator endpoints allow you to monitor and interact with your application. Spring Boot includes a number of built-in endpoints and you can also add your own. For example the health

endpoint provides basic application health information.

The way that endpoints are exposed will depend on the type of technology that you choose. Most applications choose HTTP monitoring, where the ID of the endpoint is mapped to a URL. For example, by default, the health

endpoint will be mapped to

/health

.

The following endpoints are available:

ID

actuator autoconfig beans configprops docs dump env flyway health info liquibase logfile metrics

Description Sensitive

Default

true Provides a hypermedia-based “discovery page” for the other endpoints. Requires Spring HATEOAS to be on the classpath.

Displays an auto-configuration report showing all autoconfiguration candidates and the reason why they ‘were’ or

‘were not’ applied.

true

Displays a complete list of all the Spring beans in your application.

true

Displays a collated list of all

@ConfigurationProperties

.

true false Displays documentation, including example requests and responses, for the Actuator’s endpoints. Requires springboot-actuator-docs

to be on the classpath.

true true

Performs a thread dump.

Exposes properties from Spring’s

ConfigurableEnvironment

.

Shows any Flyway database migrations that have been applied.

Shows application health information (when the application is secure, a simple ‘status’ when accessed over an unauthenticated connection or full message details when authenticated).

true false

Displays arbitrary application info.

Shows any Liquibase database migrations that have been applied.

false true

Returns the contents of the logfile (if logging.file

or logging.path

properties have been set). Only available via

MVC.

true

Shows ‘metrics’ information for the current application.

true

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ID

mappings shutdown trace

Description Sensitive

Default

true Displays a collated list of all

@RequestMapping

paths.

Allows the application to be gracefully shutdown (not enabled by default).

true

Displays trace information (by default the last few HTTP requests).

true

Note

Depending on how an endpoint is exposed, the sensitive

property may be used as a security hint. For example, sensitive endpoints will require a username/password when they are accessed over HTTP (or simply disabled if web security is not enabled).

45.1 Customizing endpoints

Endpoints can be customized using Spring properties. You can change if an endpoint is enabled

, if it is considered sensitive

and even its id

.

For example, here is an application.properties

that changes the sensitivity and id of the beans endpoint and also enables shutdown

.

endpoints.beans.id

=springbeans

endpoints.beans.sensitive

=false

endpoints.shutdown.enabled

=true

Note

The prefix # endpoints

+

.

+ name

” is used to uniquely identify the endpoint that is being configured.

By default, all endpoints except for shutdown

are enabled. If you prefer to specifically “opt-in” endpoint enablement you can use the endpoints.enabled

property. For example, the following will disable

all endpoints except for info

:

endpoints.enabled

=false

endpoints.info.enabled

=true

Likewise, you can also choose to globally set the “sensitive” flag of all endpoints. By default, the sensitive flag depends on the type of endpoint (see the table above). For example, to mark all endpoints as sensitive except info

:

endpoints.sensitive

=true

endpoints.info.sensitive

=false

45.2 Hypermedia for actuator MVC endpoints

If Spring HATEOAS is on the classpath (e.g. through the spring-boot-starter-hateoas

or if you are using Spring Data REST ) then the HTTP endpoints from the Actuator are enhanced with hypermedia links, and a “discovery page” is added with links to all the endpoints. The “discovery page” is available on

/actuator

by default. It is implemented as an endpoint, allowing properties

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) and whether or not it is enabled

( endpoints.actuator.enabled

).

When a custom management context path is configured, the “discovery page” will automatically move from

/actuator

to the root of the management context. For example, if the management context path is

/management

then the discovery page will be available from

/management

.

If the HAL Browser is on the classpath via its webjar ( org.webjars:hal-browser

), or via the spring-data-rest-hal-browser

then an HTML “discovery page”, in the form of the HAL Browser, is also provided.

45.3 CORS support

Cross-origin resource sharing (CORS) is a W3C specification that allows you to specify in a flexible way what kind of cross domain requests are authorized. Actuator’s MVC endpoints can be configured to support such scenarios.

CORS support is disabled by default and is only enabled once the endpoints.cors.allowedorigins

property has been set. The configuration below permits

GET

and

POST

calls from the example.com

domain:

endpoints.cors.allowed-origins

=http://example.com

endpoints.cors.allowed-methods

=GET,POST

Tip

Check EndpointCorsProperties for a complete list of options.

45.4 Adding custom endpoints

If you add a

@Bean

of type

Endpoint

then it will automatically be exposed over JMX and HTTP (if there is an server available). An HTTP endpoints can be customized further by creating a bean of type

MvcEndpoint

. Your

MvcEndpoint

is not a

@Controller

but it can use

@RequestMapping

(and

@Managed*

) to expose resources.

Tip

If you are doing this as a library feature consider adding a configuration class to

/META-INF/spring.factories

under the key org.springframework.boot.actuate.autoconfigure.EndpointWebMvcConfiguration

.

If you do that then the endpoint will move to a child context with all the other MVC endpoints if your users ask for a separate management port or address. A configuration declared this way can be a

WebConfigurerAdapter

if it wants to add static resources (for instance) to the management endpoints.

45.5 Health information

Health information can be used to check the status of your running application. It is often used by monitoring software to alert someone if a production system goes down. The default information exposed by the health

endpoint depends on how it is accessed. For an unauthenticated connection in a secure application a simple ‘status’ message is returned, and for an authenticated connection additional details

are also displayed (see Section 46.6, “HTTP health endpoint access restrictions” for HTTP details).

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Health information is collected from all

HealthIndicator

beans defined in your

ApplicationContext

. Spring Boot includes a number of auto-configured

HealthIndicators

and you can also write your own.

45.6 Security with HealthIndicators

Information returned by

HealthIndicators

is often somewhat sensitive in nature. For example, you probably don’t want to publish details of your database server to the world. For this reason, by default, only the health status is exposed over an unauthenticated HTTP connection. If you are happy for complete health information to always be exposed you can set endpoints.health.sensitive

to false

.

Health responses are also cached to prevent “denial of service” attacks. Use the endpoints.health.time-to-live

property if you want to change the default cache period of 1000 milliseconds.

Auto-configured HealthIndicators

The following

HealthIndicators

are auto-configured by Spring Boot when appropriate:

Name Description

DataSourceHealthIndicator DataSource

can be obtained.

Tip

It is possible to disable them all using the management.health.defaults.enabled

property.

Writing custom HealthIndicators

To provide custom health information you can register Spring beans that implement the

HealthIndicator

interface. You need to provide an implementation of the health()

method and return a

Health

response. The

Health

response should include a status and can optionally include additional details to be displayed.

import

org.springframework.boot.actuate.health.HealthIndicator;

import

org.springframework.stereotype.Component;

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@Component

public class

MyHealthIndicator

implements

HealthIndicator {

@Override

public

Health health() {

int

errorCode = check();

// perform some specific health check

if

(errorCode != 0) {

return

Health.down().withDetail(

"Error Code"

, errorCode).build();

}

return

Health.up().build();

}

}

Note

The identifier for a given

HealthIndicator

is the name of the bean without the

HealthIndicator

suffix if it exists. In the example above, the health information will be available in an entry named my

.

In addition to Spring Boot’s predefined

Status

types, it is also possible for

Health

to return a custom

Status

that represents a new system state. In such cases a custom implementation of the

HealthAggregator

interface also needs to be provided, or the default implementation has to be configured using the management.health.status.order

configuration property.

For example, assuming a new

Status

with code

FATAL

is being used in one of your

HealthIndicator

implementations. To configure the severity order add the following to your application properties:

management.health.status.order

=DOWN, OUT_OF_SERVICE, UNKNOWN, UP

You might also want to register custom status mappings with the

HealthMvcEndpoint if you access the health endpoint over HTTP. For example you could map

FATAL

to

HttpStatus.SERVICE_UNAVAILABLE

.

45.7 Custom application info information

You can customize the data exposed by the info

endpoint by setting info.*

Spring properties. All

Environment

properties under the info key will be automatically exposed. For example, you could add the following to your application.properties

:

info.app.name

=MyService

info.app.description

=My awesome service

info.app.version

=1.0.0

Automatically expand info properties at build time

Rather than hardcoding some properties that are also specified in your project’s build configuration, you can automatically expand info properties using the existing build configuration instead. This is possible in both Maven and Gradle.

Automatic property expansion using Maven

You can automatically expand info properties from the Maven project using resource filtering. If you use the spring-boot-starter-parent

you can then refer to your Maven ‘project properties’ via

@[email protected] placeholders, e.g.

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project.artifactId

=myproject

project.name

=Demo

project.version

=X.X.X.X

project.description

=Demo project for info endpoint

info.build.artifact

[email protected]@

info.build.name

[email protected]@

info.build.description

[email protected]@

info.build.version

[email protected]@

Tip

The spring-boot:run

can add src/main/resources

directly to the classpath (for hot reloading purposes) if you enable the addResources

flag. This circumvents the resource filtering and this feature. You can use the exec:java

goal instead or customize the plugin’s configuration, see the plugin usage page for more details.

If you don’t use the starter parent, in your pom.xml

you need (inside the

<build/>

element):

<resources>

<resource>

<directory>

src/main/resources

</directory>

<filtering>

true

</filtering>

</resource>

</resources>

and (inside

<plugins/>

):

<plugin>

<groupId>

org.apache.maven.plugins

</groupId>

<artifactId>

maven-resources-plugin

</artifactId>

<version>

2.6

</version>

<configuration>

<delimiters>

<delimiter>

@

</delimiter>

</delimiters>

<useDefaultDelimiters>

false

</useDefaultDelimiters>

</configuration>

</plugin>

Note

The useDefaultDelimiters

property is important if you are using standard Spring placeholders in your configuration (e.g.

${foo}

). These may be expanded by the build if that property is not set to false

.

Automatic property expansion using Gradle

You can automatically expand info properties from the Gradle project by configuring the Java plugin’s processResources

task to do so: processResources {

expand(project.properties)

}

You can then refer to your Gradle project’s properties via placeholders, e.g.

info.build.name

=${name}

info.build.description

=${description}

info.build.version

=${version}

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Note

Gradle’s expand

method uses Groovy’s

SimpleTemplateEngine

which transforms

${..} tokens. The

${..}

style conflicts with Spring’s own property placeholder mechanism. To use

Spring property placeholders together with automatic expansion the Spring property placeholders need to be escaped like

\${..}

.

Git commit information

Another useful feature of the info

endpoint is its ability to publish information about the state of your git

source code repository when the project was built. If a git.properties

file is contained in your jar the git.branch

and git.commit

properties will be loaded.

For Maven users the spring-boot-starter-parent

POM includes a pre-configured plugin to generate a git.properties

file. Simply add the following declaration to your POM:

<build>

<plugins>

<plugin>

<groupId>

pl.project13.maven

</groupId>

<artifactId>

git-commit-id-plugin

</artifactId>

</plugin>

</plugins>

</build>

Gradle users can achieve the same result using the gradle-git-properties

plugin plugins {

id

"com.gorylenko.gradle-git-properties"

version

"1.4.6"

}

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46. Monitoring and management over HTTP

If you are developing a Spring MVC application, Spring Boot Actuator will auto-configure all enabled endpoints to be exposed over HTTP. The default convention is to use the id

of the endpoint as the URL path. For example, health

is exposed as

/health

.

46.1 Securing sensitive endpoints

If you add ‘Spring Security’ to your project, all sensitive endpoints exposed over HTTP will be protected.

By default ‘basic’ authentication will be used with the username user

and a generated password (which is printed on the console when the application starts).

Tip

Generated passwords are logged as the application starts. Search for ‘Using default security password’.

You can use Spring properties to change the username and password and to change the security role required to access the endpoints. For example, you might set the following in your application.properties

:

security.user.name

=admin

security.user.password

=secret

management.security.role

=SUPERUSER

Tip

If you don’t use Spring Security and your HTTP endpoints are exposed publicly, you should carefully consider which endpoints you enable. See

Section 45.1, “Customizing endpoints” for

details of how you can set endpoints.enabled

to false

then “opt-in” only specific endpoints.

46.2 Customizing the management endpoint paths

Sometimes it is useful to group all management endpoints under a single path. For example, your application might already use

/info

for another purpose. You can use the management.contextpath

property to set a prefix for your management endpoint:

management.context-path

=/manage

The application.properties

example above will change the endpoint from

/{id}

to

/manage/

{id}

(e.g.

/manage/info

).

You can also change the “id” of an endpoint (using endpoints.{name}.id

) which then changes the default resource path for the MVC endpoint. Legal endpoint ids are composed only of alphanumeric characters (because they can be exposed in a number of places, including JMX object names, where special characters are forbidden). The MVC path can be changed separately by configuring endpoints.{name}.path

, and there is no validation on those values (so you can use anything that is legal in a URL path). For example, to change the location of the

/health

endpoint to

/ping/me

you can set endpoints.health.path=/ping/me

.

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Tip

If you provide a custom

MvcEndpoint

remember to include a settable path

property, and default it to

/{id}

if you want your code to behave like the standard MVC endpoints. (Take a look at the

HealthMvcEndpoint

to see how you might do that.) If your custom endpoint is an

Endpoint

(not an

MvcEndpoint

) then Spring Boot will take care of the path for you.

46.3 Customizing the management server port

Exposing management endpoints using the default HTTP port is a sensible choice for cloud based deployments. If, however, your application runs inside your own data center you may prefer to expose endpoints using a different HTTP port.

The management.port

property can be used to change the HTTP port.

management.port

=8081

Since your management port is often protected by a firewall, and not exposed to the public you might not need security on the management endpoints, even if your main application is secure. In that case you will have Spring Security on the classpath, and you can disable management security like this:

management.security.enabled

=false

(If you don’t have Spring Security on the classpath then there is no need to explicitly disable the management security in this way, and it might even break the application.)

46.4 Customizing the management server address

You can customize the address that the management endpoints are available on by setting the management.address

property. This can be useful if you want to listen only on an internal or opsfacing network, or to only listen for connections from localhost

.

Note

You can only listen on a different address if the port is different to the main server port.

Here is an example application.properties

that will not allow remote management connections:

management.port

=8081

management.address

=127.0.0.1

46.5 Disabling HTTP endpoints

If you don’t want to expose endpoints over HTTP you can set the management port to

-1

:

management.port

=-1

46.6 HTTP health endpoint access restrictions

The information exposed by the health endpoint varies depending on whether or not it’s accessed anonymously, and whether or not the enclosing application is secure. By default, when accessed anonymously in a secure application, any details about the server’s health are hidden and the endpoint will simply indicate whether or not the server is up or down. Furthermore, when accessed anonymously,

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property is used to configure the caching period in milliseconds. It defaults to 1000, i.e. one second.

The above-described restrictions can be enhanced, thereby allowing only authenticated users full access to the health endpoint in a secure application. To do so, set endpoints.health.sensitive

to true

. Here’s a summary of behavior (with default sensitive

flag value “false” indicated in bold): false false true true

false

true

false

true

Full content

Status only

Status only

No content

Authenticated

Full content

Full content

Full content

Full content

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47. Monitoring and management over JMX

Java Management Extensions (JMX) provide a standard mechanism to monitor and manage applications. By default Spring Boot will expose management endpoints as JMX MBeans under the org.springframework.boot

domain.

47.1 Customizing MBean names

The name of the MBean is usually generated from the id

of the endpoint. For example the health endpoint is exposed as org.springframework.boot/Endpoint/healthEndpoint

.

If your application contains more than one Spring

ApplicationContext

you may find that names clash. To solve this problem you can set the endpoints.jmx.unique-names

property to true

so that MBean names are always unique.

You can also customize the JMX domain under which endpoints are exposed. Here is an example application.properties

:

endpoints.jmx.domain

=myapp

endpoints.jmx.unique-names

=true

47.2 Disabling JMX endpoints

If you don’t want to expose endpoints over JMX you can set the endpoints.jmx.enabled

property to false

:

endpoints.jmx.enabled

=false

47.3 Using Jolokia for JMX over HTTP

Jolokia is a JMX-HTTP bridge giving an alternative method of accessing JMX beans. To use Jolokia, simply include a dependency to org.jolokia:jolokia-core

. For example, using Maven you would add the following:

<dependency>

<groupId>

org.jolokia

</groupId>

<artifactId>

jolokia-core

</artifactId>

</dependency>

Jolokia can then be accessed using

/jolokia

on your management HTTP server.

Customizing Jolokia

Jolokia has a number of settings that you would traditionally configure using servlet parameters.

With Spring Boot you can use your application.properties

, simply prefix the parameter with jolokia.config.

:

jolokia.config.debug

=true

Disabling Jolokia

If you are using Jolokia but you don’t want Spring Boot to configure it, simply set the endpoints.jolokia.enabled

property to false

:

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=false

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48. Monitoring and management using a remote shell

Spring Boot supports an integrated Java shell called ‘CRaSH’. You can use CRaSH to ssh

or telnet into your running application. To enable remote shell support, add the following dependency to your project:

<dependency>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter-remote-shell

</artifactId>

</dependency>

Tip

If you want to also enable telnet access you will additionally need a dependency on org.crsh:crsh.shell.telnet

.

Note

CRaSH requires to run with a JDK as it compiles commands on the fly. If a basic help

command fails, you are probably running with a JRE.

48.1 Connecting to the remote shell

By default the remote shell will listen for connections on port

2000

. The default user is user

and the default password will be randomly generated and displayed in the log output. If your application is using

Spring Security, the shell will use

the same configuration

by default. If not, a simple authentication will be applied and you should see a message like this:

Using default password for shell access: ec03e16c-4cf4-49ee-b745-7c8255c1dd7e

Linux and OSX users can use ssh

to connect to the remote shell, Windows users can download and install PuTTY .

$ ssh -p 2000 [email protected] [email protected]'s password:

. ____ _ __ _ _

/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \

( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \

\\/ ___)| |_)| | | | | || (_| | ) ) ) )

' |____| .__|_| |_|_| |_\__, | / / / /

=========|_|==============|___/=/_/_/_/

:: Spring Boot :: (v1.3.1.BUILD-SNAPSHOT) on myhost

Type help

for a list of commands. Spring Boot provides metrics

, beans

, autoconfig

and endpoint commands.

Remote shell credentials

You can use the shell.auth.simple.user.name

and shell.auth.simple.user.password

properties to configure custom connection credentials. It is also possible to use a ‘Spring

Security’

AuthenticationManager

to handle login duties. See the

CrshAutoConfiguration

and

ShellProperties

Javadoc for full details.

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48.2 Extending the remote shell

The remote shell can be extended in a number of interesting ways.

Remote shell commands

You can write additional shell commands using Groovy or Java (see the CRaSH documentation for details). By default Spring Boot will search for commands in the following locations:

• classpath*:/commands/**

• classpath*:/crash/commands/**

Tip

You can change the search path by settings a shell.command-path-patterns

property.

Here is a simple ‘hello’ command that could be loaded from src/main/resources/commands/ hello.groovy

package

commands

import

org.crsh.cli.Command

import

org.crsh.cli.Usage

import

org.crsh.command.InvocationContext

class

hello {

@Usage("Say Hello")

@Command

def main(InvocationContext context) {

return

"Hello"

}

}

Spring Boot adds some additional attributes to

InvocationContext

that you can access from your command:

Attribute Name

spring.boot.version

spring.version

spring.beanfactory

spring.environment

Description

The version of Spring Boot

The version of the core Spring Framework

Access to the Spring

BeanFactory

Access to the Spring

Environment

Remote shell plugins

In addition to new commands, it is also possible to extend other CRaSH shell features. All Spring Beans that extend org.crsh.plugin.CRaSHPlugin

will be automatically registered with the shell.

For more information please refer to the CRaSH reference documentation .

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49. Metrics

Spring Boot Actuator includes a metrics service with ‘gauge’ and ‘counter’ support. A ‘gauge’ records a single value; and a ‘counter’ records a delta (an increment or decrement). Spring Boot Actuator also provides a

PublicMetrics

interface that you can implement to expose metrics that you cannot record via one of those two mechanisms. Look at

SystemPublicMetrics

for an example.

Metrics for all HTTP requests are automatically recorded, so if you hit the metrics

endpoint you should see a response similar to this:

{

"counter.status.200.root"

: 20

,

"counter.status.200.metrics"

: 3

,

"counter.status.200.star-star"

: 5

,

"counter.status.401.root"

: 4

,

"gauge.response.star-star"

: 6

,

"gauge.response.root"

: 2

,

"gauge.response.metrics"

: 3

,

"classes"

: 5808

,

"classes.loaded"

: 5808

,

"classes.unloaded"

: 0

,

"heap"

: 3728384

,

"heap.committed"

: 986624

,

"heap.init"

: 262144

,

"heap.used"

: 52765

,

"nonheap"

: 0

,

"nonheap.committed"

: 77568

,

"nonheap.init"

: 2496

,

"nonheap.used"

: 75826

,

"mem"

: 986624

,

"mem.free"

: 933858

,

"processors"

: 8

,

"threads"

: 15

,

"threads.daemon"

: 11

,

"threads.peak"

: 15

,

"threads.totalStarted"

: 42

,

"uptime"

: 494836

,

"instance.uptime"

: 489782

,

"datasource.primary.active"

: 5

,

"datasource.primary.usage"

: 0.25

}

Here we can see basic memory

, heap

, class loading

, processor

and thread pool

information along with some HTTP metrics. In this instance the root

(‘/’) and

/metrics

URLs have returned

HTTP

200

responses

20

and

3

times respectively. It also appears that the root

URL returned

HTTP 401

(unauthorized)

4

times. The double asterisks ( star-star

) comes from a request matched by Spring

MVC as

/**

(normally a static resource).

The gauge

shows the last response time for a request. So the last request to root

took

2ms

to respond and the last to

/metrics

took

3ms

.

Note

In this example we are actually accessing the endpoint over HTTP using the

/metrics

URL, this explains why metrics

appears in the response.

49.1 System metrics

The following system metrics are exposed by Spring Boot:

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• The total system memory in KB ( mem

)

• The amount of free memory in KB ( mem.free

)

• The number of processors ( processors

)

• The system uptime in milliseconds ( uptime

)

• The application context uptime in milliseconds ( instance.uptime

)

• The average system load ( systemload.average

)

• Heap information in KB ( heap

, heap.committed

, heap.init

, heap.used

)

• Thread information ( threads

, thread.peak

, thread.daemon

)

• Class load information ( classes

, classes.loaded

, classes.unloaded

)

• Garbage collection information ( gc.xxx.count

, gc.xxx.time

)

49.2 DataSource metrics

The following metrics are exposed for each supported

DataSource

defined in your application:

• The number of active connections ( datasource.xxx.active

)

• The current usage of the connection pool ( datasource.xxx.usage

).

All data source metrics share the datasource.

prefix. The prefix is further qualified for each data source:

• If the data source is the primary data source (that is either the only available data source or the one flagged

@Primary

amongst the existing ones), the prefix is datasource.primary

.

• If the data source bean name ends with

DataSource

, the prefix is the name of the bean without

DataSource

(i.e. datasource.batch

for batchDataSource

).

• In all other cases, the name of the bean is used.

It is possible to override part or all of those defaults by registering a bean with a customized version of

DataSourcePublicMetrics

. By default, Spring Boot provides metadata for all supported data sources; you can add additional

DataSourcePoolMetadataProvider

beans if your favorite data source isn’t supported out of the box. See

DataSourcePoolMetadataProvidersConfiguration for examples.

49.3 Cache metrics

The following metrics are exposed for each supported cache defined in your application:

• The current size of the cache ( cache.xxx.size

)

• Hit ratio ( cache.xxx.hit.ratio

)

• Miss ratio ( cache.xxx.miss.ratio

)

Note

Cache providers do not expose the hit/miss ratio in a consistent way. While some expose an

aggregated value (i.e. the hit ratio since the last time the stats were cleared), others expose a

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temporal value (i.e. the hit ratio of the last second). Check your caching provider documentation for more details.

If two different cache managers happen to define the same cache, the name of the cache is prefixed by the name of the

CacheManager

bean.

It is possible to override part or all of those defaults by registering a bean with a customized version of

CachePublicMetrics

. By default, Spring Boot provides cache statistics for EhCache, Hazelcast,

Infinispan, JCache and Guava. You can add additional

CacheStatisticsProvider

beans if your favorite caching library isn’t supported out of the box. See

CacheStatisticsAutoConfiguration for examples.

49.4 Tomcat session metrics

If you are using Tomcat as your embedded servlet container, session metrics will automatically be exposed. The httpsessions.active

and httpsessions.max

keys provide the number of active and maximum sessions.

49.5 Recording your own metrics

To record your own metrics inject a

CounterService

and/or

GaugeService

into your bean.

The

CounterService

exposes increment

, decrement

and reset

methods; the

GaugeService provides a submit

method.

Here is a simple example that counts the number of times that a method is invoked:

import

org.springframework.beans.factory.annotation.Autowired;

import

org.springframework.boot.actuate.metrics.CounterService;

import

org.springframework.stereotype.Service;

@Service

public class

MyService {

private final

CounterService counterService;

@Autowired

public

MyService(CounterService counterService) {

this

.counterService = counterService;

}

public void

exampleMethod() {

this

.counterService.increment(

"services.system.myservice.invoked"

);

}

}

Tip

You can use any string as a metric name but you should follow guidelines of your chosen store/ graphing technology. Some good guidelines for Graphite are available on Matt Aimonetti’s Blog .

49.6 Adding your own public metrics

To add additional metrics that are computed every time the metrics endpoint is invoked, simply register additional

PublicMetrics

implementation bean(s). By default, all such beans are gathered by the endpoint. You can easily change that by defining your own

MetricsEndpoint

.

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49.7 Special features with Java 8

The default implementation of

GaugeService

and

CounterService

provided by Spring Boot depends on the version of Java that you are using. With Java 8 (or better) the implementation switches to a high-performance version optimized for fast writes, backed by atomic in-memory buffers, rather than by the immutable but relatively expensive

Metric<?>

type (counters are approximately 5 times faster and gauges approximately twice as fast as the repository-based implementations). The Dropwizard metrics services (see below) are also very efficient even for Java 7 (they have backports of some of the

Java 8 concurrency libraries), but they do not record timestamps for metric values. If performance of metric gathering is a concern then it is always advisable to use one of the high-performance options, and also to only read metrics infrequently, so that the writes are buffered locally and only read when needed.

Note

The old

MetricRepository

and its

InMemoryMetricRepository

implementation are not used by default if you are on Java 8 or if you are using Dropwizard metrics.

49.8 Metric writers, exporters and aggregation

Spring Boot provides a couple of implementations of a marker interface called

Exporter

which can be used to copy metric readings from the in-memory buffers to a place where they can be analyzed and displayed. Indeed, if you provide a

@Bean

that implements the

MetricWriter interface (or

GaugeWriter

for simple use cases) and mark it

@ExportMetricWriter

, then it will automatically be hooked up to an

Exporter

and fed metric updates every 5 seconds (configured via spring.metrics.export.delay-millis

). In addition, any

MetricReader

that you define and mark as

@ExportMetricReader

will have its values exported by the default exporter.

The default exporter is a

MetricCopyExporter

which tries to optimize itself by not copying values that haven’t changed since it was last called (the optimization can be switched off using a flag spring.metrics.export.send-latest

). Note also that the Dropwizard

MetricRegistry

has no support for timestamps, so the optimization is not available if you are using Dropwizard metrics (all metrics will be copied on every tick).

The default values for the export trigger ( delay-millis

, includes

, excludes

and send-latest

) can be set as spring.metrics.export.*

. Individual values for specific

MetricWriters

can be set as spring.metrics.export.triggers.<name>.*

where

<name>

is a bean name (or pattern for matching bean names).

Warning

The automatic export of metrics is disabled if you switch off the default

MetricRepository

(e.g.

by using Dropwizard metrics). You can get back the same functionality be declaring a bean of your own of type

MetricReader

and declaring it to be

@ExportMetricReader

.

Example: Export to Redis

If you provide a

@Bean

of type

RedisMetricRepository

and mark it

@ExportMetricWriter the metrics are exported to a Redis cache for aggregation. The

RedisMetricRepository

has two important parameters to configure it for this purpose: prefix

and key

(passed into its constructor).

It is best to use a prefix that is unique to the application instance (e.g. using a random value and maybe the logical name of the application to make it possible to correlate with other instances of the

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“globally”, whatever that means for your system (e.g. two instances of the same system could share a

Redis cache if they have distinct keys).

Example:

@Bean

@ExportMetricWriter

MetricWriter metricWriter(MetricExportProperties export) {

return new

RedisMetricRepository(connectionFactory,

export.getRedis().getPrefix(), export.getRedis().getKey());

}

application.properties. spring.metrics.export.redis.prefix

: metrics.mysystem.${spring.application.name:application}.

${random.value:0000}

spring.metrics.export.redis.key

: keys.metrics.mysystem

The prefix is constructed with the application name and id at the end, so it can easily be used to identify a group of processes with the same logical name later.

Note

It’s important to set both the key

and the prefix

. The key is used for all repository operations, and can be shared by multiple repositories. If multiple repositories share a key (like in the case where you need to aggregate across them), then you normally have a read-only “master” repository that has a short, but identifiable, prefix (like “metrics.mysystem”), and many write-only repositories with prefixes that start with the master prefix (like metrics.mysystem.*

in the example above).

It is efficient to read all the keys from a “master” repository like that, but inefficient to read a subset with a longer prefix (e.g. using one of the writing repositories).

Tip

The example above uses

MetricExportProperties

to inject and extract the key and prefix.

This is provided to you as a convenience by Spring Boot, configured with sensible defaults. There is nothing to stop you using your own values as long as they follow the recommendations.

Example: Export to Open TSDB

If you provide a

@Bean

of type

OpenTsdbGaugeWriter

and mark it

@ExportMetricWriter

metrics are exported to Open TSDB for aggregation. The

OpenTsdbGaugeWriter

has a url

property that you need to set to the Open TSDB “/put” endpoint, e.g. localhost:4242/api/put

). It also has a namingStrategy

that you can customize or configure to make the metrics match the data structure you need on the server. By default it just passes through the metric name as an Open TSDB metric name, and adds the tags “domain” (with value “org.springframework.metrics”) and “process” (with the value equal to the object hash of the naming strategy). Thus, after running the application and generating some metrics you can inspect the metrics in the TSD UI ( localhost:4242 by default).

Example: curl localhost:4242/api/query?start=1h-ago&m=max:counter.status.200.root

[

{

"metric": "counter.status.200.root",

"tags": {

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"domain": "org.springframework.metrics",

"process": "b968a76"

},

"aggregateTags": [],

"dps": {

"1430492872": 2,

"1430492875": 6

}

}

]

Example: Export to Statsd

To export metrics to Statsd, make sure first that you have added com.timgroup:java-statsdclient

as a dependency of your project (Spring Boot provides a dependency management for it).

Then add a spring.metrics.export.statsd.host

value to your application.properties

file. Connections will be opened to port

8125

unless a spring.metrics.export.statsd.port

override is provided. You can use spring.metrics.export.statsd.prefix

if you want a custom prefix.

Alternatively, you can provide a

@Bean

of type

StatsdMetricWriter

and mark it

@ExportMetricWriter

:

@Value("${spring.application.name:application}.${random.value:0000}")

private

String prefix =

"metrics"

;

@Bean

@ExportMetricWriter

MetricWriter metricWriter() {

return new

StatsdMetricWriter(prefix,

"localhost"

,

"8125"

);

}

Example: Export to JMX

If you provide a

@Bean

of type

JmxMetricWriter

marked

@ExportMetricWriter

the metrics are exported as MBeans to the local server (the

MBeanExporter

is provided by Spring Boot JMX autoconfiguration as long as it is switched on). Metrics can then be inspected, graphed, alerted etc. using any tool that understands JMX (e.g. JConsole or JVisualVM).

Example:

@Bean

@ExportMetricWriter

MetricWriter metricWriter(MBeanExporter exporter) {

return new

JmxMetricWriter(exporter);

}

Each metric is exported as an individual MBean. The format for the

ObjectNames

is given by an

ObjectNamingStrategy

which can be injected into the

JmxMetricWriter

(the default breaks up the metric name and tags the first two period-separated sections in a way that should make the metrics group nicely in JVisualVM or JConsole).

49.9 Aggregating metrics from multiple sources

There is an

AggregateMetricReader

that you can use to consolidate metrics from different physical sources. Sources for the same logical metric just need to publish them with a period-separated prefix, and the reader will aggregate (by truncating the metric names, and dropping the prefix). Counters are summed and everything else (i.e. gauges) take their most recent value.

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This is very useful if multiple application instances are feeding to a central (e.g. Redis) repository and you want to display the results. Particularly recommended in conjunction with a

MetricReaderPublicMetrics

for hooking up to the results to the “/metrics” endpoint.

Example:

@Autowired

private

MetricExportProperties export;

@Bean

public

PublicMetrics metricsAggregate() {

return new

MetricReaderPublicMetrics(aggregatesMetricReader());

}

private

MetricReader globalMetricsForAggregation() {

return new

RedisMetricRepository(

this

.connectionFactory,

this

.export.getRedis().getAggregatePrefix(),

this

.export.getRedis().getKey());

}

private

MetricReader aggregatesMetricReader() {

AggregateMetricReader repository =

new

AggregateMetricReader(

globalMetricsForAggregation());

return

repository;

}

Note

The example above uses

MetricExportProperties

to inject and extract the key and prefix.

This is provided to you as a convenience by Spring Boot, and the defaults will be sensible. They are set up in

MetricExportAutoConfiguration

.

Note

The

MetricReaders

above are not

@Beans

and are not marked as

@ExportMetricReader because they are just collecting and analyzing data from other repositories, and don’t want to export their values.

49.10 Dropwizard Metrics

A default

MetricRegistry

Spring bean will be created when you declare a dependency to the io.dropwizard.metrics:metrics-core

library; you can also register you own

@Bean

instance if you need customizations. Users of the Dropwizard ‘Metrics’ library will find that Spring Boot metrics are automatically published to com.codahale.metrics.MetricRegistry

. Metrics from the

MetricRegistry

are also automatically exposed via the

/metrics

endpoint

When Dropwizard metrics are in use, the default

CounterService

and

GaugeService

are replaced with a

DropwizardMetricServices

, which is a wrapper around the

MetricRegistry

(so you can

@Autowired

one of those services and use it as normal). You can also create “special” Dropwizard metrics by prefixing your metric names with the appropriate type (i.e. timer.*

, histogram.*

for gauges, and meter.*

for counters).

49.11 Message channel integration

If a

MessageChannel

bean called metricsChannel

exists, then a

MetricWriter

will be created that writes metrics to that channel. The writer is automatically hooked up to an exporter (as for all writers), so all metric values will appear on the channel, and additional analysis or actions can be taken by subscribers (it’s up to you to provide the channel and any subscribers you need).

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50. Auditing

Spring Boot Actuator has a flexible audit framework that will publish events once Spring Security is in play (‘authentication success’, ‘failure’ and ‘access denied’ exceptions by default). This can be very useful for reporting, and also to implement a lock-out policy based on authentication failures. To customize published security events you can provide your own implementations of

AbstractAuthenticationAuditListener

and

AbstractAuthorizationAuditListener

.

You can also choose to use the audit services for your own business events. To do that you can either inject the existing

AuditEventRepository

into your own components and use that directly, or you can simply publish

AuditApplicationEvent

via the Spring

ApplicationEventPublisher

(using

ApplicationEventPublisherAware

).

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51. Tracing

Tracing is automatically enabled for all HTTP requests. You can view the trace

endpoint and obtain basic information about the last few requests:

[

{

"timestamp"

: 1394343677415

,

"info"

:

{

"method"

:

"GET"

,

"path"

:

"/trace"

,

"headers"

:

{

"request"

:

{

"Accept"

:

"text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"

,

"Connection"

:

"keep-alive"

,

"Accept-Encoding"

:

"gzip, deflate"

,

"User-Agent"

:

"Mozilla/5.0 Gecko/Firefox"

,

"Accept-Language"

:

"en-US,en;q=0.5"

,

"Cookie"

:

"_ga=GA1.1.827067509.1390890128; ..."

"Authorization"

:

"Basic ..."

,

"Host"

:

"localhost:8080"

},

"response"

:

{

"Strict-Transport-Security"

:

"max-age=31536000 ; includeSubDomains"

,

"X-Application-Context"

:

"application:8080"

,

"Content-Type"

:

"application/json;charset=UTF-8"

,

"status"

:

"200"

}

}

}

},

{

"timestamp"

: 1394343684465

,

...

}]

51.1 Custom tracing

If you need to trace additional events you can inject a

TraceRepository

into your Spring beans. The add

method accepts a single

Map

structure that will be converted to JSON and logged.

By default an

InMemoryTraceRepository

will be used that stores the last 100 events. You can define your own instance of the

InMemoryTraceRepository

bean if you need to expand the capacity. You can also create your own alternative

TraceRepository

implementation if needed.

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52. Process monitoring

In Spring Boot Actuator you can find a couple of classes to create files that are useful for process monitoring:

ApplicationPidFileWriter

creates a file containing the application PID (by default in the application directory with the file name application.pid

).

EmbeddedServerPortFileWriter

creates a file (or files) containing the ports of the embedded server (by default in the application directory with the file name application.port

).

These writers are not activated by default, but you can enable them in one of the ways described below.

52.1 Extend configuration

In

META-INF/spring.factories

file you can activate the listener(s) that writes a PID file. Example: org.springframework.context.ApplicationListener=\ org.springframework.boot.actuate.system.ApplicationPidFileWriter, org.springframework.boot.actuate.system.EmbeddedServerPortFileWriter

52.2 Programmatically

You can also activate a listener by invoking the

SpringApplication.addListeners(…)

method and passing the appropriate

Writer

object. This method also allows you to customize the file name and path via the

Writer

constructor.

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53. What to read next

If you want to explore some of the concepts discussed in this chapter, you can take a look at the actuator sample applications . You also might want to read about graphing tools such as Graphite .

Otherwise, you can continue on, to read about

‘deployment options’ or jump ahead for some in-depth

information about Spring Boot’s

build tool plugins

.

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Part VI. Deploying

Spring Boot applications

Spring Boot’s flexible packaging options provide a great deal of choice when it comes to deploying your application. You can easily deploy Spring Boot applications to a variety of cloud platforms, to a container images (such as Docker) or to virtual/real machines.

This section covers some of the more common deployment scenarios.

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54. Deploying to the cloud

Spring Boot’s executable jars are ready-made for most popular cloud PaaS (platform-as-a-service) providers. These providers tend to require that you “bring your own container”; they manage application processes (not Java applications specifically), so they need some intermediary layer that adapts your application to the cloud’s notion of a running process.

Two popular cloud providers, Heroku and Cloud Foundry, employ a “buildpack” approach. The buildpack wraps your deployed code in whatever is needed to start your application: it might be a JDK and a call to java

, it might be an embedded web server, or it might be a full-fledged application server. A buildpack is pluggable, but ideally you should be able to get by with as few customizations to it as possible. This reduces the footprint of functionality that is not under your control. It minimizes divergence between development and production environments.

Ideally, your application, like a Spring Boot executable jar, has everything that it needs to run packaged within it.

In this section we’ll look at what it takes to get the

simple application that we developed

in the “Getting

Started” section up and running in the Cloud.

54.1 Cloud Foundry

Cloud Foundry provides default buildpacks that come into play if no other buildpack is specified. The

Cloud Foundry Java buildpack has excellent support for Spring applications, including Spring Boot. You can deploy stand-alone executable jar applications, as well as traditional

.war

packaged applications.

Once you’ve built your application (using, for example, mvn clean package

) and installed the cf command line tool , simply deploy your application using the cf push

command as follows, substituting the path to your compiled

.jar

. Be sure to have logged in with your cf

command line client before pushing an application.

$ cf push acloudyspringtime -p target/demo-0.0.1-SNAPSHOT.jar

See the cf push

documentation for more options. If there is a Cloud Foundry manifest.yml

file present in the same directory, it will be consulted.

Note

Here we are substituting acloudyspringtime

for whatever value you give cf

as the name of your application.

At this point cf

will start uploading your application:

Uploading acloudyspringtime... OK

Preparing to start acloudyspringtime... OK

-----> Downloaded app package (8.9M)

-----> Java Buildpack source: system

-----> Downloading Open JDK 1.7.0_51 from .../x86_64/openjdk-1.7.0_51.tar.gz (1.8s)

Expanding Open JDK to .java-buildpack/open_jdk (1.2s)

-----> Downloading Spring Auto Reconfiguration from 0.8.7 .../auto-reconfiguration-0.8.7.jar (0.1s)

-----> Uploading droplet (44M)

Checking status of app 'acloudyspringtime'...

0 of 1 instances running (1 starting)

...

0 of 1 instances running (1 down)

...

0 of 1 instances running (1 starting)

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...

1 of 1 instances running (1 running)

App started

Congratulations! The application is now live!

It’s easy to then verify the status of the deployed application:

$ cf apps

Getting applications in ...

OK name requested state instances memory disk urls

...

acloudyspringtime started 1/1 512M 1G acloudyspringtime.cfapps.io

...

Once Cloud Foundry acknowledges that your application has been deployed, you should be able to hit the application at the URI given, in this case acloudyspringtime.cfapps.io/

.

Binding to services

By default, metadata about the running application as well as service connection information is exposed to the application as environment variables (for example:

$VCAP_SERVICES

). This architecture decision is due to Cloud Foundry’s polyglot (any language and platform can be supported as a buildpack) nature; process-scoped environment variables are language agnostic.

Environment variables don’t always make for the easiest API so Spring Boot automatically extracts them and flattens the data into properties that can be accessed through Spring’s

Environment

abstraction:

@Component

class

MyBean

implements

EnvironmentAware {

private

String instanceId;

@Override

public void

setEnvironment(Environment environment) {

this

.instanceId = environment.getProperty(

"vcap.application.instance_id"

);

}

// ...

}

All Cloud Foundry properties are prefixed with vcap

. You can use vcap properties to access application information (such as the public URL of the application) and service information (such as database credentials). See

VcapApplicationListener

Javadoc for complete details.

Tip

The Spring Cloud Connectors project is a better fit for tasks such as configuring a DataSource.

Spring Boot includes auto-configuration support and a spring-boot-starter-cloudconnectors

starter POM.

54.2 Heroku

Heroku is another popular PaaS platform. To customize Heroku builds, you provide a

Procfile

, which provides the incantation required to deploy an application. Heroku assigns a port

for the Java application to use and then ensures that routing to the external URI works.

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You must configure your application to listen on the correct port. Here’s the

Procfile

for our starter

REST application: web: java -Dserver.port=$PORT -jar target/demo-0.0.1-SNAPSHOT.jar

Spring Boot makes

-D

arguments available as properties accessible from a Spring

Environment instance. The server.port

configuration property is fed to the embedded Tomcat, Jetty or Undertow instance which then uses it when it starts up. The

$PORT

environment variable is assigned to us by the Heroku PaaS.

Heroku by default will use Java 1.8. This is fine as long as your Maven or Gradle build is set to use the same version (Maven users can use the java.version property). If you want to use JDK 1.7, create a new file adjacent to your pom.xml

and

Procfile

, called system.properties

. In this file add the following: java.runtime.version=1.7

This should be everything you need. The most common workflow for Heroku deployments is to git push

the code to production.

$ git push heroku master

Initializing repository, done.

Counting objects: 95, done.

Delta compression using up to 8 threads.

Compressing objects: 100% (78/78), done.

Writing objects: 100% (95/95), 8.66 MiB | 606.00 KiB/s, done.

Total 95 (delta 31), reused 0 (delta 0)

-----> Java app detected

-----> Installing OpenJDK 1.8... done

-----> Installing Maven 3.3.1... done

-----> Installing settings.xml... done

-----> Executing: mvn -B -DskipTests=true clean install

[INFO] Scanning for projects...

Downloading: http://repo.spring.io/...

Downloaded: http://repo.spring.io/... (818 B at 1.8 KB/sec)

....

Downloaded: http://s3pository.heroku.com/jvm/... (152 KB at 595.3 KB/sec)

[INFO] Installing /tmp/build_0c35a5d2-a067-4abc-a232-14b1fb7a8229/target/...

[INFO] Installing /tmp/build_0c35a5d2-a067-4abc-a232-14b1fb7a8229/pom.xml ...

[INFO] ------------------------------------------------------------------------

[INFO] BUILD SUCCESS

[INFO] ------------------------------------------------------------------------

[INFO] Total time: 59.358s

[INFO] Finished at: Fri Mar 07 07:28:25 UTC 2014

[INFO] Final Memory: 20M/493M

[INFO] ------------------------------------------------------------------------

-----> Discovering process types

Procfile declares types -> web

-----> Compressing... done, 70.4MB

-----> Launching... done, v6

http://agile-sierra-1405.herokuapp.com/ deployed to Heroku

To [email protected]ku.com:agile-sierra-1405.git

* [new branch] master -> master

Your application should now be up and running on Heroku.

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54.3 OpenShift

OpenShift is the RedHat public (and enterprise) PaaS solution. Like Heroku, it works by running scripts triggered by git commits, so you can script the launching of a Spring Boot application in pretty much any way you like as long as the Java runtime is available (which is a standard feature you can ask for at

OpenShift). To do this you can use the DIY Cartridge and hooks in your repository under

.openshift/ action_scripts

:

The basic model is to:

1. Ensure Java and your build tool are installed remotely, e.g. using a pre_build

hook (Java and

Maven are installed by default, Gradle is not)

2. Use a build

hook to build your jar (using Maven or Gradle), e.g.

#!/bin/bash cd $OPENSHIFT_REPO_DIR mvn package -s .openshift/settings.xml -DskipTests=true

3. Add a start

hook that calls java -jar …

#!/bin/bash cd $OPENSHIFT_REPO_DIR nohup java -jar target/*.jar --server.port=${OPENSHIFT_DIY_PORT} --server.address=${OPENSHIFT_DIY_IP}

&

4. Use a stop

hook (since the start is supposed to return cleanly), e.g.

#!/bin/bash source $OPENSHIFT_CARTRIDGE_SDK_BASH

PID=$(ps -ef | grep java.*\.jar | grep -v grep | awk '{ print $2 }') if [ -z "$PID" ] then

client_result "Application is already stopped" else

kill $PID fi

5. Embed service bindings from environment variables provided by the platform in your application.properties

, e.g.

spring.datasource.url: jdbc:mysql://${OPENSHIFT_MYSQL_DB_HOST}:${OPENSHIFT_MYSQL_DB_PORT}/

${OPENSHIFT_APP_NAME} spring.datasource.username: ${OPENSHIFT_MYSQL_DB_USERNAME} spring.datasource.password: ${OPENSHIFT_MYSQL_DB_PASSWORD}

There’s a blog on running Gradle in OpenShift on their website that will get you started with a gradle build to run the app.

54.4 Boxfuse and Amazon Web Services

Boxfuse works by turning your Spring Boot executable jar or war into a minimal VM image that can be deployed unchanged either on VirtualBox or on AWS. Boxfuse comes with deep integration for Spring

Boot and will use the information from your Spring Boot configuration file to automatically configure ports and health check URLs. Boxfuse leverages this information both for the images it produces as well as for all the resources it provisions (instances, security groups, elastic load balancers, etc).

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Once you have created a Boxfuse account , connected it to your AWS account, and installed the latest version of the Boxfuse Client, you can deploy your Spring Boot application to AWS as follows (ensure the application has been built by Maven or Gradle first using, for example, mvn clean package

):

$ boxfuse run myapp-1.0.jar -env=prod

See the boxfuse run

documentation for more options. If there is a boxfuse.com/docs/commandline/

#configuration [ boxfuse.conf

] file present in the current directory, it will be consulted.

Tip

By default Boxfuse will activate a Spring profile named boxfuse

on startup and if your executable jar or war contains an boxfuse.com/docs/payloads/springboot.html#configuration

[ application-boxfuse.properties

] file, Boxfuse will base its configuration based on the properties it contains.

At this point boxfuse

will create an image for your application, upload it, and then configure and start the necessary resources on AWS:

Fusing Image for myapp-1.0.jar ...

Image fused in 00:06.838s (53937 K) -> axelfontaine/myapp:1.0

Creating axelfontaine/myapp ...

Pushing axelfontaine/myapp:1.0 ...

Verifying axelfontaine/myapp:1.0 ...

Creating Elastic IP ...

Mapping myapp-axelfontaine.boxfuse.io to 52.28.233.167 ...

Waiting for AWS to create an AMI for axelfontaine/myapp:1.0 in eu-central-1 (this may take up to 50

seconds) ...

AMI created in 00:23.557s -> ami-d23f38cf

Creating security group boxfuse-sg_axelfontaine/myapp:1.0 ...

Launching t2.micro instance of axelfontaine/myapp:1.0 (ami-d23f38cf) in eu-central-1 ...

Instance launched in 00:30.306s -> i-92ef9f53

Waiting for AWS to boot Instance i-92ef9f53 and Payload to start at http://52.28.235.61/ ...

Payload started in 00:29.266s -> http://52.28.235.61/

Remapping Elastic IP 52.28.233.167 to i-92ef9f53 ...

Waiting 15s for AWS to complete Elastic IP Zero Downtime transition ...

Deployment completed successfully. axelfontaine/myapp:1.0 is up and running at http://myappaxelfontaine.boxfuse.io/

Your application should now be up and running on AWS.

There’s a blog on deploying Spring Boot apps on EC2 as well as documentation for the Boxfuse Spring

Boot integration on their website that will get you started with a Maven build to run the app.

54.5 Google App Engine

Google App Engine is tied to the Servlet 2.5 API, so you can’t deploy a Spring Application there without some modifications. See the

Servlet 2.5 section of this guide.

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55. Installing Spring Boot applications

In additional to running Spring Boot applications using java -jar

it is also possible to make fully executable applications for Unix systems (Linux, OSX, FreeBSD etc). This makes it very easy to install and manage Spring Boot applications in common production environments. As long as you are generating ‘fully executable’ jars from your build, and you are not using a custom embeddedLaunchScript

, the following techniques can be used.

To create a ‘fully executable’ jar with Maven use the following plugin configuration:

<plugin>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-maven-plugin

</artifactId>

<configuration>

<executable>

true

</executable>

</configuration>

</plugin>

With Gradle, the equivalent configuration would be: apply plugin:

'spring-boot'

springBoot {

executable = true

}

Note

Fully executable jars work by embedding an extra script at the front of the file. Not all tools currently accept this format so you may not always be able to use this technique.

55.1 Unix/Linux services

Spring Boot application can be easily started as Unix/Linux services using either init.d

or systemd

.

Installation as an init.d service (System V)

The default executable script that can be embedded into Spring Boot jars will act as an init.d

script when it is symlinked to

/etc/init.d

. The standard start

, stop

, restart

and status

commands can be used. The script supports the following features:

• Starts the services as the user that owns the jar file

• Tracks application PIDs using

/var/run/<appname>/<appname>.pid

• Writes console logs to

/var/log/<appname>.log

Assuming that you have a Spring Boot application installed in

/var/myapp

, to install a Spring Boot application as an init.d

service simply create a symlink:

$ sudo ln -s /var/myapp/myapp.jar /etc/init.d/myapp

Tip

It is advisable to create a specific user account to run you application. Ensure that you have set the owner of the jar file using chown

before installing your service.

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Once installed, you can start and stop the service in the usual way. You can also flag the application to start automatically using your standard operating system tools. For example, if you use Debian:

$ update-rc.d myapp defaults <priority>

Installation as a systemd service

Systemd is the successor to init.d

scripts, and now being used by many many modern Linux distributions. Although you can continue to use init.d

script with systemd

, it is also possible to launch

Spring Boot applications using systemd

‘service’ scripts.

For example, to run a Spring Boot application installed in var/myapp

as user myapp

you can add the following script in

/etc/systemd/system/myapp.service

:

[Unit]

Description=myapp

After=syslog.target

[Service]

User=myapp

ExecStart=/var/myapp/myapp.jar

SuccessExitStatus=143

[Install]

WantedBy=multi-user.target

Tip

Remember to change the

Description

and

ExecStart

fields for your application.

Customizing the startup script

The script accepts the following parameters as environment variables, so you can change the default behavior in a script or on the command line:

Variable

MODE

Description

The “mode” of operation. The default depends on the way the jar was built, but will usually be auto

(meaning it tries to guess if it is an init script by checking if it is a

symlink in a directory called init.d

). You can explicitly set it to service

so that the stop|start|status|restart

commands work, or to run

if you just want to run the script in the foreground.

PID_FOLDER

The root name of the pid folder (

/var/run

by default).

LOG_FOLDER

The name of the folder to put log files in (

/var/log

by default).

LOG_FILENAME LOG_FOLDER

(

<appname>.log

by default).

APP_NAME

The name of the app. If the jar is run from a symlink the script guesses the app name, but if it is not a symlink, or you want to explicitly set the app name this can be useful.

RUN_ARGS

The arguments to pass to the program (the Spring Boot app).

JAVA_HOME

The location of the java

executable is discovered by using the

PATH

by default, but you can set it explicitly if there is an executable file at

$JAVA_HOME/bin/java

.

JAVA_OPTS

Options that are passed to the JVM when it is launched.

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Variable

JARFILE

DEBUG

Description

The explicit location of the jar file, in case the script is being used to launch a jar that it is not actually embedded in.

if not empty will set the

-x

flag on the shell process, making it easy to see the logic in the script.

Note

The

PID_FOLDER

,

LOG_FOLDER

and

LOG_FILENAME

variables are only valid for an init.d

service. With systemd

the equivalent customizations are made using ‘service’ script. Check the service unit configuration man page for more details.

In addition, the following properties can be changed when the script is written by using the embeddedLaunchScriptProperties

option of the Spring Boot Maven or Gradle plugins.

Name Description

mode

The script mode. Defaults to auto

.

initInfoProvides

section of “INIT INFO”. Defaults to spring-boot-application

for

Gradle and to

${project.artifactId}

for Maven.

initInfoShortDescription

section of “INIT INFO”. Defaults to

Spring Boot

Application

for Gradle and to

${project.name}

for Maven.

initInfoDescription

section of “INIT INFO”. Defaults to

Spring Boot

Application

for Gradle and to

${project.description}

(falling back to

${project.name}

) for Maven.

initInfoChkconfig

section of “INIT INFO”. Defaults to

2345 99 01

.

Defaults to true

.

Customizing the startup script with a conf file

With the exception of

JARFILE

and

APP_NAME

, the above settings can be configured using a

.conf

file,

JAVA_OPTS=-Xmx1024M

LOG_FOLDER=/custom/log/folder

The file should be situated next to the jar file and have the same name but suffixed with

.conf

rather than

.jar

. For example, a jar named

/var/myapp/myapp.jar

will use the configuration file named

/var/myapp/myapp.conf

if it exists.

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56. Microsoft Windows services

Spring Boot application can be started as Windows service using winsw

.

A sample maintained separately to the core of Spring Boot describes step by step how you can create a Windows service for your Spring Boot application.

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57. What to read next

Check out the Cloud Foundry , Heroku , OpenShift and Boxfuse web sites for more information about the kinds of features that a PaaS can offer. These are just four of the most popular Java PaaS providers, since Spring Boot is so amenable to cloud-based deployment you’re free to consider other providers as well.

The next section goes on to cover the

Spring Boot CLI

; or you can jump ahead to read about

build tool plugins

.

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Part VII. Spring Boot CLI

The Spring Boot CLI is a command line tool that can be used if you want to quickly develop with Spring.

It allows you to run Groovy scripts, which means that you have a familiar Java-like syntax, without so much boilerplate code. You can also bootstrap a new project or write your own command for it.

Spring Boot Reference Guide

58. Installing the CLI

The Spring Boot CLI can be installed manually; using SDKMAN! (the SDK Manager) or using Homebrew or MacPorts if you are an OSX user. See

Section 10.2, “Installing the Spring Boot CLI”

in the “Getting started” section for comprehensive installation instructions.

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59. Using the CLI

Once you have installed the CLI you can run it by typing spring

. If you run spring

without any arguments, a simple help screen is displayed:

$ spring usage: spring [--help] [--version]

<command> [<args>]

Available commands are:

run [options] <files> [--] [args]

Run a spring groovy script

... more command help is shown here

You can use help

to get more details about any of the supported commands. For example:

$ spring help run spring run - Run a spring groovy script usage: spring run [options] <files> [--] [args]

Option Description

------ -----------

--autoconfigure [Boolean] Add autoconfigure compiler

transformations (default: true)

--classpath, -cp Additional classpath entries

-e, --edit Open the file with the default system

editor

--no-guess-dependencies Do not attempt to guess dependencies

--no-guess-imports Do not attempt to guess imports

-q, --quiet Quiet logging

-v, --verbose Verbose logging of dependency

resolution

--watch Watch the specified file for changes

The version

command provides a quick way to check which version of Spring Boot you are using.

$ spring version

Spring CLI v1.3.1.BUILD-SNAPSHOT

59.1 Running applications using the CLI

You can compile and run Groovy source code using the run

command. The Spring Boot CLI is completely self-contained so you don’t need any external Groovy installation.

Here is an example “hello world” web application written in Groovy:

hello.groovy.

@RestController

class

WebApplication {

@RequestMapping("/")

String home() {

"Hello World!"

}

}

To compile and run the application type:

$ spring run hello.groovy

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To pass command line arguments to the application, you need to use a

--

to separate them from the

“spring” command arguments, e.g.

$ spring run hello.groovy -- --server.port=9000

To set JVM command line arguments you can use the

JAVA_OPTS

environment variable, e.g.

$ JAVA_OPTS=-Xmx1024m spring run hello.groovy

Deduced “grab” dependencies

Standard Groovy includes a

@Grab

annotation which allows you to declare dependencies on a thirdparty libraries. This useful technique allows Groovy to download jars in the same way as Maven or

Gradle would, but without requiring you to use a build tool.

Spring Boot extends this technique further, and will attempt to deduce which libraries to “grab” based on your code. For example, since the

WebApplication

code above uses

@RestController annotations, “Tomcat” and “Spring MVC” will be grabbed.

The following items are used as “grab hints”:

Items

JdbcTemplate

,

NamedParameterJdbcTemplate

,

DataSource

@EnableJms

@EnableCaching

@Test

@EnableRabbit

@EnableReactor extends

Specification

@EnableBatchProcessing

@MessageEndpoint

@EnableIntegrationPatterns

@EnableDeviceResolver

@Controller @RestController

@EnableWebMvc

@EnableWebSecurity

@EnableTransactionManagement

Grabs

JDBC Application.

JMS Application.

Caching abstraction.

JUnit.

RabbitMQ.

Project Reactor.

Spock test.

Spring Batch.

Spring Integration.

Spring Mobile.

Spring MVC + Embedded Tomcat.

Spring Security.

Spring Transaction Management.

Tip

See subclasses of

CompilerAutoConfiguration

in the Spring Boot CLI source code to understand exactly how customizations are applied.

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Deduced “grab” coordinates

Spring Boot extends Groovy’s standard

@Grab

support by allowing you to specify a dependency without a group or version, for example

@Grab('freemarker')

. This will consult Spring Boot’s default dependency metadata to deduce the artifact’s group and version. Note that the default metadata is tied to the version of the CLI that you’re using – it will only change when you move to a new version of the

CLI, putting you in control of when the versions of your dependencies may change. A table showing the

dependencies and their versions that are included in the default metadata can be found in the appendix .

Default import statements

To help reduce the size of your Groovy code, several import

statements are automatically included.

Notice how the example above refers to

@Component

,

@RestController

and

@RequestMapping without needing to use fully-qualified names or import

statements.

Tip

Many Spring annotations will work without using import

statements. Try running your application to see what fails before adding imports.

Automatic main method

Unlike the equivalent Java application, you do not need to include a public static void main(String[] args)

method with your

Groovy

scripts. A

SpringApplication

is automatically created, with your compiled code acting as the source

.

Custom dependency management

By default, the CLI uses the dependency management declared in spring-boot-dependencies when resolving

@Grab

dependencies. Additional dependency management, that will override the default dependency management, can be configured using the

@DependencyManagementBom

annotation.

The annotation’s value should specify the coordinates ( groupId:artifactId:version

) of one or more Maven BOMs.

For example, the following declaration:

@DependencyManagementBom(

"com.example.custom-bom:1.0.0"

)

Will pick up custom-bom-1.0.0.pom

in a Maven repository under com/example/customversions/1.0.0/

.

When multiple BOMs are specified they are applied in the order that they’re declared. For example:

@DependencyManagementBom([

"com.example.custom-bom:1.0.0"

,

"com.example.another-bom:1.0.0"

]) indicates that dependency management in another-bom

will override the dependency management in custom-bom

.

You can use

@DependencyManagementBom

anywhere that you can use

@Grab

, however, to ensure consistent ordering of the dependency management, you can only use

@DependencyManagementBom at most once in your application. A useful source of dependency management (that is

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@DependencyManagementBom('io.spring.platform:platform-bom:1.1.2.RELEASE')

.

59.2 Testing your code

The test

command allows you to compile and run tests for your application. Typical usage looks like this:

$ spring test app.groovy tests.groovy

Total: 1, Success: 1, : Failures: 0

Passed? true

In this example, tests.groovy

contains JUnit

@Test

methods or Spock

Specification

classes.

All the common framework annotations and static methods should be available to you without having to import

them.

Here is the tests.groovy

file that we used above (with a JUnit test):

class

ApplicationTests {

@Test

void

homeSaysHello() {

assertEquals(

"Hello World!"

,

new

WebApplication().home())

}

}

Tip

If you have more than one test source files, you might prefer to organize them into a test directory.

59.3 Applications with multiple source files

You can use “shell globbing” with all commands that accept file input. This allows you to easily use multiple files from a single directory, e.g.

$ spring run *.groovy

This technique can also be useful if you want to segregate your “test” or “spec” code from the main application code:

$ spring test app/*.groovy test/*.groovy

59.4 Packaging your application

You can use the jar

command to package your application into a self-contained executable jar file.

For example:

$ spring jar my-app.jar *.groovy

The resulting jar will contain the classes produced by compiling the application and all of the application’s dependencies so that it can then be run using java -jar

. The jar file will also contain entries from the application’s classpath. You can add explicit paths to the jar using

--include

and

--exclude

(both are comma-separated, and both accept prefixes to the values “+” and “-” to signify that they should be removed from the defaults). The default includes are

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.*, repository/**, build/**, target/**, **/*.jar, **/*.groovy

See the output of spring help jar

for more information.

59.5 Initialize a new project

The init

command allows you to create a new project using start.spring.io

without leaving the shell.

For example:

$ spring init --dependencies=web,data-jpa my-project

Using service at https://start.spring.io

Project extracted to '/Users/developer/example/my-project'

This creates a my-project

directory with a Maven-based project using spring-boot-starterweb

and spring-boot-starter-data-jpa

. You can list the capabilities of the service using the

-list

flag

$ spring init --list

=======================================

Capabilities of https://start.spring.io

=======================================

Available dependencies:

----------------------actuator - Actuator: Production ready features to help you monitor and manage your application

...

web - Web: Support for full-stack web development, including Tomcat and spring-webmvc websocket - Websocket: Support for WebSocket development ws - WS: Support for Spring Web Services

Available project types:

-----------------------gradle-build - Gradle Config [format:build, build:gradle] gradle-project - Gradle Project [format:project, build:gradle] maven-build - Maven POM [format:build, build:maven] maven-project - Maven Project [format:project, build:maven] (default)

...

The init

command supports many options, check the help

output for more details. For instance, the following command creates a gradle project using Java 8 and war

packaging:

$ spring init --build=gradle --java-version=1.8 --dependencies=websocket --packaging=war sample-app.zip

Using service at https://start.spring.io

Content saved to 'sample-app.zip'

59.6 Using the embedded shell

Spring Boot includes command-line completion scripts for BASH and zsh shells. If you don’t use either of these shells (perhaps you are a Windows user) then you can use the shell

command to launch an integrated shell.

$ spring shell

Spring Boot (v1.3.1.BUILD-SNAPSHOT)

Hit TAB to complete. Type \'help' and hit RETURN for help, and \'exit' to quit.

From inside the embedded shell you can run other commands directly:

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$ version

Spring CLI v1.3.1.BUILD-SNAPSHOT

The embedded shell supports ANSI color output as well as tab

completion. If you need to run a native command you can use the

$

prefix. Hitting ctrl-c

will exit the embedded shell.

59.7 Adding extensions to the CLI

You can add extensions to the CLI using the install

command. The command takes one or more sets of artifact coordinates in the format group:artifact:version

. For example:

$ spring install com.example:spring-boot-cli-extension:1.0.0.RELEASE

In addition to installing the artifacts identified by the coordinates you supply, all of the artifacts' dependencies will also be installed.

To uninstall a dependency use the uninstall

command. As with the install

command, it takes one or more sets of artifact coordinates in the format group:artifact:version

. For example:

$ spring uninstall com.example:spring-boot-cli-extension:1.0.0.RELEASE

It will uninstall the artifacts identified by the coordinates you supply and their dependencies.

To uninstall all additional dependencies you can use the

--all

option. For example:

$ spring uninstall --all

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60. Developing application with the Groovy beans

DSL

Spring Framework 4.0 has native support for a beans{}

“DSL” (borrowed from Grails ), and you can embed bean definitions in your Groovy application scripts using the same format. This is sometimes a good way to include external features like middleware declarations. For example:

@Configuration

class

Application

implements

CommandLineRunner {

@Autowired

SharedService service

@Override

void

run(String... args) {

println service.message

}

}

import

my.company.SharedService

beans {

service(SharedService) {

message =

"Hello World"

}

}

You can mix class declarations with beans{}

in the same file as long as they stay at the top level, or you can put the beans DSL in a separate file if you prefer.

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61. Configuring the CLI with settings.xml

The Spring Boot CLI uses Aether, Maven’s dependency resolution engine, to resolve dependencies.

The CLI makes use of the Maven configuration found in

~/.m2/settings.xml

to configure Aether.

The following configuration settings are honored by the CLI:

• Offline

• Mirrors

• Servers

• Proxies

• Profiles

• Activation

• Repositories

• Active profiles

Please refer to Maven’s settings documentation for further information.

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62. What to read next

There are some sample groovy scripts available from the GitHub repository that you can use to try out the Spring Boot CLI. There is also extensive javadoc throughout the source code .

If you find that you reach the limit of the CLI tool, you will probably want to look at converting your application to full Gradle or Maven built “groovy project”. The next section covers Spring Boot’s

Build tool plugins

that you can use with Gradle or Maven.

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Part VIII. Build tool plugins

Spring Boot provides build tool plugins for Maven and Gradle. The plugins offer a variety of features, including the packaging of executable jars. This section provides more details on both plugins, as well as some help should you need to extend an unsupported build system. If you are just getting started, you might want to read “

Chapter 13, Build systems ” from the

Part III, “Using Spring Boot” section first.

Spring Boot Reference Guide

63. Spring Boot Maven plugin

The Spring Boot Maven Plugin provides Spring Boot support in Maven, allowing you to package executable jar or war archives and run an application “in-place”. To use it you must be using Maven

3.2 (or better).

Note

Refer to the Spring Boot Maven Plugin Site for complete plugin documentation.

63.1 Including the plugin

To use the Spring Boot Maven Plugin simply include the appropriate XML in the plugins

section of your pom.xml

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns

=

"http://maven.apache.org/POM/4.0.0" xmlns:xsi

=

"http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation

=

"http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" >

<modelVersion>

4.0.0

</modelVersion>

<!-- ... -->

<build>

<plugins>

<plugin>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-maven-plugin

</artifactId>

<version>

1.3.1.BUILD-SNAPSHOT

</version>

<executions>

<execution>

<goals>

<goal>

repackage

</goal>

</goals>

</execution>

</executions>

</plugin>

</plugins>

</build>

</project>

This configuration will repackage a jar or war that is built during the package

phase of the Maven lifecycle. The following example shows both the repackaged jar, as well as the original jar, in the target directory:

$ mvn package

$ ls target/*.jar

target/myproject-1.0.0.jar target/myproject-1.0.0.jar.original

If you don’t include the

<execution/>

configuration as above, you can run the plugin on its own (but only if the package goal is used as well). For example:

$ mvn package spring-boot:repackage

$ ls target/*.jar

target/myproject-1.0.0.jar target/myproject-1.0.0.jar.original

If you are using a milestone or snapshot release you will also need to add appropriate pluginRepository

elements:

<pluginRepositories>

<pluginRepository>

<id>

spring-snapshots

</id>

<url>

http://repo.spring.io/snapshot

</url>

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</pluginRepository>

<pluginRepository>

<id>

spring-milestones

</id>

<url>

http://repo.spring.io/milestone

</url>

</pluginRepository>

</pluginRepositories>

63.2 Packaging executable jar and war files

Once spring-boot-maven-plugin

has been included in your pom.xml

it will automatically attempt to rewrite archives to make them executable using the spring-boot:repackage

goal. You should configure your project to build a jar or war (as appropriate) using the usual packaging

element:

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns

=

"http://maven.apache.org/POM/4.0.0" xmlns:xsi

=

"http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation

=

"http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" >

<!-- ... -->

<packaging>

jar

</packaging>

<!-- ... -->

</project>

Your existing archive will be enhanced by Spring Boot during the package

phase. The main class that you want to launch can either be specified using a configuration option, or by adding a

Main-Class attribute to the manifest in the usual way. If you don’t specify a main class the plugin will search for a class with a public static void main(String[] args)

method.

To build and run a project artifact, you can type the following:

$ mvn package

$ java -jar target/mymodule-0.0.1-SNAPSHOT.jar

To build a war file that is both executable and deployable into an external container you need to mark the embedded container dependencies as “provided”, e.g:

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns

=

"http://maven.apache.org/POM/4.0.0" xmlns:xsi

=

"http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation

=

"http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" >

<!-- ... -->

<packaging>

war

</packaging>

<!-- ... -->

<dependencies>

<dependency>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter-web

</artifactId>

</dependency>

<dependency>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter-tomcat

</artifactId>

<scope>

provided

</scope>

</dependency>

<!-- ... -->

</dependencies>

</project>

Tip

See the “ Section 80.1, “Create a deployable war file”

” section for more details on how to create a deployable war file.

Advanced configuration options and examples are available in the plugin info page .

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64. Spring Boot Gradle plugin

The Spring Boot Gradle Plugin provides Spring Boot support in Gradle, allowing you to package executable jar or war archives, run Spring Boot applications and use the dependency management provided by spring-boot-dependencies

.

64.1 Including the plugin

To use the Spring Boot Gradle Plugin simply include a buildscript

dependency and apply the spring-boot

plugin: buildscript {

dependencies {

classpath(

"org.springframework.boot:spring-boot-gradle-plugin:1.3.1.BUILD-SNAPSHOT"

)

}

} apply plugin:

'spring-boot'

If you are using a milestone or snapshot release you will also need to add appropriate repositories reference: buildscript {

repositories {

maven.url

"http://repo.spring.io/snapshot"

maven.url

"http://repo.spring.io/milestone"

}

// ...

}

64.2 Gradle dependency management

The spring-boot

plugin automatically applies the Dependency Management Plugin and configures in to import the spring-boot-starter-parent

bom. This provides a similar dependency management experience to the one that is enjoyed by Maven users. For example, it allows you to omit version numbers when declaring dependencies that are managed in the bom. To make use of this functionality, simply declare dependencies in the usual way, but leave the version number empty: dependencies {

compile(

"org.springframework.boot:spring-boot-starter-web"

)

compile(

"org.thymeleaf:thymeleaf-spring4"

)

compile(

"nz.net.ultraq.thymeleaf:thymeleaf-layout-dialect"

)

}

Note

The version of the spring-boot

gradle plugin that you declare determines the version of the spring-boot-starter-parent

bom that is imported (this ensures that builds are always repeatable). You should always set the version of the spring-boot

gradle plugin to the actual

Spring Boot version that you wish to use. Details of the versions that are provided can be found in the

appendix .

The dependency management plugin will only supply a version where one is not specified. To use a version of an artifact that differs from the one that the plugin would provide, simply specify the version when you declare the dependency as you usually would. For example: dependencies {

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compile(

"org.thymeleaf:thymeleaf-spring4:2.1.1.RELEASE"

)

}

To learn more about the capabilities of the Dependency Management Plugin, please refer to its documentation .

64.3 Packaging executable jar and war files

Once the spring-boot

plugin has been applied to your project it will automatically attempt to rewrite archives to make them executable using the

bootRepackage

task

. You should configure your project to build a jar or war (as appropriate) in the usual way.

The main class that you want to launch can either be specified using a configuration option, or by adding a

Main-Class

attribute to the manifest. If you don’t specify a main class the plugin will search for a class with a public static void main(String[] args)

method.

Tip

Check

Section 64.6, “Repackage configuration”

for a full list of configuration options.

To build and run a project artifact, you can type the following:

$ gradle build

$ java -jar build/libs/mymodule-0.0.1-SNAPSHOT.jar

To build a war file that is both executable and deployable into an external container, you need to mark the embedded container dependencies as belonging to a configuration named “providedRuntime”, e.g:

...

apply plugin:

'war'

war {

baseName =

'myapp'

version =

'0.5.0'

} repositories {

jcenter()

maven { url

"http://repo.spring.io/libs-snapshot"

}

} configurations {

providedRuntime

} dependencies {

compile(

"org.springframework.boot:spring-boot-starter-web"

)

providedRuntime(

"org.springframework.boot:spring-boot-starter-tomcat"

)

...

}

Tip

See the “ Section 80.1, “Create a deployable war file”

” section for more details on how to create a deployable war file.

64.4 Running a project in-place

To run a project in place without building a jar first you can use the “bootRun” task:

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$ gradle bootRun

If

devtools

has been added to your project it will automatically monitor your application for changes.

Alternatively, you can also run the application so that your static classpath resources (i.e. in src/main/ resources

by default) are reloadable in the live application, which can be helpful at development time.

bootRun {

addResources = true

}

Making static classpath resources reloadable means that bootRun

does not use the output of the processResources

task, i.e., when invoked using bootRun

, your application will use the resources in their unprocessed form.

64.5 Spring Boot plugin configuration

The gradle plugin automatically extends your build script DSL with a springBoot

element for global configuration of the Boot plugin. Set the appropriate properties as you would with any other Gradle extension (see below for a list of configuration options): springBoot {

backupSource = false

}

64.6 Repackage configuration

The plugin adds a bootRepackage

task which you can also configure directly, e.g.: bootRepackage {

mainClass =

'demo.Application'

}

The following configuration options are available:

Name

enabled mainClass classifier

Description

Boolean flag to switch the repackager off (sometimes useful if you want the other Boot features but not this one)

The main class that should be run. If not specified, and you have applied the application plugin, the mainClassName

project property will be used. If the application plugin has not been applied or no mainClassName

has been specified, the archive will be searched for a suitable class. "Suitable" means a unique class with a well-formed main()

method (if more than one is found the build will fail). If you have applied the application plugin, the main class can also be specified via its "run" task ( main property) and/or its "startScripts" task ( mainClassName

property) as an alternative to using the "springBoot" configuration.

A file name segment (before the extension) to add to the archive, so that the original is preserved in its original location. Defaults to null in which case the archive is repackaged in place. The default is convenient for many purposes, but if you want to use

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Name

withJarTask customConfiguration executable embeddedLaunchScript

Description

the original jar as a dependency in another project, it’s best to use an extension to define the executable archive.

The name or value of the

Jar

task (defaults to all tasks of type

Jar

) which is used to locate the archive to repackage.

The name of the custom configuration which is used to populate the nested lib directory (without specifying this you get all compile and runtime dependencies).

Boolean flag to indicate if jar files are fully executable on Unix like operating systems. Defaults to false

.

The embedded launch script to prepend to the front of the jar if it is fully executable. If not specified the 'Spring Boot' default script will be used.

excludeDevtools default script supports a mode

property which can contain the values auto

, service

or run

.

Boolean flag to indicate if the devtools jar should be excluded from the repackaged archives. Defaults to false

.

64.7 Repackage with custom Gradle configuration

Sometimes it may be more appropriate to not package default dependencies resolved from compile

, runtime

and provided

scopes. If the created executable jar file is intended to be run as it is, you need to have all dependencies nested inside it; however, if the plan is to explode a jar file and run the main class manually, you may already have some of the libraries available via

CLASSPATH

. This is a situation where you can repackage your jar with a different set of dependencies.

Using a custom configuration will automatically disable dependency resolving from compile

, runtime and provided

scopes. Custom configuration can be either defined globally (inside the springBoot section) or per task.

task clientJar(type: Jar) {

appendix =

'client'

from sourceSets.main.output

exclude(

'**/*Something*'

)

} task clientBoot(type: BootRepackage, dependsOn: clientJar) {

withJarTask = clientJar

customConfiguration =

"mycustomconfiguration"

}

In above example, we created a new clientJar

Jar task to package a customized file set from your compiled sources. Then we created a new clientBoot

BootRepackage task and instructed it to work with only clientJar

task and mycustomconfiguration

.

configurations {

mycustomconfiguration.exclude group:

'log4j'

} dependencies {

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mycustomconfiguration configurations.runtime

}

The configuration that we are referring to in

BootRepackage

is a normal Gradle configuration . In the above example we created a new configuration named mycustomconfiguration

instructing it to derive from a runtime

and exclude the log4j

group. If the clientBoot

task is executed, the repackaged boot jar will have all dependencies from runtime

but no log4j

jars.

Configuration options

The following configuration options are available:

Name

mainClass providedConfiguration backupSource customConfiguration layout requiresUnpack

Description

The main class that should be run by the executable archive.

The name of the provided configuration (defaults to providedRuntime

).

If the original source archive should be backed-up before being repackaged (defaults to true

).

The name of the custom configuration.

The type of archive, corresponding to how the dependencies are laid out inside (defaults to a guess based on the archive type).

A list of dependencies (in the form “groupId:artifactId” that must be unpacked from fat jars in order to run. Items are still packaged into the fat jar, but they will be automatically unpacked when it runs.

64.8 Understanding how the Gradle plugin works

When spring-boot

is applied to your Gradle project a default task named bootRepackage

is created automatically. The bootRepackage

task depends on Gradle assemble

task, and when executed, it tries to find all jar artifacts whose qualifier is empty (i.e. tests and sources jars are automatically skipped).

Due to the fact that bootRepackage

finds 'all' created jar artifacts, the order of Gradle task execution is important. Most projects only create a single jar file, so usually this is not an issue; however, if you are planning to create a more complex project setup, with custom

Jar

and

BootRepackage

tasks, there are few tweaks to consider.

If you are 'just' creating custom jar files from your project you can simply disable default jar

and bootRepackage

tasks: jar.enabled = false bootRepackage.enabled = false

Another option is to instruct the default bootRepackage

task to only work with a default jar

task.

bootRepackage.withJarTask = jar

If you have a default project setup where the main jar file is created and repackaged, 'and' you still want to create additional custom jars, you can combine your custom repackage tasks together and use dependsOn

so that the bootJars

task will run after the default bootRepackage

task is executed:

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All the above tweaks are usually used to avoid situations where an already created boot jar is repackaged again. Repackaging an existing boot jar will not break anything, but you may find that it includes unnecessary dependencies.

64.9 Publishing artifacts to a Maven repository using Gradle

If you are declaring dependencies without versions and you want to publish artifacts to a Maven repository you will need to configure the Maven publication with details of Spring Boot’s dependency management. This can be achieved by configuring it to publish poms that inherit from spring-bootstarter-parent

or that import dependency management from spring-boot-dependencies

. The exact details of this configuration depend on how you’re using Gradle and how you’re trying to publish the artifacts.

Configuring Gradle to produce a pom that inherits dependency management

The following is an example of configuring Gradle to generate a pom that inherits from spring-bootstarter-parent

. Please refer to the Gradle User Guide for further information.

uploadArchives {

repositories {

mavenDeployer {

pom {

project {

parent {

groupId

"org.springframework.boot"

artifactId

"spring-boot-starter-parent"

version

"1.3.1.BUILD-SNAPSHOT"

}

}

}

}

}

}

Configuring Gradle to produce a pom that imports dependency management

The following is an example of configuring Gradle to generate a pom that imports the dependency management provided by spring-boot-dependencies

. Please refer to the Gradle User Guide for further information.

uploadArchives {

repositories {

mavenDeployer {

pom {

project {

dependencyManagement {

dependencies {

dependency {

groupId

"org.springframework.boot"

artifactId

"spring-boot-dependencies"

version

"1.3.1.BUILD-SNAPSHOT"

type

"pom"

scope

"import"

}

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}

}

}

}

}

}

}

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65. Spring Boot AntLib module

The Spring Boot AntLib module provides basic Spring Boot support for Apache Ant. You can use the module to create executable jars. To use the module you need to declare an additional spring-boot namespace in your build.xml

:

<project xmlns:ivy

=

"antlib:org.apache.ivy.ant" xmlns:spring-boot

=

"antlib:org.springframework.boot.ant" name

=

"myapp" default

=

"build" >

...

</project>

You’ll need to remember to start Ant using the

-lib

option, for example:

$ ant -lib <folder containing spring-boot-antlib-1.3.1.BUILD-SNAPSHOT.jar>

Tip

The “Using Spring Boot” section includes a more complete example of

using Apache Ant with spring-boot-antlib

65.1 Spring Boot Ant tasks

Once the spring-boot-antlib

namespace has been declared, the following additional tasks are available.

spring-boot:exejar

The exejar

task can be used to creates a Spring Boot executable jar. The following attributes are supported by the task:

Attribute

destfile classes start-class

Description

The destination jar file to create

The root directory of Java class files

The main application class to run

Required

Yes

Yes

No (default is first class found

declaring a main

method)

The following nested elements can be used with the task:

Element

resources lib

Examples

Specify start-class.

Description

One or more Resource Collections describing a set of Resources that should be added to the content of the created jar file.

One or more Resource Collections that should be added to the set of jar libraries that make up the runtime dependency classpath of the application.

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<spring-boot:exejar destfile

=

"target/my-application.jar" classes

=

"target/classes" start-class

=

"com.foo.MyApplication" >

<resources>

<fileset dir

=

"src/main/resources" />

</resources>

<lib>

<fileset dir

=

"lib" />

</lib>

</spring-boot:exejar>

Detect start-class.

<exejar destfile

=

"target/my-application.jar" classes

=

"target/classes" >

<lib>

<fileset dir

=

"lib" />

</lib>

</exejar>

65.2 spring-boot:findmainclass

The findmainclass

task is used internally by exejar

to locate a class declaring a main

. You can also use this task directly in your build if needed. The following attributes are supported

Attribute

classesroot mainclass property

Description

The root directory of Java class files

Can be used to short-circuit the main class search

The Ant property that should be set with the result

Required

Yes (unless

mainclass

is specified)

No

No (result will be logged if unspecified)

Examples

Find and log.

<findmainclass classesroot

=

"target/classes" />

Find and set.

<findmainclass classesroot

=

"target/classes" property

=

"main-class" />

Override and set.

<findmainclass mainclass

=

"com.foo.MainClass" property

=

"main-class" />

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66. Supporting other build systems

If you want to use a build tool other than Maven, Gradle or Ant, you will likely need to develop your own plugin. Executable jars need to follow a specific format and certain entries need to be written in an

uncompressed form (see the

executable jar format

section in the appendix for details).

The Spring Boot Maven and Gradle plugins both make use of spring-boot-loader-tools

to actually generate jars. You are also free to use this library directly yourself if you need to.

66.1 Repackaging archives

To repackage an existing archive so that it becomes a self-contained executable archive use org.springframework.boot.loader.tools.Repackager

. The

Repackager

class takes a single constructor argument that refers to an existing jar or war archive. Use one of the two available repackage()

methods to either replace the original file or write to a new destination. Various settings can also be configured on the repackager before it is run.

66.2 Nested libraries

When repackaging an archive you can include references to dependency files using the org.springframework.boot.loader.tools.Libraries

interface. We don’t provide any concrete implementations of

Libraries

here as they are usually build system specific.

If your archive already includes libraries you can use

Libraries.NONE

.

66.3 Finding a main class

If you don’t use

Repackager.setMainClass()

to specify a main class, the repackager will use ASM to read class files and attempt to find a suitable class with a public static void main(String[] args)

method. An exception is thrown if more than one candidate is found.

66.4 Example repackage implementation

Here is a typical example repackage:

Repackager repackager =

new

Repackager(sourceJarFile); repackager.setBackupSource(false); repackager.repackage(

new

Libraries() {

@Override

public void

doWithLibraries(LibraryCallback callback)

throws

IOException {

// Build system specific implementation, callback for each dependency

// callback.library(new Library(nestedFile, LibraryScope.COMPILE));

}

});

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67. What to read next

If you’re interested in how the build tool plugins work you can look at the spring-boot-tools

module on GitHub. More technical details of the

executable jar format are covered in the appendix.

If you have specific build-related questions you can check out the “

how-to ” guides.

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This section provides answers to some common ‘how do I do that…’ type of questions that often arise when using Spring Boot. This is by no means an exhaustive list, but it does cover quite a lot.

If you are having a specific problem that we don’t cover here, you might want to check out stackoverflow.com

to see if someone has already provided an answer; this is also a great place to ask new questions (please use the spring-boot

tag).

We’re also more than happy to extend this section; If you want to add a ‘how-to’ you can send us a pull request .

Spring Boot Reference Guide

68. Spring Boot application

68.1 Troubleshoot auto-configuration

The Spring Boot auto-configuration tries its best to ‘do the right thing’, but sometimes things fail and it can be hard to tell why.

There is a really useful

ConditionEvaluationReport

available in any Spring Boot

ApplicationContext

. You will see it if you enable

DEBUG

logging output. If you use the springboot-actuator

there is also an autoconfig

endpoint that renders the report in JSON. Use that to debug the application and see what features have been added (and which not) by Spring Boot at runtime.

Many more questions can be answered by looking at the source code and the javadoc. Some rules of thumb:

• Look for classes called

*AutoConfiguration

and read their sources, in particular the

@Conditional*

annotations to find out what features they enable and when. Add

--debug

to the command line or a System property

-Ddebug

to get a log on the console of all the auto-configuration decisions that were made in your app. In a running Actuator app look at the autoconfig

endpoint

(‘/autoconfig’ or the JMX equivalent) for the same information.

• Look for classes that are

@ConfigurationProperties

(e.g.

ServerProperties

) and read from there the available external configuration options. The

@ConfigurationProperties

has a name

attribute which acts as a prefix to external properties, thus

ServerProperties

has prefix="server"

and its configuration properties are server.port

, server.address

etc. In a running Actuator app look at the configprops

endpoint.

• Look for use of

RelaxedPropertyResolver

to pull configuration values explicitly out of the

Environment

. It often is used with a prefix.

• Look for

@Value

annotations that bind directly to the

Environment

. This is less flexible than the

RelaxedPropertyResolver

approach, but does allow some relaxed binding, specifically for OS environment variables (so

CAPITALS_AND_UNDERSCORES

are synonyms for period.separated

).

• Look for

@ConditionalOnExpression

annotations that switch features on and off in response to

SpEL expressions, normally evaluated with placeholders resolved from the

Environment

.

68.2 Customize the Environment or ApplicationContext before it starts

A

SpringApplication

has

ApplicationListeners

and

ApplicationContextInitializers that are used to apply customizations to the context or environment. Spring Boot loads a number of such customizations for use internally from

META-INF/spring.factories

. There is more than one way to register additional ones:

• Programmatically per application by calling the addListeners

and addInitializers

methods on

SpringApplication

before you run it.

• Declaratively per application by setting context.initializer.classes

or context.listener.classes

.

• Declaratively for all applications by adding a

META-INF/spring.factories

and packaging a jar file that the applications all use as a library.

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The

SpringApplication

sends some special

ApplicationEvents

to the listeners (even some before the context is created), and then registers the listeners for events published by the

ApplicationContext

as well. See

Section 23.4, “Application events and listeners”

in the ‘Spring Boot features’ section for a complete list.

68.3 Build an ApplicationContext hierarchy (adding a parent or root context)

You can use the

ApplicationBuilder

class to create parent/child

ApplicationContext hierarchies. See

Section 23.3, “Fluent builder API”

in the ‘Spring Boot features’ section for more information.

68.4 Create a non-web application

Not all Spring applications have to be web applications (or web services). If you want to execute some code in a main

method, but also bootstrap a Spring application to set up the infrastructure to use, then it’s easy with the

SpringApplication

features of Spring Boot. A

SpringApplication changes its

ApplicationContext

class depending on whether it thinks it needs a web application or not. The first thing you can do to help it is to just leave the servlet API dependencies off the classpath. If you can’t do that (e.g. you are running 2 applications from the same code base) then you can explicitly call setWebEnvironment(false)

on your

SpringApplication

instance, or set the applicationContextClass

property (through the Java API or with external properties). Application code that you want to run as your business logic can be implemented as a

CommandLineRunner

and dropped into the context as a

@Bean

definition.

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69. Properties & configuration

69.1 Externalize the configuration of SpringApplication

A

SpringApplication

has bean properties (mainly setters) so you can use its Java API as you create the application to modify its behavior. Or you can externalize the configuration using properties in spring.main.*

. E.g. in application.properties

you might have.

spring.main.web_environment

=false

spring.main.banner_mode

=off and then the Spring Boot banner will not be printed on startup, and the application will not be a web application.

Note

The example above also demonstrates how flexible binding allows the use of underscores (

_

) as well as dashes (

-

) in property names.

Properties defined in external configuration overrides the values specified via the Java API with the notable exception of the sources used to create the

ApplicationContext

. Let’s consider this application

new

SpringApplicationBuilder()

.bannerMode(Banner.Mode.OFF)

.sources(demo.MyApp.

class

)

.run(args); used with the following configuration:

spring.main.sources

=com.acme.Config,com.acme.ExtraConfig

spring.main.banner_mode

=console

The actual application will now show the banner (as overridden by configuration) and use three sources for the

ApplicationContext

(in that order): demo.MyApp

, com.acme.Config

, com.acme.ExtraConfig

.

69.2 Change the location of external properties of an application

By default properties from different sources are added to the Spring

Environment

in a defined order

(see

Chapter 24, Externalized Configuration

in the ‘Spring Boot features’ section for the exact order).

A nice way to augment and modify this is to add

@PropertySource

annotations to your application sources. Classes passed to the

SpringApplication

static convenience methods, and those added using setSources()

are inspected to see if they have

@PropertySources

, and if they do, those properties are added to the

Environment

early enough to be used in all phases of the

ApplicationContext

lifecycle. Properties added in this way have lower priority than any added using the default locations (e.g. application.properties

), system properties, environment variables or the command line.

You can also provide System properties (or environment variables) to change the behavior:

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• spring.config.name

(

SPRING_CONFIG_NAME

), defaults to application

as the root of the file name.

• spring.config.location

(

SPRING_CONFIG_LOCATION

) is the file to load (e.g. a classpath resource or a URL). A separate

Environment

property source is set up for this document and it can be overridden by system properties, environment variables or the command line.

No matter what you set in the environment, Spring Boot will always load application.properties

as described above. If YAML is used then files with the ‘.yml’ extension are also added to the list by default.

Spring Boot logs the configuration files that are loaded at

DEBUG

level and the candidates it has not found at

TRACE

level.

See

ConfigFileApplicationListener

for more detail.

69.3 Use ‘short’ command line arguments

Some people like to use (for example)

--port=9000

instead of

--server.port=9000

to set configuration properties on the command line. You can easily enable this by using placeholders in application.properties

, e.g.

server.port

=${port:8080}

Tip

If you are inheriting from the spring-boot-starter-parent

POM, the default filter token of the maven-resources-plugins

has been changed from

${*}

to

@

(i.e.

@[email protected] instead of

${maven.token}

) to prevent conflicts with Spring-style placeholders. If you have enabled maven filtering for the application.properties

directly, you may want to also change the default filter token to use other delimiters .

Note

In this specific case the port binding will work in a PaaS environment like Heroku and Cloud

Foundry, since in those two platforms the

PORT

environment variable is set automatically and

Spring can bind to capitalized synonyms for

Environment

properties.

69.4 Use YAML for external properties

YAML is a superset of JSON and as such is a very convenient syntax for storing external properties in a hierarchical format. E.g.

spring

:

application

:

name

: cruncher

datasource

:

driverClassName

: com.mysql.jdbc.Driver

url

: jdbc:mysql://localhost/test

server

:

port

: 9000

Create a file called application.yml

and stick it in the root of your classpath, and also add snakeyaml

to your dependencies (Maven coordinates org.yaml:snakeyaml

, already included if

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). A YAML file is parsed to a Java

Map<String,Object>

(like a JSON object), and Spring Boot flattens the map so that it is 1-level deep and has period-separated keys, a lot like people are used to with

Properties

files in Java.

The example YAML above corresponds to an application.properties

file

spring.application.name

=cruncher

spring.datasource.driverClassName

=com.mysql.jdbc.Driver

spring.datasource.url

=jdbc:mysql://localhost/test

server.port

=9000

See

Section 24.6, “Using YAML instead of Properties”

in the ‘Spring Boot features’ section for more

information about YAML.

69.5 Set the active Spring profiles

The Spring

Environment

has an API for this, but normally you would set a System property

( spring.profiles.active

) or an OS environment variable (

SPRING_PROFILES_ACTIVE

). E.g.

launch your application with a

-D

argument (remember to put it before the main class or jar archive):

$ java -jar -Dspring.profiles.active=production demo-0.0.1-SNAPSHOT.jar

In Spring Boot you can also set the active profile in application.properties

, e.g.

spring.profiles.active

=production

A value set this way is replaced by the System property or environment variable setting, but not by the

SpringApplicationBuilder.profiles()

method. Thus the latter Java API can be used to augment the profiles without changing the defaults.

See

Chapter 25, Profiles

in the ‘Spring Boot features’ section for more information.

69.6 Change configuration depending on the environment

A YAML file is actually a sequence of documents separated by

---

lines, and each document is parsed separately to a flattened map.

If a YAML document contains a spring.profiles

key, then the profiles value (comma-separated list of profiles) is fed into the Spring

Environment.acceptsProfiles()

and if any of those profiles is active that document is included in the final merge (otherwise not).

Example:

server

:

port

: 9000

---

spring

:

profiles

: development

server

:

port

: 9001

---

spring

:

profiles

: production

server

:

port

: 0

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In this example the default port is 9000, but if the Spring profile ‘development’ is active then the port is

9001, and if ‘production’ is active then it is 0.

The YAML documents are merged in the order they are encountered (so later values override earlier ones).

To do the same thing with properties files you can use application-${profile}.properties

to specify profile-specific values.

69.7 Discover built-in options for external properties

Spring Boot binds external properties from application.properties

(or

.yml

) (and other places) into an application at runtime. There is not (and technically cannot be) an exhaustive list of all supported properties in a single location because contributions can come from additional jar files on your classpath.

A running application with the Actuator features has a configprops

endpoint that shows all the bound and bindable properties available through

@ConfigurationProperties

.

The appendix includes an

application.properties

example with a list of the most common properties supported by Spring Boot. The definitive list comes from searching the source code for

@ConfigurationProperties

and

@Value

annotations, as well as the occasional use of

RelaxedPropertyResolver

.

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70. Embedded servlet containers

70.1 Add a Servlet, Filter or Listener to an application

There are two ways to add

Servlet

,

Filter

,

ServletContextListener

and the other listeners supported by the Servlet spec to your application. You can either provide Spring beans for them, or enable scanning for Servlet components.

Add a Servlet, Filter or Listener using a Spring bean

To add a

Servlet

,

Filter

, or Servlet

*Listener

provide a

@Bean

definition for it. This can be very useful when you want to inject configuration or dependencies. However, you must be very careful that they don’t cause eager initialization of too many other beans because they have to be installed in the container very early in the application lifecycle (e.g. it’s not a good idea to have them depend on your

DataSource

or JPA configuration). You can work around restrictions like that by initializing them lazily when first used instead of on initialization.

In the case of

Filters

and

Servlets

you can also add mappings and init parameters by adding a

FilterRegistrationBean

or

ServletRegistrationBean

instead of or as well as the underlying component.

Note

If no dispatcherType

is specified on a filter registration, it will match

FORWARD

,

INCLUDE

and

REQUEST

. If async has been enabled, it will match

ASYNC

as well.

If you are migrating a filter that has no dispatcher

element in web.xml

you will need to specify a dispatcherType

yourself:

@Bean

public

FilterRegistrationBean myFilterRegistration() {

FilterRegistrationBean registration =

new

FilterRegistrationBean();

registration.setDispatcherTypes(DispatcherType.REQUEST);

....

return

registration;

}

Disable registration of a Servlet or Filter

As

described above any

Servlet

or

Filter

beans will be registered with the servlet container automatically. To disable registration of a particular

Filter

or

Servlet

bean create a registration bean for it and mark it as disabled. For example:

@Bean

public

FilterRegistrationBean registration(MyFilter filter) {

FilterRegistrationBean registration =

new

FilterRegistrationBean(filter);

registration.setEnabled(false);

return

registration;

}

Add Servlets, Filters, and Listeners using classpath scanning

@WebServlet

,

@WebFilter

, and

@WebListener

annotated classes can be automatically registered with an embedded servlet container by annotating a

@Configuration

class with

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@ServletComponentScan

and specifying the package(s) containing the components that you want to register. By default,

@ServletComponentScan

will scan from the package of the annotated class.

70.2 Change the HTTP port

In a standalone application the main HTTP port defaults to

8080

, but can be set with server.port

(e.g.

in application.properties

or as a System property). Thanks to relaxed binding of

Environment values you can also use

SERVER_PORT

(e.g. as an OS environment variable).

To switch off the HTTP endpoints completely, but still create a

WebApplicationContext

, use server.port=-1

(this is sometimes useful for testing).

For more details look at

the section called “Customizing embedded servlet containers”

in the ‘Spring

Boot features’ section, or the

ServerProperties

source code.

70.3 Use a random unassigned HTTP port

To scan for a free port (using OS natives to prevent clashes) use server.port=0

.

70.4 Discover the HTTP port at runtime

You can access the port the server is running on from log output or from the

EmbeddedWebApplicationContext

via its

EmbeddedServletContainer

. The best way to get that and be sure that it has initialized is to add a

@Bean

of type

ApplicationListener<EmbeddedServletContainerInitializedEvent>

and pull the container out of the event when it is published.

A useful practice for use with

@WebIntegrationTest

is to set server.port=0

and then inject the actual (‘local’) port as a

@Value

. For example:

@RunWith(SpringJUnit4ClassRunner.class)

@SpringApplicationConfiguration(SampleDataJpaApplication.class)

@WebIntegrationTest("server.port:0")

public class

CityRepositoryIntegrationTests {

@Autowired

EmbeddedWebApplicationContext server;

@Value("${local.server.port}")

int

port;

// ...

}

Note

Don’t try to inject the port with

@Value

in a regular application. As we just saw, the value is only set once the container has initialized; contrary to a test, application code callbacks are processed early (i.e. before the value is actually available).

70.5 Configure SSL

SSL can be configured declaratively by setting the various server.ssl.*

properties, typically in application.properties

or application.yml

. For example:

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server.port

=8443

server.ssl.key-store

=classpath:keystore.jks

server.ssl.key-store-password

=secret

server.ssl.key-password

=another-secret

See

Ssl

for details of all of the supported properties.

Using configuration like the example above means the application will no longer support plain HTTP connector at port 8080. Spring Boot doesn’t support the configuration of both an HTTP connector and an HTTPS connector via application.properties

. If you want to have both then you’ll need to configure one of them programmatically. It’s recommended to use application.properties

to configure HTTPS as the HTTP connector is the easier of the two to configure programmatically. See the spring-boot-sample-tomcat-multi-connectors

sample project for an example.

70.6 Use behind a front-end proxy server

Your application might need to send

302

redirects or render content with absolute links back to itself.

When running behind a proxy, the caller wants a link to the proxy, and not to the physical address of the machine hosting your app. Typically such situations are handled via a contract with the proxy, which will add headers to tell the back end how to construct links to itself.

If the proxy adds conventional

X-Forwarded-For

and

X-Forwarded-Proto

headers (most do this out of the box) the absolute links should be rendered correctly as long as server.use-forwardheaders

is set to true

in your application.properties

.

Note

If your application is running in Cloud Foundry or Heroku the server.use-forward-headers property will default to true

if not specified. In all other instances it defaults to false

.

Customize Tomcat’s proxy configuration

If you are using Tomcat you can additionally configure the names of the headers used to carry

“forwarded” information: server.tomcat.remote-ip-header=x-your-remote-ip-header server.tomcat.protocol-header=x-your-protocol-header

Tomcat is also configured with a default regular expression that matches internal proxies that are to be trusted. By default, IP addresses in

10/8

,

192.168/16

,

169.254/16

and

127/8

are trusted. You can customize the valve’s configuration by adding an entry to application.properties

, e.g.

server.tomcat.internal-proxies=192\\.168\\.\\d{1,3}\\.\\d{1,3}

Note

The double backslashes are only required when you’re using a properties file for configuration.

If you are using YAML, single backslashes are sufficient and a value that’s equivalent to the one shown above would be

192\.168\.\d{1,3}\.\d{1,3}

.

Note

You can trust all proxies by setting the internal-proxies

to empty (but don’t do this in production).

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You can take complete control of the configuration of Tomcat’s

RemoteIpValve

by switching the automatic one off (i.e. set server.use-forward-headers=false

) and adding a new valve instance in a

TomcatEmbeddedServletContainerFactory

bean.

70.7 Configure Tomcat

Generally you can follow the advice from

Section 69.7, “Discover built-in options for external properties”

about

@ConfigurationProperties

(

ServerProperties

is the main one here), but also look at

EmbeddedServletContainerCustomizer

and various Tomcat-specific

*Customizers

that you can add in one of those. The Tomcat APIs are quite rich so once you have access to the

TomcatEmbeddedServletContainerFactory

you can modify it in a number of ways. Or the nuclear option is to add your own

TomcatEmbeddedServletContainerFactory

.

70.8 Enable Multiple Connectors with Tomcat

Add a org.apache.catalina.connector.Connector

to the

TomcatEmbeddedServletContainerFactory

which can allow multiple connectors, e.g. HTTP and

HTTPS connector:

@Bean

public

EmbeddedServletContainerFactory servletContainer() {

TomcatEmbeddedServletContainerFactory tomcat =

new

TomcatEmbeddedServletContainerFactory();

tomcat.addAdditionalTomcatConnectors(createSslConnector());

return

tomcat;

}

private

Connector createSslConnector() {

Connector connector =

new

Connector(

"org.apache.coyote.http11.Http11NioProtocol"

);

Http11NioProtocol protocol = (Http11NioProtocol) connector.getProtocolHandler();

try

{

File keystore =

new

ClassPathResource(

"keystore"

).getFile();

File truststore =

new

ClassPathResource(

"keystore"

).getFile();

connector.setScheme(

"https"

);

connector.setSecure(true);

connector.setPort(8443);

protocol.setSSLEnabled(true);

protocol.setKeystoreFile(keystore.getAbsolutePath());

protocol.setKeystorePass(

"changeit"

);

protocol.setTruststoreFile(truststore.getAbsolutePath());

protocol.setTruststorePass(

"changeit"

);

protocol.setKeyAlias(

"apitester"

);

return

connector;

}

catch

(IOException ex) {

throw new

IllegalStateException(

"can't access keystore: ["

+

"keystore"

+

"] or truststore: ["

+

"keystore"

+

"]"

, ex);

}

}

70.9 Use Jetty instead of Tomcat

The Spring Boot starters ( spring-boot-starter-web

in particular) use Tomcat as an embedded container by default. You need to exclude those dependencies and include the Jetty one instead. Spring

Boot provides Tomcat and Jetty dependencies bundled together as separate starters to help make this process as easy as possible.

Example in Maven:

<dependency>

<groupId>

org.springframework.boot

</groupId>

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<artifactId>

spring-boot-starter-web

</artifactId>

<exclusions>

<exclusion>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter-tomcat

</artifactId>

</exclusion>

</exclusions>

</dependency>

<dependency>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter-jetty

</artifactId>

</dependency>

Example in Gradle: configurations {

compile.exclude module:

"spring-boot-starter-tomcat"

} dependencies {

compile(

"org.springframework.boot:spring-boot-starter-web:1.3.1.BUILD-SNAPSHOT"

)

compile(

"org.springframework.boot:spring-boot-starter-jetty:1.3.1.BUILD-SNAPSHOT"

)

// ...

}

70.10 Configure Jetty

Generally you can follow the advice from

Section 69.7, “Discover built-in options for external properties”

about

@ConfigurationProperties

(

ServerProperties

is the main one here), but also look at

EmbeddedServletContainerCustomizer

. The Jetty APIs are quite rich so once you have access to the

JettyEmbeddedServletContainerFactory

you can modify it in a number of ways. Or the nuclear option is to add your own

JettyEmbeddedServletContainerFactory

.

70.11 Use Undertow instead of Tomcat

Using Undertow instead of Tomcat is very similar to using Jetty instead of Tomcat . You need to exclude

the Tomcat dependencies and include the Undertow starter instead.

Example in Maven:

<dependency>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter-web

</artifactId>

<exclusions>

<exclusion>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter-tomcat

</artifactId>

</exclusion>

</exclusions>

</dependency>

<dependency>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter-undertow

</artifactId>

</dependency>

Example in Gradle: configurations {

compile.exclude module:

"spring-boot-starter-tomcat"

} dependencies {

compile(

"org.springframework.boot:spring-boot-starter-web:1.3.1.BUILD-SNAPSHOT"

)

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compile(

"org.springframework.boot:spring-boot-starter-undertow:1.3.1.BUILD-SNAPSHOT"

)

// ...

}

70.12 Configure Undertow

Generally you can follow the advice from

Section 69.7, “Discover built-in options for external properties”

about

@ConfigurationProperties

(

ServerProperties

and

ServerProperties.Undertow

are the main ones here), but also look at

EmbeddedServletContainerCustomizer

. Once you have access to the

UndertowEmbeddedServletContainerFactory

you can use an

UndertowBuilderCustomizer

to modify Undertow’s configuration to meet your needs. Or the nuclear option is to add your own

UndertowEmbeddedServletContainerFactory

.

70.13 Enable Multiple Listeners with Undertow

Add an

UndertowBuilderCustomizer

to the

UndertowEmbeddedServletContainerFactory and add a listener to the

Builder

:

@Bean

public

UndertowEmbeddedServletContainerFactory embeddedServletContainerFactory() {

UndertowEmbeddedServletContainerFactory factory =

new

UndertowEmbeddedServletContainerFactory();

factory.addBuilderCustomizers(

new

UndertowBuilderCustomizer() {

@Override

public void

customize(Builder builder) {

builder.addHttpListener(8080,

"0.0.0.0"

);

}

});

return

factory;

}

70.14 Use Tomcat 7

Tomcat 7 works with Spring Boot, but the default is to use Tomcat 8. If you cannot use Tomcat 8 (for example, because you are using Java 1.6) you will need to change your classpath to reference Tomcat

7 .

Use Tomcat 7 with Maven

If you are using the starter poms and parent you can just change the Tomcat version property, e.g. for a simple webapp or service:

<properties>

<tomcat.version>

7.0.59

</tomcat.version>

</properties>

<dependencies>

...

<dependency>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter-web

</artifactId>

</dependency>

...

</dependencies>

Use Tomcat 7 with Gradle

You can change the Tomcat version by setting the tomcat.version

property:

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'tomcat.version'

] =

'7.0.59'

dependencies {

compile

'org.springframework.boot:spring-boot-starter-web'

}

70.15 Use Jetty 8

Jetty 8 works with Spring Boot, but the default is to use Jetty 9. If you cannot use Jetty 9 (for example, because you are using Java 1.6) you will need to change your classpath to reference Jetty 8. You will also need to exclude Jetty’s WebSocket-related dependencies.

Use Jetty 8 with Maven

If you are using the starter poms and parent you can just add the Jetty starter with the required

WebSocket exclusion and change the version properties, e.g. for a simple webapp or service:

<properties>

<jetty.version>

8.1.15.v20140411

</jetty.version>

<jetty-jsp.version>

2.2.0.v201112011158

</jetty-jsp.version>

</properties>

<dependencies>

<dependency>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter-web

</artifactId>

<exclusions>

<exclusion>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter-tomcat

</artifactId>

</exclusion>

</exclusions>

</dependency>

<dependency>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter-jetty

</artifactId>

<exclusions>

<exclusion>

<groupId>

org.eclipse.jetty.websocket

</groupId>

<artifactId>

*

</artifactId>

</exclusion>

</exclusions>

</dependency>

</dependencies>

Use Jetty 8 with Gradle

You can set the jetty.version

property and exclude the WebSocket dependency, e.g. for a simple webapp or service: ext[

'jetty.version'

] =

'8.1.15.v20140411'

dependencies {

compile (

'org.springframework.boot:spring-boot-starter-web'

) {

exclude group:

'org.springframework.boot'

, module:

'spring-boot-starter-tomcat'

}

compile (

'org.springframework.boot:spring-boot-starter-jetty'

) {

exclude group:

'org.eclipse.jetty.websocket'

}

}

70.16 Create WebSocket endpoints using @ServerEndpoint

If you want to use

@ServerEndpoint

in a Spring Boot application that used an embedded container, you must declare a single

ServerEndpointExporter @Bean

:

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@Bean

public

ServerEndpointExporter serverEndpointExporter() {

return new

ServerEndpointExporter();

}

This bean will register any

@ServerEndpoint

annotated beans with the underlying WebSocket container. When deployed to a standalone servlet container this role is performed by a servlet container initializer and the

ServerEndpointExporter

bean is not required.

70.17 Enable HTTP response compression

HTTP response compression is supported by Jetty, Tomcat, and Undertow. It can be enabled via application.properties

:

server.compression.enabled

=true

By default, responses must be at least 2048 bytes in length for compression to be performed. This can be configured using the server.compression.min-response-size

property.

By default, responses will only be compressed if their content type is one of the following:

• text/html

• text/xml

• text/plain

• text/css

This can be configured using the server.compression.mime-types

property.

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71. Spring MVC

71.1 Write a JSON REST service

Any Spring

@RestController

in a Spring Boot application should render JSON response by default as long as Jackson2 is on the classpath. For example:

@RestController

public class

MyController {

@RequestMapping("/thing")

public

MyThing thing() {

return new

MyThing();

}

}

As long as

MyThing

can be serialized by Jackson2 (e.g. a normal POJO or Groovy object) then localhost:8080/thing

will serve a JSON representation of it by default. Sometimes in a browser you might see XML responses because browsers tend to send accept headers that prefer XML.

71.2 Write an XML REST service

If you have the Jackson XML extension ( jackson-dataformat-xml

) on the classpath, it will be used to render XML responses and the very same example as we used for JSON would work. To use it, add the following dependency to your project:

<dependency>

<groupId>

com.fasterxml.jackson.dataformat

</groupId>

<artifactId>

jackson-dataformat-xml

</artifactId>

</dependency>

You may also want to add a dependency on Woodstox. It’s faster than the default StAX implementation provided by the JDK and also adds pretty print support and improved namespace handling:

<dependency>

<groupId>

org.codehaus.woodstox

</groupId>

<artifactId>

woodstox-core-asl

</artifactId>

</dependency>

If Jackson’s XML extension is not available, JAXB (provided by default in the JDK) will be used, with the additional requirement to have

MyThing

annotated as

@XmlRootElement

:

@XmlRootElement

public class

MyThing {

private

String name;

// .. getters and setters

}

To get the server to render XML instead of JSON you might have to send an

Accept: text/xml header (or use a browser).

71.3 Customize the Jackson ObjectMapper

Spring MVC (client and server side) uses

HttpMessageConverters

to negotiate content conversion in an HTTP exchange. If Jackson is on the classpath you already get the default converter(s) provided by

Jackson2ObjectMapperBuilder

.

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The

ObjectMapper

(or

XmlMapper

for Jackson XML converter) instance created by default have the following customized properties:

MapperFeature.DEFAULT_VIEW_INCLUSION

is disabled

DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES

is disabled

Spring Boot has also some features to make it easier to customize this behavior.

You can configure the

ObjectMapper

and

XmlMapper

instances using the environment. Jackson provides an extensive suite of simple on/off features that can be used to configure various aspects of its processing. These features are described in six enums in Jackson which map onto properties in the environment:

Jackson enum Environment property

false false false false false inclusion=always|non_null| non_absent|non_default|non_empty

For example, to enable pretty print, set spring.jackson.serialization.indent_output=true

. Note that, thanks to the use of relaxed binding

, the case of indent_output

doesn’t have to match the case of the corresponding enum constant which is

INDENT_OUTPUT

.

If you want to replace the default

ObjectMapper

completely, define a

@Bean

of that type and mark it as

@Primary

.

Defining a

@Bean

of type

Jackson2ObjectMapperBuilder

will allow you to customize both default

ObjectMapper

and

XmlMapper

(used in

MappingJackson2HttpMessageConverter

and

MappingJackson2XmlHttpMessageConverter

respectively).

Another way to customize Jackson is to add beans of type com.fasterxml.jackson.databind.Module

to your context. They will be registered with every bean of type

ObjectMapper

, providing a global mechanism for contributing custom modules when you add new features to your application.

Finally, if you provide any

@Beans

of type

MappingJackson2HttpMessageConverter

then they will replace the default value in the MVC configuration. Also, a convenience bean is provided of type

HttpMessageConverters

(always available if you use the default MVC configuration) which has some useful methods to access the default and user-enhanced message converters.

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See also the

Section 71.4, “Customize the @ResponseBody rendering”

section and the

WebMvcAutoConfiguration

source code for more details.

71.4 Customize the @ResponseBody rendering

Spring uses

HttpMessageConverters

to render

@ResponseBody

(or responses from

@RestController

). You can contribute additional converters by simply adding beans of that type in a

Spring Boot context. If a bean you add is of a type that would have been included by default anyway (like

MappingJackson2HttpMessageConverter

for JSON conversions) then it will replace the default value. A convenience bean is provided of type

HttpMessageConverters

(always available if you use the default MVC configuration) which has some useful methods to access the default and userenhanced message converters (useful, for example if you want to manually inject them into a custom

RestTemplate

).

As in normal MVC usage, any

WebMvcConfigurerAdapter

beans that you provide can also contribute converters by overriding the configureMessageConverters

method, but unlike with normal MVC, you can supply only additional converters that you need (because Spring Boot uses the same mechanism to contribute its defaults). Finally, if you opt-out of the Spring

Boot default MVC configuration by providing your own

@EnableWebMvc

configuration, then you can take control completely and do everything manually using getMessageConverters

from

WebMvcConfigurationSupport

.

See the

WebMvcAutoConfiguration

source code for more details.

71.5 Handling Multipart File Uploads

Spring Boot embraces the Servlet 3 javax.servlet.http.Part

API to support uploading files. By default Spring Boot configures Spring MVC with a maximum file of 1Mb per file and a maximum of

10Mb of file data in a single request. You may override these values, as well as the location to which intermediate data is stored (e.g., to the

/tmp

directory) and the threshold past which data is flushed to disk by using the properties exposed in the

MultipartProperties

class. If you want to specify that files be unlimited, for example, set the multipart.maxFileSize

property to

-1

.

The multipart support is helpful when you want to receive multipart encoded file data as a

@RequestParam

-annotated parameter of type

MultipartFile

in a Spring MVC controller handler method.

See the

MultipartAutoConfiguration

source for more details.

71.6 Switch off the Spring MVC DispatcherServlet

Spring Boot wants to serve all content from the root of your application

/

down. If you would rather map your own servlet to that URL you can do it, but of course you may lose some of the other Boot MVC features. To add your own servlet and map it to the root resource just declare a

@Bean

of type

Servlet and give it the special bean name dispatcherServlet

(You can also create a bean of a different type with that name if you want to switch it off and not replace it).

71.7 Switch off the Default MVC configuration

The easiest way to take complete control over MVC configuration is to provide your own

@Configuration

with the

@EnableWebMvc

annotation. This will leave all MVC configuration in your hands.

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71.8 Customize ViewResolvers

A

ViewResolver

is a core component of Spring MVC, translating view names in

@Controller to actual

View

implementations. Note that

ViewResolvers

are mainly used in UI applications, rather than REST-style services (a

View

is not used to render a

@ResponseBody

). There are many implementations of

ViewResolver

to choose from, and Spring on its own is not opinionated about which ones you should use. Spring Boot, on the other hand, installs one or two for you depending on what it finds on the classpath and in the application context. The

DispatcherServlet

uses all the resolvers it finds in the application context, trying each one in turn until it gets a result, so if you are adding your own you have to be aware of the order and in which position your resolver is added.

WebMvcAutoConfiguration

adds the following

ViewResolvers

to your context:

• An

InternalResourceViewResolver

with bean id ‘defaultViewResolver’. This one locates physical resources that can be rendered using the

DefaultServlet

(e.g. static resources and JSP pages if you are using those). It applies a prefix and a suffix to the view name and then looks for a physical resource with that path in the servlet context (defaults are both empty, but accessible for external configuration via spring.mvc.view.prefix

and spring.mvc.view.suffix

). It can be overridden by providing a bean of the same type.

• A

BeanNameViewResolver

with id ‘beanNameViewResolver’. This is a useful member of the view resolver chain and will pick up any beans with the same name as the

View

being resolved. It shouldn’t be necessary to override or replace it.

• A

ContentNegotiatingViewResolver

with id ‘viewResolver’ is only added if there are actually beans of type

View

present. This is a ‘master’ resolver, delegating to all the others and attempting to find a match to the ‘Accept’ HTTP header sent by the client. There is a useful blog about

ContentNegotiatingViewResolver

that you might like to study to learn more, and also look at the source code for detail. You can switch off the auto-configured

ContentNegotiatingViewResolver

by defining a bean named ‘viewResolver’.

• If you use Thymeleaf you will also have a

ThymeleafViewResolver

with id

‘thymeleafViewResolver’. It looks for resources by surrounding the view name with a prefix and suffix (externalized to spring.thymeleaf.prefix

and spring.thymeleaf.suffix

, defaults

‘classpath:/templates/’ and ‘.html’ respectively). It can be overridden by providing a bean of the same name.

• If you use FreeMarker you will also have a

FreeMarkerViewResolver

with id

‘freeMarkerViewResolver’. It looks for resources in a loader path (externalized to spring.freemarker.templateLoaderPath

, default ‘classpath:/templates/’) by surrounding the view name with a prefix and suffix (externalized to spring.freemarker.prefix

and spring.freemarker.suffix

, with empty and ‘.ftl’ defaults respectively). It can be overridden by providing a bean of the same name.

• If you use Groovy templates (actually if groovy-templates is on your classpath) you will also have a

GroovyMarkupViewResolver

with id ‘groovyMarkupViewResolver’. It looks for resources in a loader path by surrounding the view name with a prefix and suffix (externalized to spring.groovy.template.prefix

and spring.groovy.template.suffix

, defaults

‘classpath:/templates/’ and ‘.tpl’ respectively). It can be overridden by providing a bean of the same name.

• If you use Velocity you will also have a

VelocityViewResolver

with id ‘velocityViewResolver’. It looks for resources in a loader path (externalized to spring.velocity.resourceLoaderPath

,

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and spring.velocity.suffix

, with empty and ‘.vm’ defaults respectively). It can be overridden by providing a bean of the same name.

Check out

WebMvcAutoConfiguration

,

FreeMarkerAutoConfiguration

,

ThymeleafAutoConfiguration

GroovyTemplateAutoConfiguration and

,

VelocityAutoConfiguration

71.9 Velocity

By default, Spring Boot configures a

VelocityViewResolver

. If you need a

VelocityLayoutViewResolver

instead, you can easily configure your own by creating a bean with name velocityViewResolver

. You can also inject the

VelocityProperties

instance to apply the base defaults to your custom view resolver.

The following example replaces the auto-configured velocity view resolver with a

VelocityLayoutViewResolver

defining a customized layoutUrl

and all settings that would have been applied from the auto-configuration:

@Bean(name = "velocityViewResolver")

public

VelocityLayoutViewResolver velocityViewResolver(VelocityProperties properties) {

VelocityLayoutViewResolver resolver =

new

VelocityLayoutViewResolver();

properties.applyToViewResolver(resolver);

resolver.setLayoutUrl(

"layout/default.vm"

);

return

resolver;

}

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72. Logging

Spring Boot has no mandatory logging dependency, except for the commons-logging

API, of which there are many implementations to choose from. To use Logback you need to include it, and some bindings for commons-logging

on the classpath. The simplest way to do that is through the starter poms which all depend on spring-boot-starter-logging

. For a web application you only need spring-boot-starter-web

since it depends transitively on the logging starter. For example, using

Maven:

<dependency>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter-web

</artifactId>

</dependency>

Spring Boot has a

LoggingSystem

abstraction that attempts to configure logging based on the content of the classpath. If Logback is available it is the first choice.

If the only change you need to make to logging is to set the levels of various loggers then you can do that in application.properties

using the "logging.level" prefix, e.g.

logging.level.org.springframework.web

=DEBUG

logging.level.org.hibernate

=ERROR

You can also set the location of a file to log to (in addition to the console) using "logging.file".

To configure the more fine-grained settings of a logging system you need to use the native configuration format supported by the

LoggingSystem

in question. By default Spring Boot picks up the native configuration from its default location for the system (e.g. classpath:logback.xml

for Logback), but you can set the location of the config file using the "logging.config" property.

72.1 Configure Logback for logging

If you put a logback.xml

in the root of your classpath it will be picked up from there (or logbackspring.xml

to take advantage of the templating features provided by Boot). Spring Boot provides a default base configuration that you can include if you just want to set levels, e.g.

<?xml version="1.0" encoding="UTF-8"?>

<configuration>

<include resource

=

"org/springframework/boot/logging/logback/base.xml" />

<logger name

=

"org.springframework.web" level

=

"DEBUG" />

</configuration>

If you look at that base.xml

in the spring-boot jar, you will see that it uses some useful System properties which the

LoggingSystem

takes care of creating for you. These are:

${PID}

the current process ID.

${LOG_FILE}

if logging.file

was set in Boot’s external configuration.

${LOG_PATH}

if logging.path

was set (representing a directory for log files to live in).

${LOG_EXCEPTION_CONVERSION_WORD}

if logging.exception-conversion-word

was set in Boot’s external configuration.

Spring Boot also provides some nice ANSI colour terminal output on a console (but not in a log file) using a custom Logback converter. See the default base.xml

configuration for details.

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If Groovy is on the classpath you should be able to configure Logback with logback.groovy

as well

(it will be given preference if present).

Configure logback for file only output

If you want to disable console logging and write output only to a file you need a custom springlogback.xml

that imports file-appender.xml

but not console-appender.xml

:

<?xml version="1.0" encoding="UTF-8"?>

<configuration>

<include resource

=

"org/springframework/boot/logging/logback/defaults.xml" />

<property name

=

"LOG_FILE" value

=

"${LOG_FILE:-${LOG_PATH:-${LOG_TEMP:-${java.io.tmpdir:-/ tmp}}/}spring.log}" />

<include resource

=

"org/springframework/boot/logging/logback/file-appender.xml" />

<root level

=

"INFO" >

<appender-ref ref

=

"FILE" />

</root>

</configuration>

You also need to add logging.file

to your application.properties

:

logging.file

=myapplication.log

72.2 Configure Log4j for logging

Spring Boot also supports either Log4j or Log4j 2 for logging configuration, but only if one of them is on the classpath. If you are using the starter poms for assembling dependencies that means you have to exclude Logback and then include your chosen version of Log4j instead. If you aren’t using the starter poms then you need to provide commons-logging

(at least) in addition to your chosen version of Log4j.

The simplest path is probably through the starter poms, even though it requires some jiggling with excludes, .e.g. in Maven:

<dependency>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter-web

</artifactId>

</dependency>

<dependency>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter

</artifactId>

<exclusions>

<exclusion>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter-logging

</artifactId>

</exclusion>

</exclusions>

</dependency>

<dependency>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter-log4j

</artifactId>

</dependency>

To use Log4j 2, simply depend on spring-boot-starter-log4j2

rather than spring-bootstarter-log4j

.

Note

The use of one of the Log4j starters gathers together the dependencies for common logging requirements (e.g. including having Tomcat use java.util.logging

but configuring the output using Log4j or Log4j 2). See the Actuator Log4j or Log4j 2 samples for more detail and to see it in action.

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Use YAML or JSON to configure Log4j 2

In addition to its default XML configuration format, Log4j 2 also supports YAML and JSON configuration files. To configure Log4j 2 to use an alternative configuration file format all you need to do is add an appropriate dependency to the classpath. To use YAML, add a dependency on com.fasterxml.jackson.dataformat:jackson-dataformat-yaml

and Log4j 2 will look for configuration files names log4j2.yaml

or log4j2.yml

. To use JSON, add a dependency on com.fasterxml.jackson.core:jackson-databind

and Log4j 2 will look for configuration files named log4j2.json

or log4j2.jsn

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73. Data Access

73.1 Configure a DataSource

To override the default settings just define a

@Bean

of your own of type

DataSource

. Spring Boot provides a utility builder class

DataSourceBuilder

that can be used to create one of the standard ones (if it is on the classpath), or you can just create your own, and bind it to a set of

Environment

properties as explained in the section called “Third-party configuration” , e.g.

@Bean

@ConfigurationProperties(prefix="datasource.mine")

public

DataSource dataSource() {

return new

FancyDataSource();

}

datasource.mine.jdbcUrl

=jdbc:h2:mem:mydb

datasource.mine.user

=sa

datasource.mine.poolSize

=30

See

Section 29.1, “Configure a DataSource”

in the ‘Spring Boot features’ section and the

DataSourceAutoConfiguration

class for more details.

73.2 Configure Two DataSources

Creating more than one data source works the same as creating the first one. You might want to mark one of them as

@Primary

if you are using the default auto-configuration for JDBC or JPA (then that one will be picked up by any

@Autowired

injections).

@Bean

@Primary

@ConfigurationProperties(prefix="datasource.primary")

public

DataSource primaryDataSource() {

return

DataSourceBuilder.create().build();

}

@Bean

@ConfigurationProperties(prefix="datasource.secondary")

public

DataSource secondaryDataSource() {

return

DataSourceBuilder.create().build();

}

73.3 Use Spring Data repositories

Spring Data can create implementations for you of

@Repository

interfaces of various flavors. Spring

Boot will handle all of that for you as long as those

@Repositories

are included in the same package

(or a sub-package) of your

@EnableAutoConfiguration

class.

For many applications all you will need is to put the right Spring Data dependencies on your classpath

(there is a spring-boot-starter-data-jpa

for JPA and a spring-boot-starter-datamongodb

for Mongodb), create some repository interfaces to handle your

@Entity

objects. Examples are in the JPA sample or the Mongodb sample .

Spring Boot tries to guess the location of your

@Repository

definitions, based on the

@EnableAutoConfiguration

it finds. To get more control, use the

@EnableJpaRepositories annotation (from Spring Data JPA).

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73.4 Separate @Entity definitions from Spring configuration

Spring Boot tries to guess the location of your

@Entity

definitions, based on the

@EnableAutoConfiguration

it finds. To get more control, you can use the

@EntityScan annotation, e.g.

@Configuration

@EnableAutoConfiguration

@EntityScan(basePackageClasses=City.class)

public class

Application {

//...

}

73.5 Configure JPA properties

Spring Data JPA already provides some vendor-independent configuration options (e.g. for SQL logging) and Spring Boot exposes those, and a few more for hibernate as external configuration properties. The most common options to set are: spring.jpa.hibernate.ddl-auto: create-drop spring.jpa.hibernate.naming_strategy: org.hibernate.cfg.ImprovedNamingStrategy

spring.jpa.database: H2 spring.jpa.show-sql: true

(Because of relaxed data binding hyphens or underscores should work equally well as property keys.) The ddl-auto

setting is a special case in that it has different defaults depending on whether you are using an embedded database ( create-drop

) or not ( none

). In addition all properties in spring.jpa.properties.*

are passed through as normal JPA properties (with the prefix stripped) when the local

EntityManagerFactory

is created.

See

HibernateJpaAutoConfiguration

and

JpaBaseConfiguration

for more details.

73.6 Use a custom EntityManagerFactory

To take full control of the configuration of the

EntityManagerFactory

, you need to add a

@Bean named ‘entityManagerFactory’. Spring Boot auto-configuration switches off its entity manager based on the presence of a bean of that type.

73.7 Use Two EntityManagers

Even if the default

EntityManagerFactory

works fine, you will need to define a new one because otherwise the presence of the second bean of that type will switch off the default. To make it easy to do that you can use the convenient

EntityManagerBuilder

provided by Spring Boot, or if you prefer you can just use the

LocalContainerEntityManagerFactoryBean

directly from Spring ORM.

Example:

// add two data sources configured as above

@Bean

public

LocalContainerEntityManagerFactoryBean customerEntityManagerFactory(

EntityManagerFactoryBuilder builder) {

return

builder

.dataSource(customerDataSource())

.packages(Customer.

class

)

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.persistenceUnit(

"customers"

)

.build();

}

@Bean

public

LocalContainerEntityManagerFactoryBean orderEntityManagerFactory(

EntityManagerFactoryBuilder builder) {

return

builder

.dataSource(orderDataSource())

.packages(Order.

class

)

.persistenceUnit(

"orders"

)

.build();

}

The configuration above almost works on its own. To complete the picture you need to configure

TransactionManagers

for the two

EntityManagers

as well. One of them could be picked up by the default

JpaTransactionManager

in Spring Boot if you mark it as

@Primary

. The other would have to be explicitly injected into a new instance. Or you might be able to use a JTA transaction manager spanning both.

If you are using Spring Data, you need to configure

@EnableJpaRepositories

accordingly:

@Configuration

@EnableJpaRepositories(basePackageClasses = Customer.class,

entityManagerFactoryRef = "customerEntityManagerFactory")

public class

CustomerConfiguration {

...

}

@Configuration

@EnableJpaRepositories(basePackageClasses = Order.class,

entityManagerFactoryRef = "orderEntityManagerFactory")

public class

OrderConfiguration {

...

}

73.8 Use a traditional persistence.xml

Spring doesn’t require the use of XML to configure the JPA provider, and Spring Boot assumes you want to take advantage of that feature. If you prefer to use persistence.xml

then you need to define your own

@Bean

of type

LocalEntityManagerFactoryBean

(with id ‘entityManagerFactory’, and set the persistence unit name there.

See

JpaBaseConfiguration

for the default settings.

73.9 Use Spring Data JPA and Mongo repositories

Spring Data JPA and Spring Data Mongo can both create

Repository

implementations for you automatically. If they are both present on the classpath, you might have to do some extra configuration to tell Spring Boot which one (or both) you want to create repositories for you. The most explicit way to do that is to use the standard Spring Data

@Enable*Repositories

and tell it the location of your

Repository

interfaces (where ‘*’ is ‘Jpa’ or ‘Mongo’ or both).

There are also flags spring.data.*.repositories.enabled

that you can use to switch the autoconfigured repositories on and off in external configuration. This is useful for instance in case you want to switch off the Mongo repositories and still use the auto-configured

MongoTemplate

.

The same obstacle and the same features exist for other auto-configured Spring Data repository types

(Elasticsearch, Solr). Just change the names of the annotations and flags respectively.

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73.10 Expose Spring Data repositories as REST endpoint

Spring Data REST can expose the

Repository

implementations as REST endpoints for you as long as Spring MVC has been enabled for the application.

Spring Boot exposes as set of useful properties from the spring.data.rest

namespace that customize the

RepositoryRestConfiguration

. If you need to provide additional customization, you should use a

RepositoryRestConfigurer

bean.

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74. Database initialization

An SQL database can be initialized in different ways depending on what your stack is. Or of course you can do it manually as long as the database is a separate process.

74.1 Initialize a database using JPA

JPA has features for DDL generation, and these can be set up to run on startup against the database.

This is controlled through two external properties:

• spring.jpa.generate-ddl

(boolean) switches the feature on and off and is vendor independent.

• spring.jpa.hibernate.ddl-auto

(enum) is a Hibernate feature that controls the behavior in a more fine-grained way. See below for more detail.

74.2 Initialize a database using Hibernate

You can set spring.jpa.hibernate.ddl-auto

explicitly and the standard Hibernate property values are none

, validate

, update

, create

, create-drop

. Spring Boot chooses a default value for you based on whether it thinks your database is embedded (default create-drop

) or not (default none

). An embedded database is detected by looking at the

Connection

type: hsqldb

, h2

and derby are embedded, the rest are not. Be careful when switching from in-memory to a ‘real’ database that you don’t make assumptions about the existence of the tables and data in the new platform. You either have to set ddl-auto

explicitly, or use one of the other mechanisms to initialize the database.

Note

You can output the schema creation by enabling the org.hibernate.SQL

logger. This is done

for you automatically if you enable the debug mode

.

In addition, a file named import.sql

in the root of the classpath will be executed on startup. This can be useful for demos and for testing if you are careful, but probably not something you want to be on the classpath in production. It is a Hibernate feature (nothing to do with Spring).

74.3 Initialize a database using Spring JDBC

Spring JDBC has a

DataSource

initializer feature. Spring Boot enables it by default and loads

SQL from the standard locations schema.sql

and data.sql

(in the root of the classpath). In addition Spring Boot will load the schema-${platform}.sql

and data-${platform}.sql

files

(if present), where platform

is the value of spring.datasource.platform

, e.g. you might choose to set it to the vendor name of the database ( hsqldb

, h2

, oracle

, mysql

, postgresql etc.). Spring Boot enables the fail-fast feature of the Spring JDBC initializer by default, so if the scripts cause exceptions the application will fail to start. The script locations can be changed by setting spring.datasource.schema

and spring.datasource.data

, and neither location will be processed if spring.datasource.initialize=false

.

To disable the fail-fast you can set spring.datasource.continueOnError=true

. This can be useful once an application has matured and been deployed a few times, since the scripts can act as

‘poor man’s migrations’ — inserts that fail mean that the data is already there, so there would be no need to prevent the application from running, for instance.

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If you want to use the schema.sql

initialization in a JPA app (with Hibernate) then ddlauto=create-drop

will lead to errors if Hibernate tries to create the same tables. To avoid those errors set ddl-auto

explicitly to "" (preferable) or "none". Whether or not you use ddl-auto=createdrop

you can always use data.sql

to initialize new data.

74.4 Initialize a Spring Batch database

If you are using Spring Batch then it comes pre-packaged with SQL initialization scripts for most popular database platforms. Spring Boot will detect your database type, and execute those scripts by default, and in this case will switch the fail fast setting to false (errors are logged but do not prevent the application from starting). This is because the scripts are known to be reliable and generally do not contain bugs, so errors are ignorable, and ignoring them makes the scripts idempotent. You can switch off the initialization explicitly using spring.batch.initializer.enabled=false

.

74.5 Use a higher level database migration tool

Spring Boot works fine with higher level migration tools Flyway (SQL-based) and Liquibase (XML). In general we prefer Flyway because it is easier on the eyes, and it isn’t very common to need platform independence: usually only one or at most couple of platforms is needed.

Execute Flyway database migrations on startup

To automatically run Flyway database migrations on startup, add the org.flywaydb:flyway-core to your classpath.

The migrations are scripts in the form

V<VERSION>__<NAME>.sql

(with

<VERSION>

an underscoreseparated version, e.g. ‘1’ or ‘2_1’). By default they live in a folder classpath:db/migration

but you can modify that using flyway.locations

(a list). See the Flyway class from flyway-core for details of available settings like schemas etc. In addition Spring Boot provides a small set of properties in

FlywayProperties

that can be used to disable the migrations, or switch off the location checking.

By default Flyway will autowire the (

@Primary

)

DataSource

in your context and use that for migrations. If you like to use a different

DataSource

you can create one and mark its

@Bean

as

@FlywayDataSource

- if you do that remember to create another one and mark it as

@Primary if you want two data sources. Or you can use Flyway’s native

DataSource

by setting flyway.

[url,user,password]

in external properties.

There is a Flyway sample so you can see how to set things up.

Execute Liquibase database migrations on startup

To automatically run Liquibase database migrations on startup, add the org.liquibase:liquibase-core

to your classpath.

The master change log is by default read from db/changelog/db.changelog-master.yaml

but can be set using liquibase.change-log

. See

LiquibaseProperties

for details of available settings like contexts, default schema etc.

There is a Liquibase sample so you can see how to set things up.

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75. Batch applications

75.1 Execute Spring Batch jobs on startup

Spring Batch auto-configuration is enabled by adding

@EnableBatchProcessing

(from Spring Batch) somewhere in your context.

By default it executes all

Jobs in the application context on startup (see

JobLauncherCommandLineRunner for details). You can narrow down to a specific job or jobs by specifying spring.batch.job.names

(comma-separated job name patterns).

If the application context includes a

JobRegistry

then the jobs in spring.batch.job.names

are looked up in the registry instead of being autowired from the context. This is a common pattern with more complex systems where multiple jobs are defined in child contexts and registered centrally.

See BatchAutoConfiguration and @EnableBatchProcessing for more details.

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76. Actuator

76.1 Change the HTTP port or address of the actuator endpoints

In a standalone application the Actuator HTTP port defaults to the same as the main HTTP port. To make the application listen on a different port set the external property management.port

. To listen on a completely different network address (e.g. if you have an internal network for management and an external one for user applications) you can also set management.address

to a valid IP address that the server is able to bind to.

For more detail look at the

ManagementServerProperties

source code and

Section 46.3,

“Customizing the management server port”

in the ‘Production-ready features’ section.

76.2 Customize the ‘whitelabel’ error page

Spring Boot installs a ‘whitelabel’ error page that you will see in browser client if you encounter a server error (machine clients consuming JSON and other media types should see a sensible response with the right error code). To switch it off you can set server.error.whitelabel.enabled=false

, but normally in addition or alternatively to that you will want to add your own error page replacing the whitelabel one. Exactly how you do this depends on the templating technology that you are using.

For example, if you are using Thymeleaf you would add an error.html

template and if you are using FreeMarker you would add an error.ftl

template. In general what you need is a

View that resolves with a name of error

, and/or a

@Controller

that handles the

/error

path. Unless you replaced some of the default configuration you should find a

BeanNameViewResolver

in your

ApplicationContext

so a

@Bean

with id error

would be a simple way of doing that. Look at

ErrorMvcAutoConfiguration

for more options.

See also the section on Error Handling for details of how to register handlers in the servlet container.

76.3 Actuator and Jersey

Actuator HTTP endpoints are only available for Spring MVC-based applications. If you want to use

Jersey and still use the actuator you will need to enable Spring MVC (by depending on springboot-starter-web

, for example). By default, both Jersey and the Spring MVC dispatcher servlet are mapped to the same path (

/

). You will need to change the path for one of them (by configuring server.servlet-path

for Spring MVC or spring.jersey.application-path

for Jersey).

For example, if you add server.servlet-path=/system

into application.properties

, the actuator HTTP endpoints will be available under

/system

.

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77. Security

77.1 Switch off the Spring Boot security configuration

If you define a

@Configuration

with

@EnableWebSecurity

anywhere in your application it will switch off the default webapp security settings in Spring Boot. To tweak the defaults try setting properties in security.*

(see

SecurityProperties

for details of available settings) and

SECURITY

section of

Common application properties

.

77.2 Change the AuthenticationManager and add user accounts

If you provide a

@Bean

of type

AuthenticationManager

the default one will not be created, so you have the full feature set of Spring Security available (e.g. various authentication options ).

Spring Security also provides a convenient

AuthenticationManagerBuilder

which can be used to build an

AuthenticationManager

with common options. The recommended way to use this in a webapp is to inject it into a void method in a

WebSecurityConfigurerAdapter

, e.g.

@Configuration

public class

SecurityConfiguration

extends

WebSecurityConfigurerAdapter {

@Autowired

public void

configureGlobal(AuthenticationManagerBuilder auth)

throws

Exception {

auth.inMemoryAuthentication()

.withUser(

"barry"

).password(

"password"

).roles(

"USER"

);

// ... etc.

}

// ... other stuff for application security

}

You will get the best results if you put this in a nested class, or a standalone class (i.e. not mixed in with a lot of other

@Beans

that might be allowed to influence the order of instantiation). The secure web sample is a useful template to follow.

If you experience instantiation issues (e.g. using JDBC or JPA for the user detail store) it might be worth extracting the

AuthenticationManagerBuilder

callback into a

GlobalAuthenticationConfigurerAdapter

(in the init()

method so it happens before the authentication manager is needed elsewhere), e.g.

@Configuration

public class

AuthenticationManagerConfiguration

extends

GlobalAuthenticationConfigurerAdapter {

@Override

public void

init(AuthenticationManagerBuilder auth) {

auth.inMemoryAuthentication()

// ... etc.

}

}

77.3 Enable HTTPS when running behind a proxy server

Ensuring that all your main endpoints are only available over HTTPS is an important chore for any application. If you are using Tomcat as a servlet container, then Spring Boot will add Tomcat’s own

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RemoteIpValve

automatically if it detects some environment settings, and you should be able to rely on the

HttpServletRequest

to report whether it is secure or not (even downstream of a proxy server that handles the real SSL termination). The standard behavior is determined by the presence or absence of certain request headers ( x-forwarded-for

and x-forwarded-proto

), whose names are conventional, so it should work with most front end proxies. You can switch on the valve by adding some entries to application.properties

, e.g.

server.tomcat.remote_ip_header

=x-forwarded-for

server.tomcat.protocol_header

=x-forwarded-proto

(The presence of either of those properties will switch on the valve. Or you can add the

RemoteIpValve yourself by adding a

TomcatEmbeddedServletContainerFactory

bean.)

Spring Security can also be configured to require a secure channel for all (or some requests). To switch that on in a Spring Boot application you just need to set security.require_ssl

to true

in application.properties

.

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78. Hot swapping

78.1 Reload static content

There are several options for hot reloading. Running in an IDE (especially with debugging on) is a good way to do development (all modern IDEs allow reloading of static resources and usually also hotswapping of Java class changes).

The

spring-boot-devtools

module is also available with support for fast application restarts and

LiveReload.

Finally, the Maven and Gradle plugins

can be configured to support running from the command line with reloading of static files. You can use that with an external css/js compiler process if you are writing that code with higher level tools.

78.2 Reload templates without restarting the container

Most of the templating technologies supported by Spring Boot include a configuration option to disable caching (see below for details). If you’re using the spring-boot-devtools

module these properties will be

automatically configured for you at development time.

Thymeleaf templates

If you are using Thymeleaf, then set spring.thymeleaf.cache

to false

. See

ThymeleafAutoConfiguration

for other Thymeleaf customization options.

FreeMarker templates

If you are using FreeMarker, then set spring.freemarker.cache

to false

. See

FreeMarkerAutoConfiguration

for other FreeMarker customization options.

Groovy templates

If you are using Groovy templates, then set spring.groovy.template.cache

to false

. See

GroovyTemplateAutoConfiguration

for other Groovy customization options.

Velocity templates

If you are using Velocity, then set spring.velocity.cache

to false

. See

VelocityAutoConfiguration

for other Velocity customization options.

78.3 Fast application restarts

The spring-boot-devtools

module includes support for automatic application restarts. Whilst not as fast a technologies such as JRebel or Spring Loaded it’s usually significantly faster than a “cold start”. You should probably give it a try before investigating some of the more complex reload options discussed below.

For more details see the

Chapter 20, Developer tools section.

78.4 Reload Java classes without restarting the container

Modern IDEs (Eclipse, IDEA, etc.) all support hot swapping of bytecode, so if you make a change that doesn’t affect class or method signatures it should reload cleanly with no side effects.

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Spring Loaded goes a little further in that it can reload class definitions with changes in the method signatures. With some customization it can force an

ApplicationContext

to refresh itself (but there is no general mechanism to ensure that would be safe for a running application anyway, so it would only ever be a development time trick probably).

Configuring Spring Loaded for use with Maven

To use Spring Loaded with the Maven command line, just add it as a dependency in the Spring Boot plugin declaration, e.g.

<plugin>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-maven-plugin

</artifactId>

<dependencies>

<dependency>

<groupId>

org.springframework

</groupId>

<artifactId>

springloaded

</artifactId>

<version>

1.2.0.RELEASE

</version>

</dependency>

</dependencies>

</plugin>

This normally works pretty well with Eclipse and IntelliJ IDEA as long as they have their build configuration aligned with the Maven defaults (Eclipse m2e does this out of the box).

Configuring Spring Loaded for use with Gradle and IntelliJ IDEA

You need to jump through a few hoops if you want to use Spring Loaded in combination with Gradle and

IntelliJ IDEA. By default, IntelliJ IDEA will compile classes into a different location than Gradle, causing

Spring Loaded monitoring to fail.

To configure IntelliJ IDEA correctly you can use the idea

Gradle plugin: buildscript {

repositories { jcenter() }

dependencies {

classpath

"org.springframework.boot:spring-boot-gradle-plugin:1.3.1.BUILD-SNAPSHOT"

classpath

'org.springframework:springloaded:1.2.0.RELEASE'

}

} apply plugin:

'idea'

idea {

module {

inheritOutputDirs = false

outputDir = file(

"$buildDir/classes/main/"

)

}

}

// ...

Note

IntelliJ IDEA must be configured to use the same Java version as the command line Gradle task and springloaded

must be included as a buildscript

dependency.

You can also additionally enable ‘Make Project Automatically’ inside IntelliJ IDEA to automatically compile your code whenever a file is saved.

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79. Build

79.1 Customize dependency versions

If you use a Maven build that inherits directly or indirectly from spring-boot-dependencies

(for instance spring-boot-starter-parent

) but you want to override a specific third-party dependency you can add appropriate

<properties>

elements. Browse the spring-boot-dependencies

POM for a complete list of properties. For example, to pick a different slf4j

version you would add the following:

<properties>

<slf4j.version>

1.7.5

<slf4j.version>

</properties>

Note

This only works if your Maven project inherits (directly or indirectly) from springboot-dependencies

. If you have added spring-boot-dependencies

in your own dependencyManagement

section with

<scope>import</scope>

you have to redefine the artifact yourself instead of overriding the property.

Warning

Each Spring Boot release is designed and tested against a specific set of third-party dependencies. Overriding versions may cause compatibility issues.

To override dependency versions in Gradle, you can specify a version as shown below: ext[

'slf4j.version'

] =

'1.7.5'

For additional information, please refer to the Gradle Dependency Management Plugin documentation .

79.2 Create an executable JAR with Maven

The spring-boot-maven-plugin

can be used to create an executable ‘fat’ JAR. If you are using the spring-boot-starter-parent

POM you can simply declare the plugin and your jars will be repackaged:

<build>

<plugins>

<plugin>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-maven-plugin

</artifactId>

</plugin>

</plugins>

</build>

If you are not using the parent POM you can still use the plugin, however, you must additionally add an

<executions>

section:

<build>

<plugins>

<plugin>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-maven-plugin

</artifactId>

<version>

1.3.1.BUILD-SNAPSHOT

</version>

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<executions>

<execution>

<goals>

<goal>

repackage

</goal>

</goals>

</execution>

</executions>

</plugin>

</plugins>

</build>

See the plugin documentation for full usage details.

79.3 Create an additional executable JAR

If you want to use your project as a library jar for other projects to depend on, and in addition have an executable (e.g. demo) version of it, you will want to configure the build in a slightly different way.

For Maven the normal JAR plugin and the Spring Boot plugin both have a ‘classifier’ configuration that you can add to create an additional JAR. Example (using the Spring Boot Starter Parent to manage the plugin versions and other configuration defaults):

<build>

<plugins>

<plugin>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-maven-plugin

</artifactId>

<configuration>

<classifier>

exec

</classifier>

</configuration>

</plugin>

</plugins>

</build>

Two jars are produced, the default one, and an executable one using the Boot plugin with classifier

‘exec’.

For Gradle users the steps are similar. Example: bootRepackage {

classifier =

'exec'

}

79.4 Extract specific libraries when an executable jar runs

Most nested libraries in an executable jar do not need to be unpacked in order to run, however, certain libraries can have problems. For example, JRuby includes its own nested jar support which assumes that the jruby-complete.jar

is always directly available as a file in its own right.

To deal with any problematic libraries, you can flag that specific nested jars should be automatically unpacked to the ‘temp folder’ when the executable jar first runs.

For example, to indicate that JRuby should be flagged for unpack using the Maven Plugin you would add the following configuration:

<build>

<plugins>

<plugin>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-maven-plugin

</artifactId>

<configuration>

<requiresUnpack>

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<dependency>

<groupId>

org.jruby

</groupId>

<artifactId>

jruby-complete

</artifactId>

</dependency>

</requiresUnpack>

</configuration>

</plugin>

</plugins>

</build>

And to do that same with Gradle: springBoot {

requiresUnpack = [

'org.jruby:jruby-complete'

]

}

79.5 Create a non-executable JAR with exclusions

Often if you have an executable and a non-executable jar as build products, the executable version will have additional configuration files that are not needed in a library jar. E.g. the application.yml

configuration file might excluded from the non-executable JAR.

Here’s how to do that in Maven:

<build>

<plugins>

<plugin>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-maven-plugin

</artifactId>

<configuration>

<classifier>

exec

</classifier>

</configuration>

</plugin>

<plugin>

<artifactId>

maven-jar-plugin

</artifactId>

<executions>

<execution>

<id>

exec

</id>

<phase>

package

</phase>

<goals>

<goal>

jar

</goal>

</goals>

<configuration>

<classifier>

exec

</classifier>

</configuration>

</execution>

<execution>

<phase>

package

</phase>

<goals>

<goal>

jar

</goal>

</goals>

<configuration>

<!-- Need this to ensure application.yml is excluded -->

<forceCreation>

true

</forceCreation>

<excludes>

<exclude>

application.yml

</exclude>

</excludes>

</configuration>

</execution>

</executions>

</plugin>

</plugins>

</build>

In Gradle you can create a new JAR archive with standard task DSL features, and then have the bootRepackage

task depend on that one using its withJarTask

property:

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baseName =

'spring-boot-sample-profile'

version =

'0.0.0'

excludes = [

'**/application.yml'

]

} task(

'execJar'

, type:Jar, dependsOn:

'jar'

) {

baseName =

'spring-boot-sample-profile'

version =

'0.0.0'

classifier =

'exec'

from sourceSets.main.output

} bootRepackage {

withJarTask = tasks[

'execJar'

]

}

79.6 Remote debug a Spring Boot application started with

Maven

To attach a remote debugger to a Spring Boot application started with Maven you can use the jvmArguments

property of the maven plugin .

Check this example for more details.

79.7 Remote debug a Spring Boot application started with

Gradle

To attach a remote debugger to a Spring Boot application started with Gradle you can use the applicationDefaultJvmArgs

in build.gradle

or

--debug-jvm

command line option.

build.gradle

: applicationDefaultJvmArgs = [

"-agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=5005"

]

Command line:

$ gradle run --debug-jvm

Check Gradle Application Plugin for more details.

79.8 Build an executable archive from Ant without using spring-boot-antlib

To build with Ant you need to grab dependencies, compile and then create a jar or war archive as normal.

To make it executable you can either use the spring-boot-antlib

module, or you can follow these instructions:

1. Use the appropriate launcher as a

Main-Class

, e.g.

JarLauncher

for a jar file, and specify the other properties it needs as manifest entries, principally a

Start-Class

.

2. Add the runtime dependencies in a nested ‘lib’ directory (for a jar) and the provided

(embedded container) dependencies in a nested lib-provided

directory. Remember not to compress the entries in the archive.

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3. Add the spring-boot-loader

classes at the root of the archive (so the

Main-Class

is available).

Example:

<target name

=

"build" depends

=

"compile" >

<copy todir

=

"target/classes/lib" >

<fileset dir

=

"lib/runtime" />

</copy>

<jar destfile

=

"target/spring-boot-sample-actuator-${spring-boot.version}.jar" compress

=

"false" >

<fileset dir

=

"target/classes" />

<fileset dir

=

"src/main/resources" />

<zipfileset src

=

"lib/loader/spring-boot-loader-jar-${spring-boot.version}.jar" />

<manifest>

<attribute name

=

"Main-Class" value

=

"org.springframework.boot.loader.JarLauncher" />

<attribute name

=

"Start-Class" value

=

"${start-class}" />

</manifest>

</jar>

</target>

The Actuator Sample has a build.xml

that should work if you run it with

$ ant -lib <folder containing ivy-2.2.jar> after which you can run the application with

$ java -jar target/*.jar

79.9 How to use Java 6

If you want to use Spring Boot with Java 6 there are a small number of configuration changes that you will have to make. The exact changes depend on your application’s functionality.

Embedded servlet container compatibility

If you are using one of Boot’s embedded Servlet containers you will have to use a Java 6-compatible container. Both Tomcat 7 and Jetty 8 are Java 6 compatible. See

Section 70.14, “Use Tomcat 7”

and

Section 70.15, “Use Jetty 8”

for details.

JTA API compatibility

While the Java Transaction API itself doesn’t require Java 7 the official API jar contains classes that have been built to require Java 7. If you are using JTA then you will need to replace the official JTA 1.2

API jar with one that has been built to work on Java 6. To do so, exclude any transitive dependencies on javax.transaction:javax.transaction-api

and replace them with a dependency on org.jboss.spec.javax.transaction:jboss-transaction-api_1.2_spec:1.0.0.Final

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80. Traditional deployment

80.1 Create a deployable war file

The first step in producing a deployable war file is to provide a

SpringBootServletInitializer subclass and override its configure

method. This makes use of Spring Framework’s Servlet 3.0

support and allows you to configure your application when it’s launched by the servlet container.

Typically, you update your application’s main class to extend

SpringBootServletInitializer

:

@SpringBootApplication

public class

Application

extends

SpringBootServletInitializer {

@Override

protected

SpringApplicationBuilder configure(SpringApplicationBuilder application) {

return

application.sources(Application.

class

);

}

public static void

main(String[] args)

throws

Exception {

SpringApplication.run(Application.

class

, args);

}

}

The next step is to update your build configuration so that your project produces a war file rather than a jar file. If you’re using Maven and using spring-boot-starter-parent

(which configures Maven’s war plugin for you) all you need to do is modify pom.xml

to change the packaging to war:

<packaging>

war

</packaging>

If you’re using Gradle, you need to modify build.gradle

to apply the war plugin to the project: apply plugin:

'war'

The final step in the process is to ensure that the embedded servlet container doesn’t interfere with the servlet container to which the war file will be deployed. To do so, you need to mark the embedded servlet container dependency as provided.

If you’re using Maven:

<dependencies>

<!-- … -->

<dependency>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-starter-tomcat

</artifactId>

<scope>

provided

</scope>

</dependency>

<!-- … -->

</dependencies>

And if you’re using Gradle: dependencies {

// …

providedRuntime

'org.springframework.boot:spring-boot-starter-tomcat'

// …

}

If you’re using the

Spring Boot build tools , marking the embedded servlet container dependency as

provided will produce an executable war file with the provided dependencies packaged in a lib-

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directory. This means that, in addition to being deployable to a servlet container, you can also run your application using java -jar

on the command line.

Tip

Take a look at Spring Boot’s sample applications for a Maven-based example of the abovedescribed configuration.

80.2 Create a deployable war file for older servlet containers

Older Servlet containers don’t have support for the

ServletContextInitializer

bootstrap process used in Servlet 3.0. You can still use Spring and Spring Boot in these containers but you are going to need to add a web.xml

to your application and configure it to load an

ApplicationContext

via a

DispatcherServlet

.

80.3 Convert an existing application to Spring Boot

For a non-web application it should be easy (throw away the code that creates your

ApplicationContext and replace it with calls to

SpringApplication or

SpringApplicationBuilder

). Spring MVC web applications are generally amenable to first creating a deployable war application, and then migrating it later to an executable war and/or jar. Useful reading is in the Getting Started Guide on Converting a jar to a war .

Create a deployable war by extending

SpringBootServletInitializer

(e.g. in a class called

Application

), and add the Spring Boot

@EnableAutoConfiguration

annotation. Example:

@Configuration

@EnableAutoConfiguration

@ComponentScan

public class

Application

extends

SpringBootServletInitializer {

@Override

protected

SpringApplicationBuilder configure(SpringApplicationBuilder application) {

// Customize the application or call application.sources(...) to add sources

// Since our example is itself a @Configuration class we actually don't

// need to override this method.

return

application;

}

}

Remember that whatever you put in the sources

is just a Spring

ApplicationContext

and normally anything that already works should work here. There might be some beans you can remove later and let

Spring Boot provide its own defaults for them, but it should be possible to get something working first.

Static resources can be moved to

/public

(or

/static

or

/resources

or

/META-INF/resources

) in the classpath root. Same for messages.properties

(Spring Boot detects this automatically in the root of the classpath).

Vanilla usage of Spring

DispatcherServlet

and Spring Security should require no further changes. If you have other features in your application, using other servlets or filters for instance, then you may need to add some configuration to your

Application

context, replacing those elements from the web.xml

as follows:

• A

@Bean

of type

Servlet

or

ServletRegistrationBean

installs that bean in the container as if it was a

<servlet/>

and

<servlet-mapping/>

in web.xml

.

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• A

@Bean

of type

Filter

or

FilterRegistrationBean

behaves similarly (like a

<filter/>

and

<filter-mapping/>

.

• An

ApplicationContext

in an XML file can be added to an

@Import

in your

Application

. Or simple cases where annotation configuration is heavily used already can be recreated in a few lines as

@Bean

definitions.

Once the war is working we make it executable by adding a main

method to our

Application

, e.g.

public static void

main(String[] args) {

SpringApplication.run(Application.

class

, args);

}

Applications can fall into more than one category:

• Servlet 3.0+ applications with no web.xml

.

• Applications with a web.xml

.

• Applications with a context hierarchy.

• Applications without a context hierarchy.

All of these should be amenable to translation, but each might require slightly different tricks.

Servlet 3.0+ applications might translate pretty easily if they already use the Spring Servlet 3.0+ initializer support classes. Normally all the code from an existing

WebApplicationInitializer can be moved into a

SpringBootServletInitializer

. If your existing application has more than one

ApplicationContext

(e.g. if it uses

AbstractDispatcherServletInitializer

) then you might be able to squash all your context sources into a single

SpringApplication

. The main complication you might encounter is if that doesn’t work and you need to maintain the context hierarchy.

See the entry on building a hierarchy for examples. An existing parent context that contains web-specific

features will usually need to be broken up so that all the

ServletContextAware

components are in the child context.

Applications that are not already Spring applications might be convertible to a Spring Boot application, and the guidance above might help, but your mileage may vary.

80.4 Deploying a WAR to WebLogic

To deploy a Spring Boot application to WebLogic you must ensure that your servlet initializer directly implements

WebApplicationInitializer

(even if you extend from a base class that already implements it).

A typical initializer for WebLogic would be something like this:

import

org.springframework.boot.autoconfigure.SpringBootApplication;

import

org.springframework.boot.context.web.SpringBootServletInitializer;

import

org.springframework.web.WebApplicationInitializer;

@SpringBootApplication

public class

MyApplication

extends

SpringBootServletInitializer

implements

WebApplicationInitializer {

}

If you use logback, you will also need to tell WebLogic to prefer the packaged version rather than the version that pre-installed with the server. You can do this by adding a

WEB-INF/weblogic.xml

file with the following contents:

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<?xml version="1.0" encoding="UTF-8"?>

<wls:weblogic-web-app xmlns:wls

=

"http://xmlns.oracle.com/weblogic/weblogic-web-app" xmlns:xsi

=

"http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation

=

"http://java.sun.com/xml/ns/javaee

http://java.sun.com/xml/ns/javaee/ejb-jar_3_0.xsd

http://xmlns.oracle.com/weblogic/weblogic-web-app

http://xmlns.oracle.com/weblogic/weblogic-web-app/1.4/weblogic-web-app.xsd" >

<wls:container-descriptor>

<wls:prefer-application-packages>

<wls:package-name>

org.slf4j

</wls:package-name>

</wls:prefer-application-packages>

</wls:container-descriptor>

</wls:weblogic-web-app>

80.5 Deploying a WAR in an Old (Servlet 2.5) Container

Spring Boot uses Servlet 3.0 APIs to initialize the

ServletContext

(register

Servlets

etc.) so you can’t use the same application out of the box in a Servlet 2.5 container. It is however possible to run a Spring Boot application on an older container with some special tools. If you include org.springframework.boot:spring-boot-legacy

as a dependency ( maintained separately to the core of Spring Boot and currently available at 1.0.0.RELEASE), all you should need to do is create a web.xml

and declare a context listener to create the application context and your filters and servlets.

The context listener is a special purpose one for Spring Boot, but the rest of it is normal for a Spring application in Servlet 2.5. Example:

<?xml version="1.0" encoding="UTF-8"?>

<web-app version

=

"2.5" xmlns

=

"http://java.sun.com/xml/ns/javaee" xmlns:xsi

=

"http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation

=

"http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/webapp_2_5.xsd" >

<context-param>

<param-name>

contextConfigLocation

</param-name>

<param-value>

demo.Application

</param-value>

</context-param>

<listener>

<listener-class>

org.springframework.boot.legacy.context.web.SpringBootContextLoaderListener

</ listener-class>

</listener>

<filter>

<filter-name>

metricFilter

</filter-name>

<filter-class>

org.springframework.web.filter.DelegatingFilterProxy

</filter-class>

</filter>

<filter-mapping>

<filter-name>

metricFilter

</filter-name>

<url-pattern>

/*

</url-pattern>

</filter-mapping>

<servlet>

<servlet-name>

appServlet

</servlet-name>

<servlet-class>

org.springframework.web.servlet.DispatcherServlet

</servlet-class>

<init-param>

<param-name>

contextAttribute

</param-name>

<param-value>

org.springframework.web.context.WebApplicationContext.ROOT

</param-value>

</init-param>

<load-on-startup>

1

</load-on-startup>

</servlet>

<servlet-mapping>

<servlet-name>

appServlet

</servlet-name>

<url-pattern>

/

</url-pattern>

</servlet-mapping>

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</web-app>

In this example we are using a single application context (the one created by the context listener) and attaching it to the

DispatcherServlet

using an init parameter. This is normal in a Spring Boot application (you normally only have one application context).

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Appendix A. Common application properties

Various properties can be specified inside your application.properties

/ application.yml

file or as command line switches. This section provides a list common Spring Boot properties and references to the underlying classes that consume them.

Note

Property contributions can come from additional jar files on your classpath so you should not consider this an exhaustive list. It is also perfectly legit to define your own properties.

Warning

This sample file is meant as a guide only. Do not copy/paste the entire content into your application; rather pick only the properties that you need.

# ===================================================================

# COMMON SPRING BOOT PROPERTIES

#

# This sample file is provided as a guideline. Do NOT copy it in its

# entirety to your own application. ^^^

# ===================================================================

# ----------------------------------------

# CORE PROPERTIES

# ----------------------------------------

# BANNER

banner.charset

=UTF-8

# Banner file encoding.

banner.location

=classpath:banner.txt

# Banner file location.

# LOGGING

logging.config

=

# Location of the logging configuration file. For instance `classpath:logback.xml` for

Logback

logging.exception-conversion-word

=%wEx

# Conversion word used when logging exceptions.

logging.file

=

# Log file name. For instance `myapp.log`

logging.level.*

=

# Log levels severity mapping. For instance `logging.level.org.springframework=DEBUG`

logging.path

=

# Location of the log file. For instance `/var/log`

logging.pattern.console

=

# Appender pattern for output to the console. Only supported with the default

logback setup.

logging.pattern.file

=

# Appender pattern for output to the file. Only supported with the default logback

setup.

logging.pattern.level

=

# Appender pattern for log level (default %5p). Only supported with the default

logback setup.

logging.register-shutdown-hook

=false

# Register a shutdown hook for the logging system when it is

initialized.

# AOP

spring.aop.auto

=true

# Add @EnableAspectJAutoProxy.

spring.aop.proxy-target-class

=false

# Whether subclass-based (CGLIB) proxies are to be created (true) as

opposed to standard Java interface-based proxies (false).

# IDENTITY (

ContextIdApplicationContextInitializer )

spring.application.index

=

# Application index.

spring.application.name

=

# Application name.

# ADMIN (

SpringApplicationAdminJmxAutoConfiguration )

spring.application.admin.enabled

=false

# Enable admin features for the application.

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spring.application.admin.jmx-name

=org.springframework.boot:type=Admin,name=SpringApplication

# JMX name

of the application admin MBean.

# AUTO-CONFIGURATION

spring.autoconfigure.exclude

=

# Auto-configuration classes to exclude.

# SPRING CORE

spring.beaninfo.ignore

=true

# Skip search of BeanInfo classes.

# SPRING CACHE (

CacheProperties )

spring.cache.cache-names

=

# Comma-separated list of cache names to create if supported by the underlying

cache manager.

spring.cache.ehcache.config

=

# The location of the configuration file to use to initialize EhCache.

spring.cache.guava.spec

=

# The spec to use to create caches. Check CacheBuilderSpec for more details on

the spec format.

spring.cache.hazelcast.config

=

# The location of the configuration file to use to initialize Hazelcast.

spring.cache.infinispan.config

=

# The location of the configuration file to use to initialize

Infinispan.

spring.cache.jcache.config

=

# The location of the configuration file to use to initialize the cache

manager.

spring.cache.jcache.provider

=

# Fully qualified name of the CachingProvider implementation to use to

retrieve the JSR-107 compliant cache manager. Only needed if more than one JSR-107 implementation is

available on the classpath.

spring.cache.type

=

# Cache type, auto-detected according to the environment by default.

# SPRING CONFIG (

ConfigFileApplicationListener )

spring.config.location

=

# Config file locations.

spring.config.name

=application

# Config file name.

# HAZELCAST (

HazelcastProperties )

spring.hazelcast.config

=

# The location of the configuration file to use to initialize Hazelcast.

# JMX

spring.jmx.default-domain

=

# JMX domain name.

spring.jmx.enabled

=true

# Expose management beans to the JMX domain.

spring.jmx.server

=mbeanServer

# MBeanServer bean name.

# Email (

MailProperties )

spring.mail.default-encoding

=UTF-8

# Default MimeMessage encoding.

spring.mail.host

=

# SMTP server host. For instance `smtp.example.com`

spring.mail.jndi-name

=

# Session JNDI name. When set, takes precedence to others mail settings.

spring.mail.password

=

# Login password of the SMTP server.

spring.mail.port

=

# SMTP server port.

spring.mail.properties.*

=

# Additional JavaMail session properties.

spring.mail.protocol

=smtp

# Protocol used by the SMTP server.

spring.mail.test-connection

=false

# Test that the mail server is available on startup.

spring.mail.username

=

# Login user of the SMTP server.

# APPLICATION SETTINGS (

SpringApplication )

spring.main.banner-mode

=console

# Mode used to display the banner when the application runs.

spring.main.sources

=

# Sources (class name, package name or XML resource location) to include in the

ApplicationContext.

spring.main.web-environment

=

# Run the application in a web environment (auto-detected by default).

# FILE ENCODING (

FileEncodingApplicationListener )

spring.mandatory-file-encoding

=

# Expected character encoding the application must use.

# INTERNATIONALIZATION (

MessageSourceAutoConfiguration )

spring.messages.basename

=messages

# Comma-separated list of basenames, each following the ResourceBundle

convention.

spring.messages.cache-seconds

=-1

# Loaded resource bundle files cache expiration, in seconds. When set

to -1, bundles are cached forever.

spring.messages.encoding

=UTF-8

# Message bundles encoding.

spring.messages.fallback-to-system-locale

=true

# Set whether to fall back to the system Locale if no

files for a specific Locale have been found.

# OUTPUT

spring.output.ansi.enabled

=detect

# Configure the ANSI output (can be "detect", "always", "never").

# PID FILE (

ApplicationPidFileWriter )

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spring.pid.fail-on-write-error

=

# Fail if ApplicationPidFileWriter is used but it cannot write the PID

file.

spring.pid.file

=

# Location of the PID file to write (if ApplicationPidFileWriter is used).

# PROFILES

spring.profiles.active

=

# Comma-separated list of

active profiles

.

spring.profiles.include

=

# Unconditionally activate the specified comma separated profiles.

# SENDGRID (

SendGridAutoConfiguration )

spring.sendgrid.username

=

# SendGrid account username

spring.sendgrid.password

=

# SendGrid account password

spring.sendgrid.proxy.host

=

# SendGrid proxy host

spring.sendgrid.proxy.port

=

# SendGrid proxy port

# ----------------------------------------

# WEB PROPERTIES

# ----------------------------------------

# MULTIPART (

MultipartProperties )

multipart.enabled

=true

# Enable support of multi-part uploads.

multipart.file-size-threshold

=0

# Threshold after which files will be written to disk. Values can use

the suffixed "MB" or "KB" to indicate a Megabyte or Kilobyte size.

multipart.location

=

# Intermediate location of uploaded files.

multipart.max-file-size

=1Mb

# Max file size. Values can use the suffixed "MB" or "KB" to indicate a

Megabyte or Kilobyte size.

multipart.max-request-size

=10Mb

# Max request size. Values can use the suffixed "MB" or "KB" to indicate

a Megabyte or Kilobyte size.

# EMBEDDED SERVER CONFIGURATION (

ServerProperties )

server.address

=

# Network address to which the server should bind to.

server.compression.enabled

=false

# If response compression is enabled.

server.compression.excluded-user-agents

=

# List of user-agents to exclude from compression.

server.compression.mime-types

=

# Comma-separated list of MIME types that should be compressed. For

instance `text/html,text/css,application/json`

server.compression.min-response-size

=

# Minimum response size that is required for compression to be

performed. For instance 2048

server.context-parameters.*

=

# Servlet context init parameters. For instance `server.contextparameters.a=alpha`

server.context-path

=

# Context path of the application.

server.display-name

=application

# Display name of the application.

server.error.include-stacktrace

=never

# When to include a "stacktrace" attribute.

server.error.path

=/error

# Path of the error controller.

server.error.whitelabel.enabled

=true

# Enable the default error page displayed in browsers in case of a

server error.

server.jsp-servlet.class-name

=org.apache.jasper.servlet.JspServlet

# The class name of the JSP servlet.

server.jsp-servlet.init-parameters.*

=

# Init parameters used to configure the JSP servlet

server.jsp-servlet.registered

=true

# Whether or not the JSP servlet is registered

server.port

=8080

# Server HTTP port.

server.server-header

=

# The value sent in the server response header (uses servlet container default if

empty)

server.servlet-path

=/

# Path of the main dispatcher servlet.

server.session.cookie.comment

=

# Comment for the session cookie.

server.session.cookie.domain

=

# Domain for the session cookie.

server.session.cookie.http-only

=

# "HttpOnly" flag for the session cookie.

server.session.cookie.max-age

=

# Maximum age of the session cookie in seconds.

server.session.cookie.name

=

# Session cookie name.

server.session.cookie.path

=

# Path of the session cookie.

server.session.cookie.secure

=

# "Secure" flag for the session cookie.

server.session.persistent

=false

# Persist session data between restarts.

server.session.store-dir

=

# Directory used to store session data.

server.session.timeout

=

# Session timeout in seconds.

server.session.tracking-modes

=

# Session tracking modes (one or more of the following: "cookie", "url",

"ssl").

server.ssl.ciphers

=

# Supported SSL ciphers.

server.ssl.client-auth

=

# Whether client authentication is wanted ("want") or needed ("need"). Requires

a trust store.

server.ssl.enabled

=

#

server.ssl.key-alias

=

#

server.ssl.key-password

=

#

server.ssl.key-store

=

#

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server.ssl.key-store-password

=

#

server.ssl.key-store-provider

=

#

server.ssl.key-store-type

=

#

server.ssl.protocol

=

#

server.ssl.trust-store

=

#

server.ssl.trust-store-password

=

#

server.ssl.trust-store-provider

=

#

server.ssl.trust-store-type

=

#

server.tomcat.accesslog.directory

=logs

# Directory in which log files are created. Can be relative to

the tomcat base dir or absolute.

server.tomcat.accesslog.enabled

=false

# Enable access log.

server.tomcat.accesslog.pattern

=common

# Format pattern for access logs.

server.tomcat.accesslog.prefix

=access_log

# Log file name prefix.

server.tomcat.accesslog.suffix

=.log

# Log file name suffix.

server.tomcat.background-processor-delay

=30

# Delay in seconds between the invocation of

backgroundProcess methods.

server.tomcat.basedir

=

# Tomcat base directory. If not specified a temporary directory will be used.

server.tomcat.internal-proxies

=10\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}|\\

192\\.168\\.\\d{1,3}\\.\\d{1,3}|\\

169\\.254\\.\\d{1,3}\\.\\d{1,3}|\\

127\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}|\\

172\\.1[6-9]{1}\\.\\d{1,3}\\.\\d{1,3}|\\

172\\.2[0-9]{1}\\.\\d{1,3}\\.\\d{1,3}|\\

172\\.3[0-1]{1}\\.\\d{1,3}\\.\\d{1,3}

# regular expression matching trusted IP addresses.

server.tomcat.max-http-header-size

=0

# Maximum size in bytes of the HTTP message header.

server.tomcat.max-threads

=0

# Maximum amount of worker threads.

server.tomcat.port-header

=X-Forwarded-Port

# Name of the HTTP header used to override the original port

value.

server.tomcat.protocol-header

=

# Header that holds the incoming protocol, usually named "X-Forwarded-

Proto".

server.tomcat.protocol-header-https-value

=https

# Value of the protocol header that indicates that the

incoming request uses SSL.

server.tomcat.remote-ip-header

=

# Name of the http header from which the remote ip is extracted. For

instance `X-FORWARDED-FOR`

server.tomcat.uri-encoding

=UTF-8

# Character encoding to use to decode the URI.

server.undertow.accesslog.dir

=

# Undertow access log directory.

server.undertow.accesslog.enabled

=false

# Enable access log.

server.undertow.accesslog.pattern

=common

# Format pattern for access logs.

server.undertow.buffer-size

=

# Size of each buffer in bytes.

server.undertow.buffers-per-region

=

# Number of buffer per region.

server.undertow.direct-buffers

=

# Allocate buffers outside the Java heap.

server.undertow.io-threads

=

# Number of I/O threads to create for the worker.

server.undertow.worker-threads

=

# Number of worker threads.

server.use-forward-headers

=

# If X-Forwarded-* headers should be applied to the HttpRequest.

# FREEMARKER (

FreeMarkerAutoConfiguration )

spring.freemarker.allow-request-override

=false

# Set whether HttpServletRequest attributes are allowed

to override (hide) controller generated model attributes of the same name.

spring.freemarker.allow-session-override

=false

# Set whether HttpSession attributes are allowed to

override (hide) controller generated model attributes of the same name.

spring.freemarker.cache

=false

# Enable template caching.

spring.freemarker.charset

=UTF-8

# Template encoding.

spring.freemarker.check-template-location

=true

# Check that the templates location exists.

spring.freemarker.content-type

=text/html

# Content-Type value.

spring.freemarker.enabled

=true

# Enable MVC view resolution for this technology.

spring.freemarker.expose-request-attributes

=false

# Set whether all request attributes should be added

to the model prior to merging with the template.

spring.freemarker.expose-session-attributes

=false

# Set whether all HttpSession attributes should be

added to the model prior to merging with the template.

spring.freemarker.expose-spring-macro-helpers

=true

# Set whether to expose a RequestContext for use by

Spring's macro library, under the name "springMacroRequestContext".

spring.freemarker.prefer-file-system-access

=true

# Prefer file system access for template loading. File

system access enables hot detection of template changes.

spring.freemarker.prefix

=

# Prefix that gets prepended to view names when building a URL.

spring.freemarker.request-context-attribute

=

# Name of the RequestContext attribute for all views.

spring.freemarker.settings.*

=

# Well-known FreeMarker keys which will be passed to FreeMarker's

Configuration.

spring.freemarker.suffix

=

# Suffix that gets appended to view names when building a URL.

spring.freemarker.template-loader-path

=classpath:/templates/

# Comma-separated list of template paths.

spring.freemarker.view-names

=

# White list of view names that can be resolved.

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# GROOVY TEMPLATES (

GroovyTemplateAutoConfiguration )

spring.groovy.template.allow-request-override

=false

# Set whether HttpServletRequest attributes are

allowed to override (hide) controller generated model attributes of the same name.

spring.groovy.template.allow-session-override

=false

# Set whether HttpSession attributes are allowed to

override (hide) controller generated model attributes of the same name.

spring.groovy.template.cache

=

# Enable template caching.

spring.groovy.template.charset

=UTF-8

# Template encoding.

spring.groovy.template.check-template-location

=true

# Check that the templates location exists.

spring.groovy.template.configuration.*

=

# See GroovyMarkupConfigurer

spring.groovy.template.content-type

=test/html

# Content-Type value.

spring.groovy.template.enabled

=true

# Enable MVC view resolution for this technology.

spring.groovy.template.expose-request-attributes

=false

# Set whether all request attributes should be

added to the model prior to merging with the template.

spring.groovy.template.expose-session-attributes

=false

# Set whether all HttpSession attributes should

be added to the model prior to merging with the template.

spring.groovy.template.expose-spring-macro-helpers

=true

# Set whether to expose a RequestContext for use

by Spring's macro library, under the name "springMacroRequestContext".

spring.groovy.template.prefix

=

# Prefix that gets prepended to view names when building a URL.

spring.groovy.template.request-context-attribute

=

# Name of the RequestContext attribute for all views.

spring.groovy.template.resource-loader-path

=classpath:/templates/

# Template path.

spring.groovy.template.suffix

=.tpl

# Suffix that gets appended to view names when building a URL.

spring.groovy.template.view-names

=

# White list of view names that can be resolved.

# SPRING HATEOAS (

HateoasProperties )

spring.hateoas.use-hal-as-default-json-media-type

=true

# Specify if application/hal+json responses

should be sent to requests that accept application/json.

# HTTP message conversion

spring.http.converters.preferred-json-mapper

=jackson

# Preferred JSON mapper to use for HTTP message

conversion. Set to "gson" to force the use of Gson when both it and Jackson are on the classpath.

# HTTP encoding (

HttpEncodingProperties )

spring.http.encoding.charset

=UTF-8

# Charset of HTTP requests and responses. Added to the "Content-Type"

header if not set explicitly.

spring.http.encoding.enabled

=true

# Enable http encoding support.

spring.http.encoding.force

=true

# Force the encoding to the configured charset on HTTP requests and

responses.

# JACKSON (

JacksonProperties )

spring.jackson.date-format

=

# Date format string or a fully-qualified date format class name. For

instance `yyyy-MM-dd HH:mm:ss`.

spring.jackson.deserialization.*

=

# Jackson on/off features that affect the way Java objects are

deserialized.

spring.jackson.generator.*

=

# Jackson on/off features for generators.

spring.jackson.joda-date-time-format

=

# Joda date time format string. If not configured, "date-format"

will be used as a fallback if it is configured with a format string.

spring.jackson.locale

=

# Locale used for formatting.

spring.jackson.mapper.*

=

# Jackson general purpose on/off features.

spring.jackson.parser.*

=

# Jackson on/off features for parsers.

spring.jackson.property-naming-strategy

=

# One of the constants on Jackson's PropertyNamingStrategy. Can

also be a fully-qualified class name of a PropertyNamingStrategy subclass.

spring.jackson.serialization.*

=

# Jackson on/off features that affect the way Java objects are

serialized.

spring.jackson.serialization-inclusion

=

# Controls the inclusion of properties during serialization.

Configured with one of the values in Jackson's JsonInclude.Include enumeration.

spring.jackson.time-zone

=

# Time zone used when formatting dates. For instance `America/Los_Angeles`

# JERSEY (

JerseyProperties )

spring.jersey.application-path

=

# Path that serves as the base URI for the application. Overrides the

value of "@ApplicationPath" if specified.

spring.jersey.filter.order

=0

# Jersey filter chain order.

spring.jersey.init.*

=

# Init parameters to pass to Jersey via the servlet or filter.

spring.jersey.type

=servlet

# Jersey integration type. Can be either "servlet" or "filter".

# SPRING MOBILE DEVICE VIEWS (

DeviceDelegatingViewResolverAutoConfiguration )

spring.mobile.devicedelegatingviewresolver.enable-fallback

=false

# Enable support for fallback

resolution.

spring.mobile.devicedelegatingviewresolver.enabled

=false

# Enable device view resolver.

spring.mobile.devicedelegatingviewresolver.mobile-prefix

=mobile/

# Prefix that gets prepended to view

names for mobile devices.

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spring.mobile.devicedelegatingviewresolver.mobile-suffix

=

# Suffix that gets appended to view names for

mobile devices.

spring.mobile.devicedelegatingviewresolver.normal-prefix

=

# Prefix that gets prepended to view names for

normal devices.

spring.mobile.devicedelegatingviewresolver.normal-suffix

=

# Suffix that gets appended to view names for

normal devices.

spring.mobile.devicedelegatingviewresolver.tablet-prefix

=tablet/

# Prefix that gets prepended to view

names for tablet devices.

spring.mobile.devicedelegatingviewresolver.tablet-suffix

=

# Suffix that gets appended to view names for

tablet devices.

# SPRING MOBILE SITE PREFERENCE (

SitePreferenceAutoConfiguration )

spring.mobile.sitepreference.enabled

=true

# Enable SitePreferenceHandler.

# MUSTACHE TEMPLATES (

MustacheAutoConfiguration )

spring.mustache.cache

=false

# Enable template caching.

spring.mustache.charset

=UTF-8

# Template encoding.

spring.mustache.check-template-location

=true

# Check that the templates location exists.

spring.mustache.content-type

=text/html

# Content-Type value.

spring.mustache.enabled

=true

# Enable MVC view resolution for this technology.

spring.mustache.prefix

=classpath:/templates/

# Prefix to apply to template names.

spring.mustache.suffix

=.html

# Suffix to apply to template names.

spring.mustache.view-names

=

# White list of view names that can be resolved.

# SPRING MVC (

WebMvcProperties )

spring.mvc.async.request-timeout

=

# Amount of time (in milliseconds) before asynchronous request

handling times out.

spring.mvc.date-format

=

# Date format to use. For instance `dd/MM/yyyy`.

spring.mvc.dispatch-trace-request

=false

# Dispatch TRACE requests to the FrameworkServlet doService

method.

spring.mvc.dispatch-options-request

=false

# Dispatch OPTIONS requests to the FrameworkServlet doService

method.

spring.mvc.favicon.enabled

=true

# Enable resolution of favicon.ico.

spring.mvc.ignore-default-model-on-redirect

=true

# If the content of the "default" model should be

ignored during redirect scenarios.

spring.mvc.locale

=

# Locale to use.

spring.mvc.media-types.*

=

# Maps file extensions to media types for content negotiation.

spring.mvc.message-codes-resolver-format

=

# Formatting strategy for message codes. For instance

`PREFIX_ERROR_CODE`.

spring.mvc.static-path-pattern

=/**

# Path pattern used for static resources.

spring.mvc.throw-exception-if-no-handler-found

=false

# If a "NoHandlerFoundException" should be thrown

if no Handler was found to process a request.

spring.mvc.view.prefix

=

# Spring MVC view prefix.

spring.mvc.view.suffix

=

# Spring MVC view suffix.

# SPRING RESOURCES HANDLING (

ResourceProperties )

spring.resources.add-mappings

=true

# Enable default resource handling.

spring.resources.cache-period

=

# Cache period for the resources served by the resource handler, in

seconds.

spring.resources.chain.cache

=true

# Enable caching in the Resource chain.

spring.resources.chain.enabled

=

# Enable the Spring Resource Handling chain. Disabled by default unless

at least one strategy has been enabled.

spring.resources.chain.html-application-cache

=false

# Enable HTML5 application cache manifest rewriting.

spring.resources.chain.strategy.content.enabled

=false

# Enable the content Version Strategy.

spring.resources.chain.strategy.content.paths

=/**

# Comma-separated list of patterns to apply to the

Version Strategy.

spring.resources.chain.strategy.fixed.enabled

=false

# Enable the fixed Version Strategy.

spring.resources.chain.strategy.fixed.paths

=

# Comma-separated list of patterns to apply to the Version

Strategy.

spring.resources.chain.strategy.fixed.version

=

# Version string to use for the Version Strategy.

spring.resources.static-locations

=classpath:/META-INF/resources/,classpath:/resources/,classpath:/ static/,classpath:/public/

# Locations of static resources.

# SPRING SOCIAL (

SocialWebAutoConfiguration )

spring.social.auto-connection-views

=false

# Enable the connection status view for supported providers.

# SPRING SOCIAL FACEBOOK (

FacebookAutoConfiguration )

spring.social.facebook.app-id

=

# your application's Facebook App ID

spring.social.facebook.app-secret

=

# your application's Facebook App Secret

# SPRING SOCIAL LINKEDIN (

LinkedInAutoConfiguration )

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spring.social.linkedin.app-id

=

# your application's LinkedIn App ID

spring.social.linkedin.app-secret

=

# your application's LinkedIn App Secret

# SPRING SOCIAL TWITTER (

TwitterAutoConfiguration )

spring.social.twitter.app-id

=

# your application's Twitter App ID

spring.social.twitter.app-secret

=

# your application's Twitter App Secret

# THYMELEAF (

ThymeleafAutoConfiguration )

spring.thymeleaf.cache

=true

# Enable template caching.

spring.thymeleaf.check-template-location

=true

# Check that the templates location exists.

spring.thymeleaf.content-type

=text/html

# Content-Type value.

spring.thymeleaf.enabled

=true

# Enable MVC Thymeleaf view resolution.

spring.thymeleaf.encoding

=UTF-8

# Template encoding.

spring.thymeleaf.excluded-view-names

=

# Comma-separated list of view names that should be excluded from

resolution.

spring.thymeleaf.mode

=HTML5

# Template mode to be applied to templates. See also

StandardTemplateModeHandlers.

spring.thymeleaf.prefix

=classpath:/templates/

# Prefix that gets prepended to view names when building a

URL.

spring.thymeleaf.suffix

=.html

# Suffix that gets appended to view names when building a URL.

spring.thymeleaf.template-resolver-order

=

# Order of the template resolver in the chain.

spring.thymeleaf.view-names

=

# Comma-separated list of view names that can be resolved.

# VELOCITY TEMPLATES (

VelocityAutoConfiguration )

spring.velocity.allow-request-override

=false

# Set whether HttpServletRequest attributes are allowed to

override (hide) controller generated model attributes of the same name.

spring.velocity.allow-session-override

=false

# Set whether HttpSession attributes are allowed to

override (hide) controller generated model attributes of the same name.

spring.velocity.cache

=

# Enable template caching.

spring.velocity.charset

=UTF-8

# Template encoding.

spring.velocity.check-template-location

=true

# Check that the templates location exists.

spring.velocity.content-type

=text/html

# Content-Type value.

spring.velocity.date-tool-attribute

=

# Name of the DateTool helper object to expose in the Velocity

context of the view.

spring.velocity.enabled

=true

# Enable MVC view resolution for this technology.

spring.velocity.expose-request-attributes

=false

# Set whether all request attributes should be added to

the model prior to merging with the template.

spring.velocity.expose-session-attributes

=false

# Set whether all HttpSession attributes should be added

to the model prior to merging with the template.

spring.velocity.expose-spring-macro-helpers

=true

# Set whether to expose a RequestContext for use by

Spring's macro library, under the name "springMacroRequestContext".

spring.velocity.number-tool-attribute

=

# Name of the NumberTool helper object to expose in the Velocity

context of the view.

spring.velocity.prefer-file-system-access

=true

# Prefer file system access for template loading. File

system access enables hot detection of template changes.

spring.velocity.prefix

=

# Prefix that gets prepended to view names when building a URL.

spring.velocity.properties.*

=

# Additional velocity properties.

spring.velocity.request-context-attribute

=

# Name of the RequestContext attribute for all views.

spring.velocity.resource-loader-path

=classpath:/templates/

# Template path.

spring.velocity.suffix

=.vm

# Suffix that gets appended to view names when building a URL.

spring.velocity.toolbox-config-location

=

# Velocity Toolbox config location. For instance `/WEB-INF/ toolbox.xml`

spring.velocity.view-names

=

# White list of view names that can be resolved.

# ----------------------------------------

# SECURITY PROPERTIES

# ----------------------------------------

# SECURITY (

SecurityProperties )

security.basic.authorize-mode

=role

# Security authorize mode to apply.

security.basic.enabled

=true

# Enable basic authentication.

security.basic.path

=/**

# Comma-separated list of paths to secure.

security.basic.realm

=Spring

# HTTP basic realm name.

security.enable-csrf

=false

# Enable Cross Site Request Forgery support.

security.filter-order

=0

# Security filter chain order.

security.filter-dispatcher-types

=ASYNC, FORWARD, INCLUDE, REQUEST

# Security filter chain dispatcher

types.

security.headers.cache

=true

# Enable cache control HTTP headers.

security.headers.content-type

=true

# Enable "X-Content-Type-Options" header.

security.headers.frame

=true

# Enable "X-Frame-Options" header.

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security.headers.hsts

=

# HTTP Strict Transport Security (HSTS) mode (none, domain, all).

security.headers.xss

=true

# Enable cross site scripting (XSS) protection.

security.ignored

=

# Comma-separated list of paths to exclude from the default secured paths.

security.require-ssl

=false

# Enable secure channel for all requests.

security.sessions

=stateless

# Session creation policy (always, never, if_required, stateless).

security.user.name

=user

# Default user name.

security.user.password

=

# Password for the default user name. A random password is logged on startup by

default.

security.user.role

=USER

# Granted roles for the default user name.

# SECURITY OAUTH2 CLIENT (

OAuth2ClientProperties

security.oauth2.client.client-id

=

# OAuth2 client id.

security.oauth2.client.client-secret

=

# OAuth2 client secret. A random secret is generated by default

# SECURITY OAUTH2 RESOURCES (

ResourceServerProperties

security.oauth2.resource.id

=

# Identifier of the resource.

security.oauth2.resource.jwt.key-uri

=

# The URI of the JWT token. Can be set if the value is not

available and the key is public.

security.oauth2.resource.jwt.key-value

=

# The verification key of the JWT token. Can either be a

symmetric secret or PEM-encoded RSA public key.

security.oauth2.resource.prefer-token-info

=true

# Use the token info, can be set to false to use the

user info.

security.oauth2.resource.service-id

=resource

#

security.oauth2.resource.token-info-uri

=

# URI of the token decoding endpoint.

security.oauth2.resource.token-type

=

# The token type to send when using the userInfoUri.

security.oauth2.resource.user-info-uri

=

# URI of the user endpoint.

# SECURITY OAUTH2 SSO (

OAuth2SsoProperties

security.oauth2.sso.filter-order

=

# Filter order to apply if not providing an explicit

WebSecurityConfigurerAdapter

security.oauth2.sso.login-path

=/login

# Path to the login page, i.e. the one that triggers the redirect

to the OAuth2 Authorization Server

# ----------------------------------------

# DATA PROPERTIES

# ----------------------------------------

# FLYWAY (

FlywayProperties )

flyway.baseline-description

=

#

flyway.baseline-version

=1

# version to start migration

flyway.baseline-on-migrate

=

#

flyway.check-location

=false

# Check that migration scripts location exists.

flyway.clean-on-validation-error

=

#

flyway.enabled

=true

# Enable flyway.

flyway.encoding

=

#

flyway.ignore-failed-future-migration

=

#

flyway.init-sqls

=

# SQL statements to execute to initialize a connection immediately after obtaining it.

flyway.locations

=classpath:db/migration

# locations of migrations scripts

flyway.out-of-order

=

#

flyway.password

=

# JDBC password if you want Flyway to create its own DataSource

flyway.placeholder-prefix

=

#

flyway.placeholder-replacement

=

#

flyway.placeholder-suffix

=

#

flyway.placeholders.*

=

#

flyway.schemas

=

# schemas to update

flyway.sql-migration-prefix

=V

#

flyway.sql-migration-separator

=

#

flyway.sql-migration-suffix

=.sql

#

flyway.table

=

#

flyway.url

=

# JDBC url of the database to migrate. If not set, the primary configured data source is

used.

flyway.user

=

# Login user of the database to migrate.

flyway.validate-on-migrate

=

#

# LIQUIBASE (

LiquibaseProperties )

liquibase.change-log

=classpath:/db/changelog/db.changelog-master.yaml

# Change log configuration path.

liquibase.check-change-log-location

=true

# Check the change log location exists.

liquibase.contexts

=

# Comma-separated list of runtime contexts to use.

liquibase.default-schema

=

# Default database schema.

liquibase.drop-first

=false

# Drop the database schema first.

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liquibase.enabled

=true

# Enable liquibase support.

liquibase.labels

=

# Comma-separated list of runtime labels to use.

liquibase.parameters.*

=

# Change log parameters.

liquibase.password

=

# Login password of the database to migrate.

liquibase.url

=

# JDBC url of the database to migrate. If not set, the primary configured data source is

used.

liquibase.user

=

# Login user of the database to migrate.

# DAO (

PersistenceExceptionTranslationAutoConfiguration )

spring.dao.exceptiontranslation.enabled

=true

# Enable the PersistenceExceptionTranslationPostProcessor.

# CASSANDRA (

CassandraProperties )

spring.data.cassandra.cluster-name

=

# Name of the Cassandra cluster.

spring.data.cassandra.compression

=

# Compression supported by the Cassandra binary protocol.

spring.data.cassandra.connect-timeout-millis

=

# Socket option: connection time out.

spring.data.cassandra.consistency-level

=

# Queries consistency level.

spring.data.cassandra.contact-points

=localhost

# Comma-separated list of cluster node addresses.

spring.data.cassandra.fetch-size

=

# Queries default fetch size.

spring.data.cassandra.keyspace-name

=

# Keyspace name to use.

spring.data.cassandra.load-balancing-policy

=

# Class name of the load balancing policy.

spring.data.cassandra.port

=

# Port of the Cassandra server.

spring.data.cassandra.password

=

# Login password of the server.

spring.data.cassandra.read-timeout-millis

=

# Socket option: read time out.

spring.data.cassandra.reconnection-policy

=

# Reconnection policy class.

spring.data.cassandra.retry-policy

=

# Class name of the retry policy.

spring.data.cassandra.serial-consistency-level

=

# Queries serial consistency level.

spring.data.cassandra.ssl

=false

# Enable SSL support.

spring.data.cassandra.username

=

# Login user of the server.

# ELASTICSEARCH (

ElasticsearchProperties )

spring.data.elasticsearch.cluster-name

=elasticsearch

# Elasticsearch cluster name.

spring.data.elasticsearch.cluster-nodes

=

# Comma-separated list of cluster node addresses. If not

specified, starts a client node.

spring.data.elasticsearch.properties.*

=

# Additional properties used to configure the client.

spring.data.elasticsearch.repositories.enabled

=true

# Enable Elasticsearch repositories.

# MONGODB (

MongoProperties )

spring.data.mongodb.authentication-database

=

# Authentication database name.

spring.data.mongodb.database

=test

# Database name.

spring.data.mongodb.field-naming-strategy

=

# Fully qualified name of the FieldNamingStrategy to use.

spring.data.mongodb.grid-fs-database

=

# GridFS database name.

spring.data.mongodb.host

=localhost

# Mongo server host.

spring.data.mongodb.password

=

# Login password of the mongo server.

spring.data.mongodb.port

=27017

# Mongo server port.

spring.data.mongodb.repositories.enabled

=true

# Enable Mongo repositories.

spring.data.mongodb.uri

=mongodb://localhost/test

# Mongo database URI. When set, host and port are

ignored.

spring.data.mongodb.username

=

# Login user of the mongo server.

# DATA REST (

RepositoryRestProperties )

spring.data.rest.base-path

=

# Base path to be used by Spring Data REST to expose repository resources.

spring.data.rest.default-page-size

=

# Default size of pages.

spring.data.rest.enable-enum-translation

=

# Enable enum value translation via the Spring Data REST

default resource bundle.

spring.data.rest.limit-param-name

=

# Name of the URL query string parameter that indicates how many

results to return at once.

spring.data.rest.max-page-size

=

# Maximum size of pages.

spring.data.rest.page-param-name

=

# Name of the URL query string parameter that indicates what page to

return.

spring.data.rest.return-body-on-create

=

# Return a response body after creating an entity.

spring.data.rest.return-body-on-update

=

# Return a response body after updating an entity.

spring.data.rest.sort-param-name

=

# Name of the URL query string parameter that indicates what direction

to sort results.

# SOLR (

SolrProperties )

spring.data.solr.host

=http://127.0.0.1:8983/solr

# Solr host. Ignored if "zk-host" is set.

spring.data.solr.repositories.enabled

=true

# Enable Solr repositories.

spring.data.solr.zk-host

=

# ZooKeeper host address in the form HOST:PORT.

# DATASOURCE (

DataSourceAutoConfiguration & DataSourceProperties )

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spring.datasource.continue-on-error

=false

# Do not stop if an error occurs while initializing the

database.

spring.datasource.data

=

# Data (DML) script resource reference.

spring.datasource.driver-class-name

=

# Fully qualified name of the JDBC driver. Auto-detected based on

the URL by default.

spring.datasource.initialize

=true

# Populate the database using 'data.sql'.

spring.datasource.jmx-enabled

=false

# Enable JMX support (if provided by the underlying pool).

spring.datasource.jndi-name

=

# JNDI location of the datasource. Class, url, username & password are

ignored when set.

spring.datasource.max-active

=

# For instance 100

spring.datasource.max-idle

=

# For instance 8

spring.datasource.max-wait

=

spring.datasource.min-evictable-idle-time-millis

=

spring.datasource.min-idle

=8

spring.datasource.name

=testdb

# Name of the datasource.

spring.datasource.password

=

# Login password of the database.

spring.datasource.platform

=all

# Platform to use in the schema resource (schema-${platform}.sql).

spring.datasource.schema

=

# Schema (DDL) script resource reference.

spring.datasource.separator

=;

# Statement separator in SQL initialization scripts.

spring.datasource.sql-script-encoding

=

# SQL scripts encoding.

spring.datasource.test-on-borrow

=

# For instance `false`

spring.datasource.test-on-return

=

# For instance `false`

spring.datasource.test-while-idle

=

#

spring.datasource.time-between-eviction-runs-millis

= 1

spring.datasource.type

=

# Fully qualified name of the connection pool implementation to use. By default,

it is auto-detected from the classpath.

spring.datasource.url

=

# JDBC url of the database.

spring.datasource.username

=

spring.datasource.validation-query

=

# H2 Web Console (

H2ConsoleProperties )

spring.h2.console.enabled

=false

# Enable the console.

spring.h2.console.path

=/h2-console

# Path at which the console will be available.

# JOOQ (

JooqAutoConfiguration )

spring.jooq.sql-dialect

=

# SQLDialect JOOQ used when communicating with the configured datasource. For

instance `POSTGRES`

# JPA (

JpaBaseConfiguration , HibernateJpaAutoConfiguration )

spring.data.jpa.repositories.enabled

=true

# Enable JPA repositories.

spring.jpa.database

=

# Target database to operate on, auto-detected by default. Can be alternatively set

using the "databasePlatform" property.

spring.jpa.database-platform

=

# Name of the target database to operate on, auto-detected by default. Can

be alternatively set using the "Database" enum.

spring.jpa.generate-ddl

=false

# Initialize the schema on startup.

spring.jpa.hibernate.ddl-auto

=

# DDL mode. This is actually a shortcut for the "hibernate.hbm2ddl.auto"

property. Default to "create-drop" when using an embedded database, "none" otherwise.

spring.jpa.hibernate.naming-strategy

=

# Naming strategy fully qualified name.

spring.jpa.open-in-view

=true

# Register OpenEntityManagerInViewInterceptor. Binds a JPA EntityManager to

the thread for the entire processing of the request.

spring.jpa.properties.*

=

# Additional native properties to set on the JPA provider.

spring.jpa.show-sql

=false

# Enable logging of SQL statements.

# JTA (

JtaAutoConfiguration )

spring.jta.*

=

# technology specific configuration

spring.jta.log-dir

=

# Transaction logs directory.

# ATOMIKOS

spring.jta.atomikos.connectionfactory.borrow-connection-timeout

=30

# Timeout, in seconds, for borrowing

connections from the pool.

spring.jta.atomikos.connectionfactory.ignore-session-transacted-flag

=true

# Whether or not to ignore the

transacted flag when creating session.

spring.jta.atomikos.connectionfactory.local-transaction-mode

=false

# Whether or not local transactions

are desired.

spring.jta.atomikos.connectionfactory.maintenance-interval

=60

# The time, in seconds, between runs of

the pool's maintenance thread.

spring.jta.atomikos.connectionfactory.max-idle-time

=60

# The time, in seconds, after which connections

are cleaned up from the pool.

spring.jta.atomikos.connectionfactory.max-lifetime

=0

# The time, in seconds, that a connection can be

pooled for before being destroyed. 0 denotes no limit.

spring.jta.atomikos.connectionfactory.max-pool-size

=1

# The maximum size of the pool.

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spring.jta.atomikos.connectionfactory.min-pool-size

=1

# The minimum size of the pool.

spring.jta.atomikos.connectionfactory.reap-timeout

=0

# The reap timeout, in seconds, for borrowed

connections. 0 denotes no limit.

spring.jta.atomikos.connectionfactory.unique-resource-name

=jmsConnectionFactory

# The unique name used

to identify the resource during recovery.

spring.jta.atomikos.datasource.borrow-connection-timeout

=30

# Timeout, in seconds, for borrowing

connections from the pool.

spring.jta.atomikos.datasource.default-isolation-level

=

# Default isolation level of connections

provided by the pool.

spring.jta.atomikos.datasource.login-timeout

=

# Timeout, in seconds, for establishing a database

connection.

spring.jta.atomikos.datasource.maintenance-interval

=60

# The time, in seconds, between runs of the

pool's maintenance thread.

spring.jta.atomikos.datasource.max-idle-time

=60

# The time, in seconds, after which connections are

cleaned up from the pool.

spring.jta.atomikos.datasource.max-lifetime

=0

# The time, in seconds, that a connection can be pooled

for before being destroyed. 0 denotes no limit.

spring.jta.atomikos.datasource.max-pool-size

=1

# The maximum size of the pool.

spring.jta.atomikos.datasource.min-pool-size

=1

# The minimum size of the pool.

spring.jta.atomikos.datasource.reap-timeout

=0

# The reap timeout, in seconds, for borrowed connections.

0 denotes no limit.

spring.jta.atomikos.datasource.test-query

=

# SQL query or statement used to validate a connection before

returning it.

spring.jta.atomikos.datasource.unique-resource-name

=dataSource

# The unique name used to identify the

resource during recovery.

# BITRONIX

spring.jta.bitronix.connectionfactory.acquire-increment

=1

# Number of connections to create when growing

the pool.

spring.jta.bitronix.connectionfactory.acquisition-interval

=1

# Time, in seconds, to wait before trying

to acquire a connection again after an invalid connection was acquired.

spring.jta.bitronix.connectionfactory.acquisition-timeout

=30

# Timeout, in seconds, for acquiring

connections from the pool.

spring.jta.bitronix.connectionfactory.allow-local-transactions

=true

# Whether or not the transaction

manager should allow mixing XA and non-XA transactions.

spring.jta.bitronix.connectionfactory.apply-transaction-timeout

=false

# Whether or not the transaction

timeout should be set on the XAResource when it is enlisted.

spring.jta.bitronix.connectionfactory.automatic-enlisting-enabled

=true

# Whether or not resources should

be enlisted and delisted automatically.

spring.jta.bitronix.connectionfactory.cache-producers-consumers

=true

# Whether or not produces and

consumers should be cached.

spring.jta.bitronix.connectionfactory.defer-connection-release

=true

# Whether or not the provider can

run many transactions on the same connection and supports transaction interleaving.

spring.jta.bitronix.connectionfactory.ignore-recovery-failures

=false

# Whether or not recovery failures

should be ignored.

spring.jta.bitronix.connectionfactory.max-idle-time

=60

# The time, in seconds, after which connections

are cleaned up from the pool.

spring.jta.bitronix.connectionfactory.max-pool-size

=10

# The maximum size of the pool. 0 denotes no

limit.

spring.jta.bitronix.connectionfactory.min-pool-size

=0

# The minimum size of the pool.

spring.jta.bitronix.connectionfactory.password

=

# The password to use to connect to the JMS provider.

spring.jta.bitronix.connectionfactory.share-transaction-connections

=false

# Whether or not connections

in the ACCESSIBLE state can be shared within the context of a transaction.

spring.jta.bitronix.connectionfactory.test-connections

=true

# Whether or not connections should be

tested when acquired from the pool.

spring.jta.bitronix.connectionfactory.two-pc-ordering-position

=1

# The position that this

resource should take during two-phase commit (always first is Integer.MIN_VALUE, always last is

Integer.MAX_VALUE).

spring.jta.bitronix.connectionfactory.unique-name

=jmsConnectionFactory

# The unique name used to

identify the resource during recovery.

spring.jta.bitronix.connectionfactory.use-tm-join

=true Whether or not TMJOIN should be used when

starting XAResources.

spring.jta.bitronix.connectionfactory.user

=

# The user to use to connect to the JMS provider.

spring.jta.bitronix.datasource.acquire-increment

=1

# Number of connections to create when growing the

pool.

spring.jta.bitronix.datasource.acquisition-interval

=1

# Time, in seconds, to wait before trying to

acquire a connection again after an invalid connection was acquired.

spring.jta.bitronix.datasource.acquisition-timeout

=30

# Timeout, in seconds, for acquiring connections

from the pool.

spring.jta.bitronix.datasource.allow-local-transactions

=true

# Whether or not the transaction manager

should allow mixing XA and non-XA transactions.

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spring.jta.bitronix.datasource.apply-transaction-timeout

=false

# Whether or not the transaction timeout

should be set on the XAResource when it is enlisted.

spring.jta.bitronix.datasource.automatic-enlisting-enabled

=true

# Whether or not resources should be

enlisted and delisted automatically.

spring.jta.bitronix.datasource.cursor-holdability

=

# The default cursor holdability for connections.

spring.jta.bitronix.datasource.defer-connection-release

=true

# Whether or not the database can run many

transactions on the same connection and supports transaction interleaving.

spring.jta.bitronix.datasource.enable-jdbc4-connection-test

=

# Whether or not Connection.isValid() is

called when acquiring a connection from the pool.

spring.jta.bitronix.datasource.ignore-recovery-failures

=false

# Whether or not recovery failures should

be ignored.

spring.jta.bitronix.datasource.isolation-level

=

# The default isolation level for connections.

spring.jta.bitronix.datasource.local-auto-commit

=

# The default auto-commit mode for local transactions.

spring.jta.bitronix.datasource.login-timeout

=

# Timeout, in seconds, for establishing a database

connection.

spring.jta.bitronix.datasource.max-idle-time

=60

# The time, in seconds, after which connections are

cleaned up from the pool.

spring.jta.bitronix.datasource.max-pool-size

=10

# The maximum size of the pool. 0 denotes no limit.

spring.jta.bitronix.datasource.min-pool-size

=0

# The minimum size of the pool.

spring.jta.bitronix.datasource.prepared-statement-cache-size

=0

# The target size of the prepared

statement cache. 0 disables the cache.

spring.jta.bitronix.datasource.share-transaction-connections

=false

# Whether or not connections in the

ACCESSIBLE state can be shared within the context of a transaction.

spring.jta.bitronix.datasource.test-query

=

# SQL query or statement used to validate a connection before

returning it.

spring.jta.bitronix.datasource.two-pc-ordering-position

=1

# The position that this resource should take

during two-phase commit (always first is Integer.MIN_VALUE, always last is Integer.MAX_VALUE).

spring.jta.bitronix.datasource.unique-name

=dataSource

# The unique name used to identify the resource

during recovery.

spring.jta.bitronix.datasource.use-tm-join

=true Whether or not TMJOIN should be used when starting

XAResources.

# EMBEDDED MONGODB (

EmbeddedMongoProperties )

spring.mongodb.embedded.features

=SYNC_DELAY

# Comma-separated list of features to enable.

spring.mongodb.embedded.version

=2.6.10

# Version of Mongo to use.

# REDIS (

RedisProperties )

spring.redis.database

=0

# Database index used by the connection factory.

spring.redis.host

=localhost

# Redis server host.

spring.redis.password

=

# Login password of the redis server.

spring.redis.pool.max-active

=8

# Max number of connections that can be allocated by the pool at a given

time. Use a negative value for no limit.

spring.redis.pool.max-idle

=8

# Max number of "idle" connections in the pool. Use a negative value to

indicate an unlimited number of idle connections.

spring.redis.pool.max-wait

=-1

# Maximum amount of time (in milliseconds) a connection allocation

should block before throwing an exception when the pool is exhausted. Use a negative value to block

indefinitely.

spring.redis.pool.min-idle

=0

# Target for the minimum number of idle connections to maintain in the

pool. This setting only has an effect if it is positive.

spring.redis.port

=6379

# Redis server port.

spring.redis.sentinel.master

=

# Name of Redis server.

spring.redis.sentinel.nodes

=

# Comma-separated list of host:port pairs.

spring.redis.timeout

=0

# Connection timeout in milliseconds.

# ----------------------------------------

# INTEGRATION PROPERTIES

# ----------------------------------------

# ACTIVEMQ (

ActiveMQProperties )

spring.activemq.broker-url

=

# URL of the ActiveMQ broker. Auto-generated by default. For instance

`tcp://localhost:61616`

spring.activemq.in-memory

=true

# Specify if the default broker URL should be in memory. Ignored if an

explicit broker has been specified.

spring.activemq.password

=

# Login password of the broker.

spring.activemq.pooled

=false

# Specify if a PooledConnectionFactory should be created instead of a

regular ConnectionFactory.

spring.activemq.user

=

# Login user of the broker.

# ARTEMIS (

ArtemisProperties )

spring.artemis.embedded.cluster-password

=

# Cluster password. Randomly generated on startup by default.

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spring.artemis.embedded.data-directory

=

# Journal file directory. Not necessary if persistence is turned

off.

spring.artemis.embedded.enabled

=true

# Enable embedded mode if the Artemis server APIs are available.

spring.artemis.embedded.persistent

=false

# Enable persistent store.

spring.artemis.embedded.queues

=

# Comma-separated list of queues to create on startup.

spring.artemis.embedded.server-id

=

# Server id. By default, an auto-incremented counter is used.

spring.artemis.embedded.topics

=

# Comma-separated list of topics to create on startup.

spring.artemis.host

=localhost

# Artemis broker host.

spring.artemis.mode

=

# Artemis deployment mode, auto-detected by default. Can be explicitly set to

"native" or "embedded".

spring.artemis.port

=61616

# Artemis broker port.

# SPRING BATCH (

BatchProperties )

spring.batch.initializer.enabled

=true

# Create the required batch tables on startup if necessary.

spring.batch.job.enabled

=true

# Execute all Spring Batch jobs in the context on startup.

spring.batch.job.names

=

# Comma-separated list of job names to execute on startup (For instance

`job1,job2`). By default, all Jobs found in the context are executed.

spring.batch.schema

=classpath:org/springframework/batch/core/[email protected]@[email protected]@.sql

# Path to the SQL

file to use to initialize the database schema.

spring.batch.table-prefix

=

# Table prefix for all the batch meta-data tables.

# HORNETQ (

HornetQProperties )

spring.hornetq.embedded.cluster-password

=

# Cluster password. Randomly generated on startup by default.

spring.hornetq.embedded.data-directory

=

# Journal file directory. Not necessary if persistence is turned

off.

spring.hornetq.embedded.enabled

=true

# Enable embedded mode if the HornetQ server APIs are available.

spring.hornetq.embedded.persistent

=false

# Enable persistent store.

spring.hornetq.embedded.queues

=

# Comma-separated list of queues to create on startup.

spring.hornetq.embedded.server-id

=

# Server id. By default, an auto-incremented counter is used.

spring.hornetq.embedded.topics

=

# Comma-separated list of topics to create on startup.

spring.hornetq.host

=localhost

# HornetQ broker host.

spring.hornetq.mode

=

# HornetQ deployment mode, auto-detected by default. Can be explicitly set to

"native" or "embedded".

spring.hornetq.port

=5445

# HornetQ broker port.

# JMS (

JmsProperties )

spring.jms.jndi-name

=

# Connection factory JNDI name. When set, takes precedence to others connection

factory auto-configurations.

spring.jms.listener.acknowledge-mode

=

# Acknowledge mode of the container. By default, the listener is

transacted with automatic acknowledgment.

spring.jms.listener.auto-startup

=true

# Start the container automatically on startup.

spring.jms.listener.concurrency

=

# Minimum number of concurrent consumers.

spring.jms.listener.max-concurrency

=

# Maximum number of concurrent consumers.

spring.jms.pub-sub-domain

=false

# Specify if the default destination type is topic.

# RABBIT (

RabbitProperties )

spring.rabbitmq.addresses

=

# Comma-separated list of addresses to which the client should connect to.

spring.rabbitmq.dynamic

=true

# Create an AmqpAdmin bean.

spring.rabbitmq.host

=localhost

# RabbitMQ host.

spring.rabbitmq.listener.acknowledge-mode

=

# Acknowledge mode of container.

spring.rabbitmq.listener.auto-startup

=true

# Start the container automatically on startup.

spring.rabbitmq.listener.concurrency

=

# Minimum number of consumers.

spring.rabbitmq.listener.max-concurrency

=

# Maximum number of consumers.

spring.rabbitmq.listener.prefetch

=

# Number of messages to be handled in a single request. It should be

greater than or equal to the transaction size (if used).

spring.rabbitmq.listener.transaction-size

=

# Number of messages to be processed in a transaction. For

best results it should be less than or equal to the prefetch count.

spring.rabbitmq.password

=

# Login to authenticate against the broker.

spring.rabbitmq.port

=5672

# RabbitMQ port.

spring.rabbitmq.requested-heartbeat

=

# Requested heartbeat timeout, in seconds; zero for none.

spring.rabbitmq.ssl.enabled

=false

# Enable SSL support.

spring.rabbitmq.ssl.key-store

=

# Path to the key store that holds the SSL certificate.

spring.rabbitmq.ssl.key-store-password

=

# Password used to access the key store.

spring.rabbitmq.ssl.trust-store

=

# Trust store that holds SSL certificates.

spring.rabbitmq.ssl.trust-store-password

=

# Password used to access the trust store.

spring.rabbitmq.username

=

# Login user to authenticate to the broker.

spring.rabbitmq.virtual-host

=

# Virtual host to use when connecting to the broker.

# ----------------------------------------

# ACTUATOR PROPERTIES

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# ----------------------------------------

# ENDPOINTS (

AbstractEndpoint subclasses)

endpoints.enabled

=true

# Enable endpoints.

endpoints.sensitive

=

# Default endpoint sensitive setting.

endpoints.actuator.enabled

=true

# Enable the endpoint.

endpoints.actuator.path

=

# Endpoint URL path.

endpoints.actuator.sensitive

=false

# Enable security on the endpoint.

endpoints.autoconfig.enabled

=

# Enable the endpoint.

endpoints.autoconfig.id

=

# Endpoint identifier.

endpoints.autoconfig.sensitive

=

# Mark if the endpoint exposes sensitive information.

endpoints.beans.enabled

=

# Enable the endpoint.

endpoints.beans.id

=

# Endpoint identifier.

endpoints.beans.sensitive

=

# Mark if the endpoint exposes sensitive information.

endpoints.configprops.enabled

=

# Enable the endpoint.

endpoints.configprops.id

=

# Endpoint identifier.

endpoints.configprops.keys-to-sanitize

=password,secret,key,.*credentials.*,vcap_services

# Keys that

should be sanitized. Keys can be simple strings that the property ends with or regex expressions.

endpoints.configprops.sensitive

=

# Mark if the endpoint exposes sensitive information.

endpoints.docs.curies.enabled

=false

# Enable the curie generation.

endpoints.docs.enabled

=true

# Enable actuator docs endpoint.

endpoints.docs.path

=/docs

#

endpoints.docs.sensitive

=false

#

endpoints.dump.enabled

=

# Enable the endpoint.

endpoints.dump.id

=

# Endpoint identifier.

endpoints.dump.sensitive

=

# Mark if the endpoint exposes sensitive information.

endpoints.env.enabled

=

# Enable the endpoint.

endpoints.env.id

=

# Endpoint identifier.

endpoints.env.keys-to-sanitize

=password,secret,key,.*credentials.*,vcap_services

# Keys that should be

sanitized. Keys can be simple strings that the property ends with or regex expressions.

endpoints.env.sensitive

=

# Mark if the endpoint exposes sensitive information.

endpoints.flyway.enabled

=

# Enable the endpoint.

endpoints.flyway.id

=

# Endpoint identifier.

endpoints.flyway.sensitive

=

# Mark if the endpoint exposes sensitive information.

endpoints.health.enabled

=

# Enable the endpoint.

endpoints.health.id

=

# Endpoint identifier.

endpoints.health.mapping.*

=

# Mapping of health statuses to HttpStatus codes. By default, registered

health statuses map to sensible defaults (i.e. UP maps to 200).

endpoints.health.sensitive

=

# Mark if the endpoint exposes sensitive information.

endpoints.health.time-to-live

=1000

# Time to live for cached result, in milliseconds.

endpoints.info.enabled

=

# Enable the endpoint.

endpoints.info.id

=

# Endpoint identifier.

endpoints.info.sensitive

=

# Mark if the endpoint exposes sensitive information.

endpoints.jolokia.enabled

=true

# Enable Jolokia endpoint.

endpoints.jolokia.path

=/jolokia

# Endpoint URL path.

endpoints.jolokia.sensitive

=true

# Enable security on the endpoint.

endpoints.liquibase.enabled

=

# Enable the endpoint.

endpoints.liquibase.id

=

# Endpoint identifier.

endpoints.liquibase.sensitive

=

# Mark if the endpoint exposes sensitive information.

endpoints.logfile.enabled

=true

# Enable the endpoint.

endpoints.logfile.path

=/logfile

# Endpoint URL path.

endpoints.logfile.sensitive

=true

# Enable security on the endpoint.

endpoints.mappings.enabled

=

# Enable the endpoint.

endpoints.mappings.id

=

# Endpoint identifier.

endpoints.mappings.sensitive

=

# Mark if the endpoint exposes sensitive information.

endpoints.metrics.enabled

=

# Enable the endpoint.

endpoints.metrics.filter.enabled

=true

# Enable the metrics servlet filter.

endpoints.metrics.id

=

# Endpoint identifier.

endpoints.metrics.sensitive

=

# Mark if the endpoint exposes sensitive information.

endpoints.shutdown.enabled

=

# Enable the endpoint.

endpoints.shutdown.id

=

# Endpoint identifier.

endpoints.shutdown.sensitive

=

# Mark if the endpoint exposes sensitive information.

endpoints.trace.enabled

=

# Enable the endpoint.

endpoints.trace.id

=

# Endpoint identifier.

endpoints.trace.sensitive

=

# Mark if the endpoint exposes sensitive information.

# ENDPOINTS CORS CONFIGURATION (

EndpointCorsProperties )

endpoints.cors.allow-credentials

=

# Set whether credentials are supported. When not set, credentials are

not supported.

endpoints.cors.allowed-headers

=

# Comma-separated list of headers to allow in a request. '*' allows all

headers.

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endpoints.cors.allowed-methods

=GET

# Comma-separated list of methods to allow. '*' allows all methods.

endpoints.cors.allowed-origins

=

# Comma-separated list of origins to allow. '*' allows all origins. When

not set, CORS support is disabled.

endpoints.cors.exposed-headers

=

# Comma-separated list of headers to include in a response.

endpoints.cors.max-age

=1800

# How long, in seconds, the response from a pre-flight request can be cached

by clients.

# JMX ENDPOINT (

EndpointMBeanExportProperties )

endpoints.jmx.domain

=

# JMX domain name. Initialized with the value of 'spring.jmx.default-domain' if

set.

endpoints.jmx.enabled

=true

# Enable JMX export of all endpoints.

endpoints.jmx.static-names

=

# Additional static properties to append to all ObjectNames of MBeans

representing Endpoints.

endpoints.jmx.unique-names

=false

# Ensure that ObjectNames are modified in case of conflict.

# JOLOKIA (

JolokiaProperties )

jolokia.config.*

=

# See Jolokia manual

# MANAGEMENT HTTP SERVER (

ManagementServerProperties )

management.add-application-context-header

=true

# Add the "X-Application-Context" HTTP header in each

response.

management.address

=

# Network address that the management endpoints should bind to.

management.context-path

=

# Management endpoint context-path. For instance `/actuator`

management.port

=

# Management endpoint HTTP port. Use the same port as the application by default.

management.security.enabled

=true

# Enable security.

management.security.role

=ADMIN

# Role required to access the management endpoint.

management.security.sessions

=stateless

# Session creating policy to use (always, never, if_required,

stateless).

# HEALTH INDICATORS (previously health.*)

management.health.db.enabled

=true

# Enable database health check.

management.health.defaults.enabled

=true

# Enable default health indicators.

management.health.diskspace.enabled

=true

# Enable disk space health check.

management.health.diskspace.path

=

# Path used to compute the available disk space.

management.health.diskspace.threshold

=0

# Minimum disk space that should be available, in bytes.

management.health.elasticsearch.enabled

=true

# Enable elasticsearch health check.

management.health.elasticsearch.indices

=

# Comma-separated index names.

management.health.elasticsearch.response-timeout

=100

# The time, in milliseconds, to wait for a response

from the cluster.

management.health.jms.enabled

=true

# Enable JMS health check.

management.health.mail.enabled

=true

# Enable Mail health check.

management.health.mongo.enabled

=true

# Enable MongoDB health check.

management.health.rabbit.enabled

=true

# Enable RabbitMQ health check.

management.health.redis.enabled

=true

# Enable Redis health check.

management.health.solr.enabled

=true

# Enable Solr health check.

management.health.status.order

=DOWN, OUT_OF_SERVICE, UNKNOWN, UP

# Comma-separated list of health

statuses in order of severity.

# TRACING ((

TraceProperties )

management.trace.include

=request-headers,response-headers,errors

# Items to be included in the trace.

# REMOTE SHELL

shell.auth

=simple

# Authentication type. Auto-detected according to the environment.

shell.auth.jaas.domain

=my-domain

# JAAS domain.

shell.auth.key.path

=

# Path to the authentication key. This should point to a valid ".pem" file.

shell.auth.simple.user.name

=user

# Login user.

shell.auth.simple.user.password

=

# Login password.

shell.auth.spring.roles

=ADMIN

# Comma-separated list of required roles to login to the CRaSH console.

shell.command-path-patterns

=classpath*:/commands/**,classpath*:/crash/commands/**

# Patterns to use to

look for commands.

shell.command-refresh-interval

=-1

# Scan for changes and update the command if necessary (in seconds).

shell.config-path-patterns

=classpath*:/crash/*

# Patterns to use to look for configurations.

shell.disabled-commands

=jpa*,jdbc*,jndi*

# Comma-separated list of commands to disable.

shell.disabled-plugins

=

# Comma-separated list of plugins to disable. Certain plugins are disabled by

default based on the environment.

shell.ssh.auth-timeout

=

# Number of milliseconds after user will be prompted to login again.

shell.ssh.enabled

=true

# Enable CRaSH SSH support.

shell.ssh.idle-timeout

=

# Number of milliseconds after which unused connections are closed.

shell.ssh.key-path

=

# Path to the SSH server key.

shell.ssh.port

=2000

# SSH port.

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shell.telnet.enabled

=false

# Enable CRaSH telnet support. Enabled by default if the TelnetPlugin is

available.

shell.telnet.port

=5000

# Telnet port.

# GIT INFO

spring.git.properties

=

# Resource reference to a generated git info properties file.

# METRICS EXPORT (

MetricExportProperties )

spring.metrics.export.aggregate.key-pattern

=

# Pattern that tells the aggregator what to do with the

keys from the source repository.

spring.metrics.export.aggregate.prefix

=

# Prefix for global repository if active.

spring.metrics.export.delay-millis

=5000

# Delay in milliseconds between export ticks. Metrics are

exported to external sources on a schedule with this delay.

spring.metrics.export.enabled

=true

# Flag to enable metric export (assuming a MetricWriter is

available).

spring.metrics.export.excludes

=

# List of patterns for metric names to exclude. Applied after the

includes.

spring.metrics.export.includes

=

# List of patterns for metric names to include.

spring.metrics.export.redis.key

=keys.spring.metrics

# Key for redis repository export (if active).

spring.metrics.export.redis.prefix

=spring.metrics

# Prefix for redis repository if active.

spring.metrics.export.send-latest

=

# Flag to switch off any available optimizations based on not

exporting unchanged metric values.

spring.metrics.export.statsd.host

=

# Host of a statsd server to receive exported metrics.

spring.metrics.export.statsd.port

=8125

# Port of a statsd server to receive exported metrics.

spring.metrics.export.statsd.prefix

=

# Prefix for statsd exported metrics.

spring.metrics.export.triggers.*

=

# Specific trigger properties per MetricWriter bean name.

# ----------------------------------------

# DEVTOOLS PROPERTIES

# ----------------------------------------

# DEVTOOLS (

DevToolsProperties )

spring.devtools.livereload.enabled

=true

# Enable a livereload.com compatible server.

spring.devtools.livereload.port

=35729

# Server port.

spring.devtools.restart.additional-exclude

=

# Additional patterns that should be excluded from

triggering a full restart.

spring.devtools.restart.additional-paths

=

# Additional paths to watch for changes.

spring.devtools.restart.enabled

=true

# Enable automatic restart.

spring.devtools.restart.exclude

=META-INF/maven/**,META-INF/resources/**,resources/**,static/**,public/

**,templates/**,**/*Test.class,**/*Tests.class,git.properties

# Patterns that should be excluded from

triggering a full restart.

spring.devtools.restart.poll-interval

=1000

# Amount of time (in milliseconds) to wait between polling

for classpath changes.

spring.devtools.restart.quiet-period

=400

# Amount of quiet time (in milliseconds) required without any

classpath changes before a restart is triggered.

spring.devtools.restart.trigger-file

=

# Name of a specific file that when changed will trigger the

restart check. If not specified any classpath file change will trigger the restart.

# REMOTE DEVTOOLS (

RemoteDevToolsProperties )

spring.devtools.remote.context-path

=/.~~spring-boot!~

# Context path used to handle the remote

connection.

spring.devtools.remote.debug.enabled

=true

# Enable remote debug support.

spring.devtools.remote.debug.local-port

=8000

# Local remote debug server port.

spring.devtools.remote.proxy.host

=

# The host of the proxy to use to connect to the remote application.

spring.devtools.remote.proxy.port

=

# The port of the proxy to use to connect to the remote application.

spring.devtools.remote.restart.enabled

=true

# Enable remote restart.

spring.devtools.remote.secret

=

# A shared secret required to establish a connection (required to enable

remote support).

spring.devtools.remote.secret-header-name

=X-AUTH-TOKEN

# HTTP header used to transfer the shared secret.

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Appendix B. Configuration meta-data

Spring Boot jars are shipped with meta-data files that provide details of all supported configuration properties. The files are designed to allow IDE developers to offer contextual help and “code completion” as users are working with application.properties

or application.yml

files.

The majority of the meta-data file is generated automatically at compile time by processing all items annotated with

@ConfigurationProperties

. However, it is possible to

write part of the meta-data manually

for corner cases or more advanced use cases.

B.1 Meta-data format

Configuration meta-data files are located inside jars under

META-INF/spring-configurationmetadata.json

They use a simple JSON format with items categorized under either “groups” or

“properties” and additional values hint categorized under "hints":

{

"groups"

:

[

{

"name"

:

"server"

,

"type"

:

"org.springframework.boot.autoconfigure.web.ServerProperties"

,

"sourceType"

:

"org.springframework.boot.autoconfigure.web.ServerProperties"

},

{

"name"

:

"spring.jpa.hibernate"

,

"type"

:

"org.springframework.boot.autoconfigure.orm.jpa.JpaProperties$Hibernate"

,

"sourceType"

:

"org.springframework.boot.autoconfigure.orm.jpa.JpaProperties"

,

"sourceMethod"

:

"getHibernate()"

}

...

],

"properties"

:

[

{

"name"

:

"server.port"

,

"type"

:

"java.lang.Integer"

,

"sourceType"

:

"org.springframework.boot.autoconfigure.web.ServerProperties"

},

{

"name"

:

"server.servlet-path"

,

"type"

:

"java.lang.String"

,

"sourceType"

:

"org.springframework.boot.autoconfigure.web.ServerProperties"

,

"defaultValue"

:

"/"

},

{

"name"

:

"spring.jpa.hibernate.ddl-auto"

,

"type"

:

"java.lang.String"

,

"description"

:

"DDL mode. This is actually a shortcut for the \"hibernate.hbm2ddl.auto\"

property."

,

"sourceType"

:

"org.springframework.boot.autoconfigure.orm.jpa.JpaProperties$Hibernate"

}

...

],

"hints"

:

[

{

"name"

:

"spring.jpa.hibernate.ddl-auto"

,

"values"

:

[

{

"value"

:

"none"

,

"description"

:

"Disable DDL handling."

},

{

"value"

:

"validate"

,

"description"

:

"Validate the schema, make no changes to the database."

},

{

"value"

:

"update"

,

"description"

:

"Update the schema if necessary."

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},

{

"value"

:

"create"

,

"description"

:

"Create the schema and destroy previous data."

},

{

"value"

:

"create-drop"

,

"description"

:

"Create and then destroy the schema at the end of the session."

}

]

}

]

}

Each “property” is a configuration item that the user specifies with a given value. For example server.port

and server.servlet-path

might be specified in application.properties

as follows:

server.port

=9090

server.servlet-path

=/home

The “groups” are higher level items that don’t themselves specify a value, but instead provide a contextual grouping for properties. For example the server.port

and server.servlet-path properties are part of the server

group.

Note

It is not required that every “property” has a “group”, some properties might just exist in their own right.

Finally, “hints” are additional information used to assist the user in configuring a given property. When configuring the spring.jpa.hibernate.ddl-auto

property, a tool can use it to offer some autocompletion help for the none

, validate

, update

, create

and create-drop

values.

Group Attributes

The JSON object contained in the groups

array can contain the following attributes:

Name

name type

Type

String

String description

String sourceType

String

Purpose

The full name of the group. This attribute is mandatory.

The class name of the data type of the group. For example, if the group was based on a class annotated with

@ConfigurationProperties

the attribute would contain the fully qualified name of that class. If it was based on a

@Bean method, it would be the return type of that method. The attribute may be omitted if the type is not known.

A short description of the group that can be displayed to users.

May be omitted if no description is available. It is recommended that descriptions are a short paragraphs, with the first line providing a concise summary. The last line in the description should end with a period (

.

).

The class name of the source that contributed this group. For example, if the group was based on a

@Bean

method annotated

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Name Type

sourceMethod

String

Purpose

with

@ConfigurationProperties

this attribute would contain the fully qualified name of the

@Configuration

class containing the method. The attribute may be omitted if the source type is not known.

The full name of the method (include parenthesis and argument types) that contributed this group. For example, the name of a

@ConfigurationProperties

annotated

@Bean

method. May be omitted if the source method is not known.

Property Attributes

The JSON object contained in the properties

array can contain the following attributes:

Name

name type description sourceType defaultValue

Type

String

String

String

String

Object

Purpose

The full name of the property. Names are in lowercase dashed form (e.g. server.servlet-path

). This attribute is mandatory.

The class name of the data type of the property. For example, java.lang.String

. This attribute can be used to guide the user as to the types of values that they can enter. For consistency, the type of a primitive is specified using its wrapper counterpart, i.e.

boolean

becomes java.lang.Boolean

. Note that this class may be a complex type that gets converted from a String as values are bound. May be omitted if the type is not known.

A short description of the group that can be displayed to users.

May be omitted if no description is available. It is recommended that descriptions are a short paragraphs, with the first line providing a concise summary. The last line in the description should end with a period (

.

).

The class name of the source that contributed this property.

For example, if the property was from a class annotated with

@ConfigurationProperties

this attribute would contain the fully qualified name of that class. May be omitted if the source type is not known.

The default value which will be used if the property is not specified.

Can also be an array of value(s) if the type of the property is an array. May be omitted if the default value is not known.

deprecation

Deprecation Specify if the property is deprecated. May be omitted if the field is not deprecated or if that information is not known. See below for more details.

The JSON object contained in the deprecation

attribute of each properties

element can contain the following attributes:

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Name

reason

Type

String replacement

String

Purpose

A short description of the reason why the property was deprecated. May be omitted if no reason is available. It is recommended that descriptions are a short paragraphs, with the first line providing a concise summary. The last line in the description should end with a period (

.

).

The full name of the property that is replacing this deprecated property. May be omitted if there is no replacement for this property.

Note

Prior to Spring Boot 1.3, a single deprecated

boolean attribute can be used instead of the deprecation

element. This is still supported in a deprecated fashion and should no longer be used. If no reason and replacement are available, an empty deprecation

object should be set.

Hint Attributes

The JSON object contained in the hints

array can contain the following attributes:

Name

name values providers

Type

String

ValueHint[]

Purpose

The full name of the property that this hint refers to. Names are in lowercase dashed form (e.g. server.servlet-path

). If the property refers to a map (e.g. system.contexts

) the hint either applies to the keys of the map ( system.context.keys

) or the values ( system.context.values

). This attribute is mandatory.

A list of valid values as defined by the

ValueHint

object (see below). Each entry defines the value and may have a description

ValueProvider[] A list of providers as defined by the

ValueProvider

object

(see below). Each entry defines the name of the provider and its parameters, if any.

The JSON object contained in the values

attribute of each hint

element can contain the following attributes:

Name

value

Type

Object description

String

Purpose

A valid value for the element to which the hint refers to. Can also be an array of value(s) if the type of the property is an array. This attribute is mandatory.

A short description of the value that can be displayed to users.

May be omitted if no description is available. It is recommended that descriptions are a short paragraphs, with the first line providing a concise summary. The last line in the description should end with a period (

.

).

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The JSON object contained in the providers

attribute of each hint

element can contain the following attributes:

Name

name

Type

String

Purpose

The name of the provider to use to offer additional content assistance for the element to which the hint refers to.

parameters

JSON object Any additional parameter that the provider supports (check the documentation of the provider for more details).

Repeated meta-data items

It is perfectly acceptable for “property” and “group” objects with the same name to appear multiple times within a meta-data file. For example, Spring Boot binds spring.datasource

properties to Hikari,

Tomcat and DBCP classes, with each potentially offering overlap of property names. Consumers of meta-data should take care to ensure that they support such scenarios.

B.2 Providing manual hints

To improve the user experience and further assist the user in configuring a given property, you can provide additional meta-data that:

1. Describes the list of potential values for a property.

2. Associates a provider to attach a well-defined semantic to a property so that a tool can discover the list of potential values based on the project’s context.

Value hint

The name

attribute of each hint refers to the name

of a property. In the initial example above, we provide

5 values for the spring.jpa.hibernate.ddl-auto

property: none

, validate

, update

, create and create-drop

. Each value may have a description as well.

If your property is of type

Map

, you can provide hints for both the keys and the values (but not for the map itself). The special

.keys

and

.values

suffixes must be used to refer to the keys and the values respectively.

Let’s assume a foo.contexts

that maps magic String values to an integer:

@ConfigurationProperties("foo")

public class

FooProperties {

private

Map<String,Integer> contexts;

// getters and setters

}

The magic values are foo and bar for instance. In order to offer additional content assistance for the keys, you could add the following to

the manual meta-data of the module :

{

"hints"

:

[

{

"name"

:

"foo.contexts.keys"

,

"values"

:

[

{

"value"

:

"foo"

},

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{

"value"

:

"bar"

}

]

}

]

}

Note

Of course, you should have an

Enum

for those two values instead. This is by far the most effective approach to auto-completion if your IDE supports it.

Value provider

Providers are a powerful way of attaching semantics to a property. We define in the section below the official providers that you can use for your own hints. Bare in mind however that your favorite IDE may implement some of these or none of them. It could eventually provide its own as well.

Note

As this is a new feature, IDE vendors will have to catch up with this new feature.

The table below summarizes the list of supported providers:

Name

any class-reference handle-as logger-name spring-bean-reference spring-profile-name

Description

Permit any additional value to be provided.

Auto-complete the classes available in the project. Usually constrained by a base class that is specified via the target parameter.

Handle the property as if it was defined by the type defined via the mandatory target

parameter.

Auto-complete valid logger names. Typically, package and class names available in the current project can be auto-completed.

Auto-complete the available bean names in the current project.

Usually constrained by a base class that is specified via the target

parameter.

Auto-complete the available Spring profile names in the project.

Tip

No more than one provider can be active for a given property but you can specify several providers if they can all manage the property in some ways. Make sure to place the most powerful provider first as the IDE must use the first one in the JSON section it can handle. If no provider for a given property is supported, no special content assistance is provided either.

Any

The any provider permits any additional values to be provided. Regular value validation based on the property type should be applied if this is supported.

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This provider will be typically used if you have a list of values and any extra values are still to be considered as valid.

The example below offers on

and off

as auto-completion values for system.state

; any other value is also allowed:

{

"hints"

:

[

{

"name"

:

"system.state"

,

"values"

:

[

{

"value"

:

"on"

},

{

"value"

:

"off"

}

]

,

"providers"

:

[

{

"name"

:

"any"

}

]

}

]

}

Class reference

The class-reference provider auto-completes classes available in the project. This provider supports these parameters:

Parameter Type

target String

(

Class

) concrete boolean

Default value

none

true

Description

The fully qualified name of the class that should be assignable to the chosen value. Typically used to filter out non candidate classes. Note that this information can be provided by the type itself by exposing a class with the appropriate upper bound.

Specify if only concrete classes are to be considered as valid candidates.

The meta-data snippet below corresponds to the standard server.jsp-servlet.class-name property that defines the

JspServlet

class name to use:

{

"hints"

:

[

{

"name"

:

"server.jsp-servlet.class-name"

,

"providers"

:

[

{

"name"

:

"class-reference"

,

"parameters"

:

{

"target"

:

"javax.servlet.http.HttpServlet"

}

}

]

}

]

}

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Handle As

The handle-as provider allows you to substitute the type of the property to a more high-level type. This typically happens when the property has a java.lang.String

type because you don’t want your configuration classes to rely on classes that may not be on the classpath. This provider supports these parameters:

Parameter Type target

String

(

Class

)

Default value

none

Description

The fully qualified name of the type to consider for the property. This parameter is mandatory.

The following types can be used:

• Any java.lang.Enum

that lists the possible values for the property (By all means, try to define the property with the

Enum

type instead as no further hint should be required for the IDE to auto-complete the values).

• java.nio.charset.Charset

: auto-completion of charset/encoding values (e.g.

UTF-8

)

• java.util.Locale

: auto-completion of locales (e.g. en_US

)

• org.springframework.util.MimeType

: auto-completion of content type values (e.g. text/ plain

)

• org.springframework.core.io.Resource

: auto-completion of Spring’s Resource abstraction to refer to a file on the filesystem or on the classpath. (e.g. classpath:/foo.properties

)

Note

If multiple values can be provided, use a

Collection

or Array type to teach the IDE about it.

The meta-data snippet below corresponds to the standard liquibase.change-log

property that defines the path to the changelog to use. It is actually used internally as a org.springframework.core.io.Resource

but cannot be exposed as such as we need to keep the original String value to pass it to the Liquibase API.

{

"hints"

:

[

{

"name"

:

"liquibase.change-log"

,

"providers"

:

[

{

"name"

:

"handle-as"

,

"parameters"

:

{

"target"

:

"org.springframework.core.io.Resource"

}

}

]

}

]

}

Logger name

The logger-name provider auto-completes valid logger names. Typically, package and class names available in the current project can be auto-completed. Specific frameworks may have extra magic logger names that could be supported as well.

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Since a logger name can be any arbitrary name, really, this provider should allow any value but could highlight valid packages and class names that are not available in the project’s classpath.

The meta-data snippet below corresponds to the standard logging.level

property, keys are logger

names and values correspond to the standard log levels or any custom level:

{

"hints"

:

[

{

"name"

:

"logging.level.keys"

,

"values"

:

[

{

"value"

:

"root"

,

"description"

:

"Root logger used to assign the default logging level."

}

]

,

"providers"

:

[

{

"name"

:

"logger-name"

}

]

},

{

"name"

:

"logging.level.values"

,

"values"

:

[

{

"value"

:

"trace"

},

{

"value"

:

"debug"

},

{

"value"

:

"info"

},

{

"value"

:

"warn"

},

{

"value"

:

"error"

},

{

"value"

:

"fatal"

},

{

"value"

:

"off"

}

]

,

"providers"

:

[

{

"name"

:

"any"

}

]

}

]

}

Spring bean reference

The spring-bean-reference provider auto-completes the beans that are defined in the configuration of the current project. This provider supports these parameters:

Parameter Type

target String

(

Class

)

Default value

none

Description

The fully qualified name of the bean class that should be assignable to the candidate. Typically used to filter out non candidate beans.

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The meta-data snippet below corresponds to the standard spring.jmx.server

property that defines the name of the

MBeanServer

bean to use:

{

"hints"

:

[

{

"name"

:

"spring.jmx.server"

,

"providers"

:

[

{

"name"

:

"spring-bean-reference"

,

"parameters"

:

{

"target"

:

"javax.management.MBeanServer"

}

}

]

}

]

}

Note

The binder is not aware of the meta-data so if you provide that hint, you will still need to transform the bean name into an actual Bean reference using the

ApplicationContext

.

Spring profile name

The spring-profile-name provider auto-completes the Spring profiles that are defined in the configuration of the current project.

The meta-data snippet below corresponds to the standard spring.profiles.active

property that defines the name of the Spring profile(s) to enable:

{

"hints"

:

[

{

"name"

:

"spring.profiles.active"

,

"providers"

:

[

{

"name"

:

"spring-profile-name"

}

]

}

]

}

B.3 Generating your own meta-data using the annotation processor

You can easily generate your own configuration meta-data file from items annotated with

@ConfigurationProperties

by using the spring-boot-configuration-processor

jar. The jar includes a Java annotation processor which is invoked as your project is compiled. To use the processor, simply include spring-boot-configuration-processor

as an optional dependency, for example with Maven you would add:

<dependency>

<groupId>

org.springframework.boot

</groupId>

<artifactId>

spring-boot-configuration-processor

</artifactId>

<optional>

true

</optional>

</dependency>

With Gradle, you can use the propdeps-plugin and specify:

dependencies {

optional

"org.springframework.boot:spring-boot-configuration-processor"

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}

compileJava.dependsOn(processResources)

}

Note

You need to add compileJava.dependsOn(processResources)

to your build to ensure that resources are processed before code is compiled. Without this directive any additionalspring-configuration-metadata.json

files will not be processed.

The processor will pick up both classes and methods that are annotated with

@ConfigurationProperties

. The Javadoc for field values within configuration classes will be used to populate the description

attribute.

Note

You should only use simple text with

@ConfigurationProperties

field Javadoc since they are not processed before being added to the JSON.

Properties are discovered via the presence of standard getters and setters with special handling for collection types (that will be detected even if only a getter is present). The annotation processor also supports the use of the

@Data

,

@Getter

and

@Setter

lombok annotations.

Nested properties

The annotation processor will automatically consider inner classes as nested properties. For example, the following class:

@ConfigurationProperties(prefix="server")

public class

ServerProperties {

private

String name;

private

Host host;

// ... getter and setters

private static class

Host {

private

String ip;

private int

port;

// ... getter and setters

}

}

Will produce meta-data information for server.name

, server.host.ip

and server.host.port

properties. You can use the

@NestedConfigurationProperty

annotation on a field to indicate that a regular (non-inner) class should be treated as if it were nested.

Adding additional meta-data

Spring Boot’s configuration file handling is quite flexible; and it is often the case that properties may exist that are not bound to a

@ConfigurationProperties

bean. You may also need to tune

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META-INF/additional-springconfiguration-metadata.json

into the main meta-data file.

If you refer to a property that has been detected automatically, the description, default value and deprecation information are overridden if specified. If the manual property declaration is not identified in the current module, it is added as a brand new property.

The format of the additional-spring-configuration-metadata.json

file is exactly the same as the regular spring-configuration-metadata.json

. The additional properties file is optional, if you don’t have any additional properties, simply don’t add it.

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Appendix C. Auto-configuration classes

Here is a list of all auto-configuration classes provided by Spring Boot with links to documentation and source code. Remember to also look at the autoconfig report in your application for more details of which features are switched on. (start the app with

--debug

or

-Ddebug

, or in an Actuator application use the autoconfig

endpoint).

C.1 From the “spring-boot-autoconfigure” module

The following auto-configuration classes are from the spring-boot-autoconfigure

module:

Configuration Class

ActiveMQAutoConfiguration

AopAutoConfiguration

ArtemisAutoConfiguration

BatchAutoConfiguration

CacheAutoConfiguration

CassandraAutoConfiguration

CassandraDataAutoConfiguration

CassandraRepositoriesAutoConfiguration

CloudAutoConfiguration

ConfigurationPropertiesAutoConfiguration

DataSourceAutoConfiguration

DataSourceTransactionManagerAutoConfiguration

DeviceDelegatingViewResolverAutoConfiguration

DeviceResolverAutoConfiguration

DispatcherServletAutoConfiguration

ElasticsearchAutoConfiguration

ElasticsearchDataAutoConfiguration

ElasticsearchRepositoriesAutoConfiguration

EmbeddedMongoAutoConfiguration

EmbeddedServletContainerAutoConfiguration

ErrorMvcAutoConfiguration

FacebookAutoConfiguration javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc

Links

javadoc javadoc javadoc javadoc javadoc

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Configuration Class

FallbackWebSecurityAutoConfiguration

FlywayAutoConfiguration

FreeMarkerAutoConfiguration

GroovyTemplateAutoConfiguration

GsonAutoConfiguration

H2ConsoleAutoConfiguration

HazelcastAutoConfiguration

HazelcastJpaDependencyAutoConfiguration

HibernateJpaAutoConfiguration

HornetQAutoConfiguration

HttpEncodingAutoConfiguration

HttpMessageConvertersAutoConfiguration

HypermediaAutoConfiguration

IntegrationAutoConfiguration

JacksonAutoConfiguration

JerseyAutoConfiguration

JmsAutoConfiguration

JmxAutoConfiguration

JndiConnectionFactoryAutoConfiguration

JndiDataSourceAutoConfiguration

JooqAutoConfiguration

JpaRepositoriesAutoConfiguration

JtaAutoConfiguration

LinkedInAutoConfiguration

LiquibaseAutoConfiguration

MailSenderAutoConfiguration

MailSenderValidatorAutoConfiguration

MessageSourceAutoConfiguration

MongoAutoConfiguration

MongoDataAutoConfiguration

1.3.1.BUILD-SNAPSHOT Spring Boot javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc

Links

javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc

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Configuration Class

MongoRepositoriesAutoConfiguration

MultipartAutoConfiguration

MustacheAutoConfiguration

OAuth2AutoConfiguration

PersistenceExceptionTranslationAutoConfiguration

PropertyPlaceholderAutoConfiguration

RabbitAutoConfiguration

ReactorAutoConfiguration

RedisAutoConfiguration

RepositoryRestMvcAutoConfiguration

SecurityAutoConfiguration

SecurityFilterAutoConfiguration

SendGridAutoConfiguration

ServerPropertiesAutoConfiguration

SessionAutoConfiguration

SitePreferenceAutoConfiguration

SocialWebAutoConfiguration

SolrAutoConfiguration

SolrRepositoriesAutoConfiguration

SpringApplicationAdminJmxAutoConfiguration

SpringDataWebAutoConfiguration

ThymeleafAutoConfiguration

TransactionAutoConfiguration

TwitterAutoConfiguration

VelocityAutoConfiguration

WebMvcAutoConfiguration

WebSocketAutoConfiguration

WebSocketMessagingAutoConfiguration

XADataSourceAutoConfiguration javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc

Links

javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc

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C.2 From the “spring-boot-actuator” module

The following auto-configuration classes are from the spring-boot-actuator

module:

Configuration Class

AuditAutoConfiguration

CacheStatisticsAutoConfiguration

CrshAutoConfiguration

EndpointAutoConfiguration

EndpointMBeanExportAutoConfiguration

EndpointWebMvcAutoConfiguration

HealthIndicatorAutoConfiguration

JolokiaAutoConfiguration

ManagementServerPropertiesAutoConfiguration

ManagementWebSecurityAutoConfiguration

MetricExportAutoConfiguration

MetricFilterAutoConfiguration

MetricRepositoryAutoConfiguration

MetricsChannelAutoConfiguration

MetricsDropwizardAutoConfiguration

PublicMetricsAutoConfiguration

TraceRepositoryAutoConfiguration

TraceWebFilterAutoConfiguration javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc javadoc

Links

javadoc javadoc javadoc javadoc javadoc javadoc javadoc

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Appendix D. The executable jar format

The spring-boot-loader

modules allows Spring Boot to support executable jar and war files. If you’re using the Maven or Gradle plugin, executable jars are automatically generated and you generally won’t need to know the details of how they work.

If you need to create executable jars from a different build system, or if you are just curious about the underlying technology, this section provides some background.

D.1 Nested JARs

Java does not provide any standard way to load nested jar files (i.e. jar files that are themselves contained within a jar). This can be problematic if you are looking to distribute a self-contained application that you can just run from the command line without unpacking.

To solve this problem, many developers use “shaded” jars. A shaded jar simply packages all classes, from all jars, into a single 'uber jar'. The problem with shaded jars is that it becomes hard to see which libraries you are actually using in your application. It can also be problematic if the same filename is used (but with different content) in multiple jars. Spring Boot takes a different approach and allows you to actually nest jars directly.

The executable jar file structure

Spring Boot Loader compatible jar files should be structured in the following way: example.jar

|

+-META-INF

| +-MANIFEST.MF

+-org

| +-springframework

| +-boot

| +-loader

| +-<spring boot loader classes>

+-com

| +-mycompany

| + project

| +-YouClasses.class

+-lib

+-dependency1.jar

+-dependency2.jar

Dependencies should be placed in a nested lib

directory.

The executable war file structure

Spring Boot Loader compatible war files should be structured in the following way: example.war

|

+-META-INF

| +-MANIFEST.MF

+-org

| +-springframework

| +-boot

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| +-loader

| +-<spring boot loader classes>

+-WEB-INF

+-classes

| +-com

| +-mycompany

| +-project

| +-YouClasses.class

+-lib

| +-dependency1.jar

| +-dependency2.jar

+-lib-provided

+-servlet-api.jar

+-dependency3.jar

Dependencies should be placed in a nested

WEB-INF/lib

directory. Any dependencies that are required when running embedded but are not required when deploying to a traditional web container should be placed in

WEB-INF/lib-provided

.

D.2 Spring Boot’s “JarFile” class

The core class used to support loading nested jars is org.springframework.boot.loader.jar.JarFile

. It allows you load jar content from a standard jar file, or from nested child jar data. When first loaded, the location of each

JarEntry

is mapped to a physical file offset of the outer jar: myapp.jar

+---------+---------------------+

| | /lib/mylib.jar |

| A.class |+---------+---------+|

| || B.class | B.class ||

| |+---------+---------+|

+---------+---------------------+

^ ^ ^

0063 3452 3980

The example above shows how

A.class

can be found in myapp.jar

position

0063

.

B.class

from the nested jar can actually be found in myapp.jar

position

3452

and

B.class

is at position

3980

.

Armed with this information, we can load specific nested entries by simply seeking to appropriate part if the outer jar. We don’t need to unpack the archive and we don’t need to read all entry data into memory.

Compatibility with the standard Java “JarFile”

Spring Boot Loader strives to remain compatible with existing code and libraries.

org.springframework.boot.loader.jar.JarFile

extends from java.util.jar.JarFile

and should work as a drop-in replacement. The getURL()

method will return a

URL

that opens a java.net.JarURLConnection

compatible connection and can be used with Java’s

URLClassLoader

.

D.3 Launching executable jars

The org.springframework.boot.loader.Launcher

class is a special bootstrap class that is used as an executable jars main entry point. It is the actual

Main-Class

in your jar file and it’s used to setup an appropriate

URLClassLoader

and ultimately call your main()

method.

There are 3 launcher subclasses (

JarLauncher

,

WarLauncher

and

PropertiesLauncher

). Their purpose is to load resources (

.class

files etc.) from nested jar files or war files in directories (as

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[Jar|War]Launcher

the nested paths are fixed ( lib/*.jar

and lib-provided/*.jar

for the war case) so you just add extra jars in those locations if you want more. The

PropertiesLauncher

looks in lib/

in your application archive by default, but you can add additional locations by setting an environment variable

LOADER_PATH

or loader.path

in application.properties

(comma-separated list of directories or archives).

Launcher manifest

You need to specify an appropriate

Launcher

as the

Main-Class

attribute of

META-INF/

MANIFEST.MF

. The actual class that you want to launch (i.e. the class that you wrote that contains a main

method) should be specified in the

Start-Class

attribute.

For example, here is a typical

MANIFEST.MF

for an executable jar file:

Main-Class: org.springframework.boot.loader.JarLauncher

Start-Class: com.mycompany.project.MyApplication

For a war file, it would be:

Main-Class: org.springframework.boot.loader.WarLauncher

Start-Class: com.mycompany.project.MyApplication

Note

You do not need to specify

Class-Path

entries in your manifest file, the classpath will be deduced from the nested jars.

Exploded archives

Certain PaaS implementations may choose to unpack archives before they run. For example, Cloud

Foundry operates in this way. You can run an unpacked archive by simply starting the appropriate launcher:

$ unzip -q myapp.jar

$ java org.springframework.boot.loader.JarLauncher

D.4 PropertiesLauncher Features

PropertiesLauncher

has a few special features that can be enabled with external properties (System properties, environment variables, manifest entries or application.properties

).

Key

loader.path

loader.home

loader.args

loader.main

Purpose

Comma-separated Classpath, e.g. lib,${HOME}/app/lib

.

Earlier entries take precedence, just like a regular

-classpath on the javac

command line.

Location of additional properties file, e.g.

/opt/app

(defaults to

${user.dir}

)

Default arguments for the main method (space separated)

Name of main class to launch, e.g. com.app.Application

.

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Key

loader.config.name

Purpose

Name of properties file, e.g. loader

(defaults to application

).

loader.config.location

Path to properties file, e.g. classpath:loader.properties

(defaults to application.properties

).

loader.system

Boolean flag to indicate that all properties should be added to

System properties (defaults to false

)

Manifest entry keys are formed by capitalizing initial letters of words and changing the separator to “-” from “.” (e.g.

Loader-Path

). The exception is loader.main

which is looked up as

Start-Class

in the manifest for compatibility with

JarLauncher

).

Tip

Build plugins automatically move the

Main-Class

attribute to

Start-Class

when the fat jar is built. If you are using that, specify the name of the class to launch using the

Main-Class

attribute and leave out

Start-Class

.

Environment variables can be capitalized with underscore separators instead of periods.

• loader.home

is the directory location of an additional properties file (overriding the default) as long as loader.config.location

is not specified.

• loader.path

can contain directories (scanned recursively for jar and zip files), archive paths, or wildcard patterns (for the default JVM behavior).

• loader.path

(if empty) defaults to lib

(meaning a local directory or a nested one if running from an archive). Because of this

PropertiesLauncher

behaves the same as

JarLauncher

when no additional configuration is provided.

• Placeholder replacement is done from System and environment variables plus the properties file itself on all values before use.

D.5 Executable jar restrictions

There are a number of restrictions that you need to consider when working with a Spring Boot Loader packaged application.

Zip entry compression

The

ZipEntry

for a nested jar must be saved using the

ZipEntry.STORED

method. This is required so that we can seek directly to individual content within the nested jar. The content of the nested jar file itself can still be compressed, as can any other entries in the outer jar.

System ClassLoader

Launched applications should use

Thread.getContextClassLoader()

when loading classes

(most libraries and frameworks will do this by default). Trying to load nested jar classes via

ClassLoader.getSystemClassLoader()

will fail. Please be aware that java.util.Logging

always uses the system classloader, for this reason you should consider a different logging implementation.

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D.6 Alternative single jar solutions

If the above restrictions mean that you cannot use Spring Boot Loader the following alternatives could be considered:

• Maven Shade Plugin

• JarClassLoader

• OneJar

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Appendix E. Dependency versions

The table below provides details of all of the dependency versions that are provided by Spring Boot in its CLI, Maven dependency management and Gradle plugin. When you declare a dependency on one of these artifacts without declaring a version the version that is listed in the table will be used.

Group ID

antlr ch.qos.logback

ch.qos.logback

com.atomikos

com.atomikos

com.atomikos

com.datastax.cassandra

com.datastax.cassandra

Artifact ID

antlr logback-access logback-classic transactions-jdbc transactions-jms transactions-jta cassandra-driver-core cassandra-driver-dse com.datastax.cassandra

cassandra-drivermapping

2.6.4

2.6.4

2.6.4

com.fasterxml.jackson.dataformat

2.6.4

com.fasterxml.jackson.dataformat

2.6.4

com.fasterxml.jackson.dataformat

2.6.4

2.6.4

Version

2.7.7

1.1.3

1.1.3

3.9.3

3.9.3

3.9.3

2.1.9

2.1.9

2.1.9

hibernate4

2.6.4

2.6.4

2.6.4

2.6.4

com.fasterxml.jackson.datatype

2.6.4

2.6.4

parameter-names com.gemstone.gemfire

hibernate5 gemfire

8.1.0

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Group ID Artifact ID Version

1.3

com.google.code.gson

com.googlecode.jsonsimple com.h2database

com.hazelcast

com.hazelcast

com.hazelcast

com.jayway.jsonpath

com.jayway.jsonpath

com.samskivert

com.sendgrid

com.sun.mail

com.timgroup

com.zaxxer

com.zaxxer

commons-beanutils commons-collections commons-dbcp commons-digester commons-pool de.flapdoodle.embed

io.dropwizard.metrics

io.dropwizard.metrics

io.dropwizard.metrics

io.dropwizard.metrics

io.projectreactor

io.projectreactor

io.projectreactor

attribute gson json-simple

2.3.1

1.1.1

h2 hazelcast hazelcast-hibernate4 hazelcast-spring json-path json-path-assert jmustache sendgrid-java javax.mail

java-statsd-client

HikariCP

HikariCP-java6 commons-beanutils commons-collections commons-dbcp commons-digester

1.4

2.1

commons-pool

1.6

de.flapdoodle.embed.mongo

1.50.1

metrics-core metrics-ganglia

3.1.2

3.1.2

metrics-graphite metrics-servlets reactor-bus reactor-core reactor-groovy

3.1.2

3.1.2

2.0.7.RELEASE

2.0.7.RELEASE

2.0.7.RELEASE

2.2.2

1.5.4

3.1.0

2.4.3

2.3.12

1.9.2

3.2.2

1.4.190

3.5.4

3.5.4

3.5.4

2.0.0

2.0.0

1.11

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Group ID

io.projectreactor

Artifact ID

reactor-groovyextensions

Version

2.0.7.RELEASE

io.projectreactor

io.projectreactor

reactor-logback reactor-net

2.0.7.RELEASE

2.0.7.RELEASE

io.projectreactor

reactor-stream

2.0.7.RELEASE

io.projectreactor.spring reactor-spring-context

2.0.7.RELEASE

io.projectreactor.spring reactor-spring-core io.projectreactor.spring reactor-springmessaging

2.0.7.RELEASE

2.0.7.RELEASE

io.projectreactor.spring reactor-spring-webmvc io.undertow

io.undertow

io.undertow

javax.cache

javax.jms

javax.mail

javax.servlet

javax.servlet

javax.transaction

undertow-core undertow-servlet

2.0.7.RELEASE

1.3.10.Final

1.3.10.Final

undertow-websockets-jsr

1.3.10.Final

cache-api

1.0.0

jms-api javax.mail-api

1.1-rev-1

1.5.4

javax.servlet-api jstl javax.transaction-api

3.1.0

1.2

1.2

jaxen joda-time junit log4j mysql net.sf.ehcache

net.sourceforge.nekohtml nekohtml nz.net.ultraq.thymeleaf

jaxen joda-time junit log4j mysql-connector-java ehcache thymeleaf-layoutdialect

1.1.6

2.8.2

4.12

1.2.17

5.1.38

2.10.1

1.9.22

1.3.1

org.apache.activemq

org.apache.activemq

org.apache.activemq

activemq-amqp activemq-blueprint activemq-broker

5.12.1

5.12.1

5.12.1

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Group ID

org.apache.activemq

org.apache.activemq

org.apache.activemq

org.apache.activemq

org.apache.activemq

org.apache.activemq

org.apache.activemq

org.apache.activemq

org.apache.activemq

org.apache.activemq

org.apache.activemq

org.apache.activemq

org.apache.activemq

org.apache.activemq

org.apache.activemq

org.apache.activemq

org.apache.activemq

org.apache.activemq

org.apache.activemq

org.apache.activemq

org.apache.activemq

org.apache.activemq

org.apache.activemq

org.apache.activemq

org.apache.activemq

org.apache.activemq

org.apache.commons

org.apache.commons

org.apache.derby

Artifact ID

activemq-camel activemq-client activemq-console

Version

5.12.1

5.12.1

5.12.1

activemq-http activemq-jaas activemq-jdbc-store activemq-jms-pool

5.12.1

5.12.1

5.12.1

5.12.1

activemq-kahadb-store

5.12.1

5.12.1

activemq-karaf activemq-leveldb-store

5.12.1

activemq-log4j-appender

5.12.1

activemq-mqtt

5.12.1

activemq-openwiregenerator

5.12.1

activemq-openwirelegacy

5.12.1

activemq-osgi activemq-partition activemq-pool

5.12.1

5.12.1

5.12.1

activemq-ra activemq-run

5.12.1

5.12.1

activemq-runtime-config

5.12.1

activemq-shiro

5.12.1

activemq-spring activemq-stomp

5.12.1

5.12.1

activemq-web artemis-jms-client artemis-jms-server commons-dbcp2 commons-pool2 derby

5.12.1

1.1.0

1.1.0

2.1.1

2.4.2

10.12.1.1

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Group ID Artifact ID

org.apache.httpcomponentshttpasyncclient

org.apache.httpcomponentshttpclient

org.apache.httpcomponentshttpcore

org.apache.httpcomponentshttpmime

org.apache.logging.log4j log4j-api org.apache.logging.log4j log4j-core org.apache.logging.log4j log4j-slf4j-impl org.apache.solr

org.apache.tomcat

solr-solrj tomcat-jdbc org.apache.tomcat

tomcat-jsp-api org.apache.tomcat.embed

org.apache.tomcat.embed

org.apache.tomcat.embed

tomcat-embed-core tomcat-embed-el tomcat-embed-jasper

8.0.30

8.0.30

8.0.30

8.0.30

org.apache.tomcat.embed

tomcat-embed-loggingjuli org.apache.tomcat.embed

tomcat-embed-websocket

8.0.30

org.apache.velocity

velocity

1.7

org.apache.velocity

velocity-tools

2.0

Version

4.1.1

4.5.1

4.4.4

4.5.1

2.4.1

2.4.1

2.4.1

4.10.4

8.0.30

8.0.30

org.aspectj

org.aspectj

org.aspectj

org.codehaus.btm

org.codehaus.groovy

org.codehaus.groovy

org.codehaus.groovy

org.codehaus.groovy

org.codehaus.groovy

org.codehaus.groovy

org.codehaus.groovy

org.codehaus.groovy

org.codehaus.groovy

aspectjrt aspectjtools aspectjweaver btm groovy groovy-all groovy-ant groovy-bsf groovy-console groovy-docgenerator groovy-groovydoc groovy-groovysh groovy-jmx

2.4.4

2.4.4

2.4.4

2.4.4

2.4.4

2.4.4

2.4.4

1.8.7

1.8.7

1.8.7

2.1.4

2.4.4

2.4.4

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Group ID

org.codehaus.groovy

org.codehaus.groovy

org.codehaus.groovy

org.codehaus.groovy

org.codehaus.groovy

org.codehaus.groovy

org.codehaus.groovy

org.codehaus.groovy

org.codehaus.groovy

org.codehaus.groovy

org.codehaus.janino

org.crashub

org.crashub

org.crashub

org.crashub

org.crashub

org.crashub

org.crashub

org.eclipse.jetty

org.eclipse.jetty

org.eclipse.jetty

org.eclipse.jetty

org.eclipse.jetty

org.eclipse.jetty

org.eclipse.jetty

org.eclipse.jetty

org.eclipse.jetty

org.eclipse.jetty

org.eclipse.jetty

org.eclipse.jetty

Artifact ID

groovy-json groovy-jsr223 groovy-nio groovy-servlet groovy-sql groovy-swing groovy-templates groovy-test groovy-testng groovy-xml janino crash.cli

2.7.8

1.3.2

crash.connectors.ssh

1.3.2

crash.connectors.telnet

1.3.2

crash.embed.spring

crash.plugins.cron

crash.plugins.mail

1.3.2

1.3.2

1.3.2

2.4.4

2.4.4

2.4.4

2.4.4

2.4.4

2.4.4

2.4.4

Version

2.4.4

2.4.4

2.4.4

crash.shell

jetty-annotations jetty-continuation jetty-deploy jetty-http jetty-io jetty-jmx jetty-jsp jetty-plus jetty-security jetty-server jetty-servlet jetty-servlets

1.3.2

9.2.14.v20151106

9.2.14.v20151106

9.2.14.v20151106

9.2.14.v20151106

9.2.14.v20151106

9.2.14.v20151106

9.2.14.v20151106

9.2.14.v20151106

9.2.14.v20151106

9.2.14.v20151106

9.2.14.v20151106

9.2.14.v20151106

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Group ID

org.eclipse.jetty

org.eclipse.jetty

org.eclipse.jetty

org.eclipse.jetty.orbit

Artifact ID

jetty-util jetty-webapp jetty-xml javax.servlet.jsp

Version

9.2.14.v20151106

9.2.14.v20151106

9.2.14.v20151106

2.2.0.v201112011158

9.2.14.v20151106

impl org.elasticsearch

org.firebirdsql.jdbc

org.firebirdsql.jdbc

org.firebirdsql.jdbc

org.flywaydb

org.freemarker

org.glassfish

elasticsearch jaybird-jdk16 jaybird-jdk17 jaybird-jdk18 flyway-core freemarker javax.el

servlet

2.22.1

servlet-core org.glassfish.jersey.corejersey-server

2.22.1

org.glassfish.jersey.ext jersey-bean-validation

2.22.1

org.glassfish.jersey.ext jersey-spring3

2.22.1

2.22.1

jackson

9.2.14.v20151106

1.5.2

2.2.9

2.2.9

2.2.9

3.2.1

2.3.23

3.0.0

2.22.1

org.hamcrest

org.hamcrest

org.hibernate

org.hibernate

org.hibernate

org.hibernate

org.hibernate

org.hibernate

hamcrest-core hamcrest-library hibernate-core hibernate-ehcache

1.3

1.3

4.3.11.Final

4.3.11.Final

hibernate-entitymanager

4.3.11.Final

hibernate-envers

4.3.11.Final

hibernate-jpamodelgen hibernate-validator

4.3.11.Final

5.2.2.Final

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Group ID

org.hibernate

org.hornetq

org.hornetq

org.hsqldb

org.infinispan

org.infinispan

org.javassist

org.jboss.logging

org.jdom

org.jolokia

org.jooq

org.jooq

org.jooq

org.json

org.liquibase

org.mariadb.jdbc

org.mockito

org.mongodb

org.postgresql

org.skyscreamer

org.slf4j

org.slf4j

org.slf4j

org.slf4j

org.slf4j

org.slf4j

org.slf4j

org.spockframework

org.spockframework

org.springframework

Artifact ID

hibernate-validatorannotation-processor hornetq-jms-client hornetq-jms-server hsqldb infinispan-jcache infinispan-spring4 javassist jboss-logging jdom2 jolokia-core jooq jooq-codegen jooq-meta json liquibase-core mariadb-java-client mockito-core mongo-java-driver postgresql jsonassert jcl-over-slf4j jul-to-slf4j log4j-over-slf4j slf4j-api slf4j-jdk14 slf4j-log4j12 slf4j-simple spock-core spock-spring spring-aop

Version

5.2.2.Final

2.4.7.Final

2.4.7.Final

2.3.3

8.0.2.Final

8.0.2.Final

3.18.1-GA

3.3.0.Final

2.0.6

1.3.2

3.7.1

3.7.1

3.7.1

20140107

3.4.2

1.2.3

1.10.19

2.13.3

9.4-1206-jdbc41

1.2.3

1.7.13

1.7.13

1.7.13

1.7.13

1.7.13

1.7.13

1.7.13

1.0-groovy-2.4

1.0-groovy-2.4

4.2.4.RELEASE

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Group ID

org.springframework

org.springframework

org.springframework

org.springframework

org.springframework

org.springframework

org.springframework

org.springframework

org.springframework

org.springframework

org.springframework

org.springframework

org.springframework

org.springframework

org.springframework

org.springframework

org.springframework

org.springframework

org.springframework

org.springframework

Artifact ID

spring-aspects spring-beans spring-context spring-jdbc spring-jms

Version

4.2.4.RELEASE

4.2.4.RELEASE

4.2.4.RELEASE

spring-context-support

4.2.4.RELEASE

spring-core

4.2.4.RELEASE

spring-expression spring-instrument spring-instrumenttomcat

4.2.4.RELEASE

4.2.4.RELEASE

4.2.4.RELEASE

4.2.4.RELEASE

4.2.4.RELEASE

springloaded spring-messaging spring-orm spring-oxm spring-test spring-tx spring-web spring-webmvc spring-webmvc-portlet spring-websocket org.springframework.amqp spring-amqp org.springframework.amqp spring-rabbit org.springframework.batchspring-batch-core org.springframework.batchspring-batchinfrastructure

1.2.5.RELEASE

4.2.4.RELEASE

4.2.4.RELEASE

4.2.4.RELEASE

4.2.4.RELEASE

4.2.4.RELEASE

4.2.4.RELEASE

4.2.4.RELEASE

4.2.4.RELEASE

4.2.4.RELEASE

1.5.2.RELEASE

1.5.2.RELEASE

3.0.6.RELEASE

3.0.6.RELEASE

org.springframework.batchspring-batchintegration

3.0.6.RELEASE

org.springframework.batchspring-batch-test org.springframework.boot spring-boot org.springframework.boot spring-boot

3.0.6.RELEASE

1.3.1.BUILD-SNAPSHOT

1.3.1.BUILD-SNAPSHOT

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Group ID Artifact ID

org.springframework.boot spring-boot-actuator

Version

1.3.1.BUILD-SNAPSHOT

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-actuatordocs org.springframework.boot spring-bootautoconfigure org.springframework.boot spring-boot-devtools org.springframework.boot spring-boot-loader org.springframework.boot spring-boot-loadertools

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-bootconfiguration-metadata

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-bootconfiguration-processor

1.3.1.BUILD-SNAPSHOT

1.3.1.BUILD-SNAPSHOT

1.3.1.BUILD-SNAPSHOT

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-starter

1.3.1.BUILD-SNAPSHOT

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-starteractuator org.springframework.boot spring-boot-starteramqp org.springframework.boot spring-boot-starterbatch

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-starter-aop

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-starterartemis

1.3.1.BUILD-SNAPSHOT

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-startercache

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-startercloud-connectors

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-starterdata-cassandra

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-starterdata-elasticsearch

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-starterdata-gemfire

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-starterdata-jpa

1.3.1.BUILD-SNAPSHOT

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Group ID Artifact ID

org.springframework.boot spring-boot-starterdata-mongodb org.springframework.boot spring-boot-starterdata-rest org.springframework.boot spring-boot-starterdata-solr org.springframework.boot spring-boot-starterfreemarker org.springframework.boot spring-boot-startergroovy-templates org.springframework.boot spring-boot-starterhateoas org.springframework.boot spring-boot-starterhornetq org.springframework.boot spring-boot-starterintegration org.springframework.boot spring-boot-starterjdbc org.springframework.boot spring-boot-starterjersey org.springframework.boot spring-boot-starterjetty org.springframework.boot spring-boot-starterjooq org.springframework.boot spring-boot-starterjta-atomikos org.springframework.boot spring-boot-starterjta-bitronix org.springframework.boot spring-boot-starterlog4j org.springframework.boot spring-boot-starterlog4j2 org.springframework.boot spring-boot-starterlogging org.springframework.boot spring-boot-startermail

Version

1.3.1.BUILD-SNAPSHOT

1.3.1.BUILD-SNAPSHOT

1.3.1.BUILD-SNAPSHOT

1.3.1.BUILD-SNAPSHOT

1.3.1.BUILD-SNAPSHOT

1.3.1.BUILD-SNAPSHOT

1.3.1.BUILD-SNAPSHOT

1.3.1.BUILD-SNAPSHOT

1.3.1.BUILD-SNAPSHOT

1.3.1.BUILD-SNAPSHOT

1.3.1.BUILD-SNAPSHOT

1.3.1.BUILD-SNAPSHOT

1.3.1.BUILD-SNAPSHOT

1.3.1.BUILD-SNAPSHOT

1.3.1.BUILD-SNAPSHOT

1.3.1.BUILD-SNAPSHOT

1.3.1.BUILD-SNAPSHOT

1.3.1.BUILD-SNAPSHOT

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Spring Boot Reference Guide

Group ID Artifact ID

org.springframework.boot spring-boot-startermobile

Version

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-startermustache

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-starterredis

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-starterremote-shell

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-startersecurity

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-startersocial-facebook

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-startersocial-linkedin

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-startersocial-twitter

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-startertest

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-starterthymeleaf

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-startertomcat

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-starterundertow

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-startervalidation org.springframework.cloudspring-cloud-core

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-startervelocity org.springframework.cloudspring-cloudcloudfoundry-connector

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-starter-web

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-starterwebsocket

1.3.1.BUILD-SNAPSHOT org.springframework.boot spring-boot-starter-ws

1.3.1.BUILD-SNAPSHOT

1.2.1.RELEASE

1.2.1.RELEASE

1.3.1.BUILD-SNAPSHOT Spring Boot 283

Spring Boot Reference Guide

Group ID Artifact ID

org.springframework.cloudspring-cloud-herokuconnector

Version

1.2.1.RELEASE

org.springframework.cloudspring-cloudlocalconfig-connector

1.2.1.RELEASE

org.springframework.cloudspring-cloud-springservice-connector

1.2.1.RELEASE

org.springframework.data spring-cql org.springframework.data spring-data-cassandra org.springframework.data spring-data-commons org.springframework.data spring-data-couchbase

1.3.1.RELEASE

1.3.1.RELEASE

1.11.1.RELEASE

1.4.1.RELEASE

1.3.1.RELEASE

org.springframework.data spring-dataelasticsearch org.springframework.data spring-data-gemfire org.springframework.data spring-data-jpa org.springframework.data spring-data-keyvalue org.springframework.data spring-data-mongodb

1.7.1.RELEASE

1.9.1.RELEASE

1.0.1.RELEASE

1.8.1.RELEASE

1.8.1.RELEASE

org.springframework.data spring-data-mongodbcross-store org.springframework.data spring-data-mongodblog4j

1.8.1.RELEASE

org.springframework.data spring-data-neo4j org.springframework.data spring-data-redis org.springframework.data spring-data-rest-core

3.4.1.RELEASE

1.6.1.RELEASE

2.4.1.RELEASE

2.4.1.RELEASE

org.springframework.data spring-data-rest-halbrowser org.springframework.data spring-data-rest-webmvc

2.4.1.RELEASE

org.springframework.data spring-data-solr

1.5.1.RELEASE

0.19.0.RELEASE

org.springframework.integration

4.2.4.RELEASE

org.springframework.integration

4.2.4.RELEASE

4.2.4.RELEASE

event org.springframework.integration

4.2.4.RELEASE

1.3.1.BUILD-SNAPSHOT Spring Boot 284

Spring Boot Reference Guide

Group ID Artifact ID Version

org.springframework.integration

4.2.4.RELEASE

org.springframework.integration

4.2.4.RELEASE

4.2.4.RELEASE

gemfire

4.2.4.RELEASE

groovy org.springframework.integration

4.2.4.RELEASE

4.2.4.RELEASE

org.springframework.integration

4.2.4.RELEASE

org.springframework.integration

4.2.4.RELEASE

org.springframework.integration

4.2.4.RELEASE

org.springframework.integration

4.2.4.RELEASE

org.springframework.integration

4.2.4.RELEASE

4.2.4.RELEASE

mongodb org.springframework.integration

4.2.4.RELEASE

4.2.4.RELEASE

redis org.springframework.integration

4.2.4.RELEASE

4.2.4.RELEASE

scripting

4.2.4.RELEASE

security org.springframework.integration

4.2.4.RELEASE

4.2.4.RELEASE

stomp

4.2.4.RELEASE

stream

4.2.4.RELEASE

syslog org.springframework.integration

4.2.4.RELEASE

4.2.4.RELEASE

twitter

1.3.1.BUILD-SNAPSHOT Spring Boot 285

Spring Boot Reference Guide

Group ID Artifact ID Version

4.2.4.RELEASE

websocket

4.2.4.RELEASE

org.springframework.integration

4.2.4.RELEASE

org.springframework.integration

4.2.4.RELEASE

4.2.4.RELEASE

zookeeper

1.1.5.RELEASE

1.2.0.RELEASE

org.springframework.retryspring-retry

1.0.1.RELEASE

org.springframework.restdocs

1.0.1.RELEASE

1.1.2.RELEASE

4.0.3.RELEASE

org.springframework.security

4.0.3.RELEASE

4.0.3.RELEASE

org.springframework.security

4.0.3.RELEASE

4.0.3.RELEASE

org.springframework.security

4.0.3.RELEASE

4.0.3.RELEASE

1.0.3.RELEASE

4.0.3.RELEASE

4.0.3.RELEASE

messaging org.springframework.security

4.0.3.RELEASE

4.0.3.RELEASE

remoting org.springframework.security

4.0.3.RELEASE

4.0.3.RELEASE

4.0.3.RELEASE

2.0.8.RELEASE

org.springframework.security.oauth

2.0.8.RELEASE

1.0.2.RELEASE

1.3.1.BUILD-SNAPSHOT Spring Boot 286

Spring Boot Reference Guide

Group ID Artifact ID Version

1.0.2.RELEASE

redis

1.1.4.RELEASE

1.1.4.RELEASE

org.springframework.social

2.0.3.RELEASE

2.0.3.RELEASE

web org.springframework.social

1.0.2.RELEASE

org.springframework.social

1.1.4.RELEASE

org.springframework.ws

spring-ws-core

1.1.2.RELEASE

1.1.4.RELEASE

2.2.3.RELEASE

org.springframework.ws

org.springframework.ws

org.springframework.ws

org.thymeleaf

org.thymeleaf

org.thymeleaf.extras

spring-ws-security spring-ws-support spring-ws-test thymeleaf thymeleaf-spring4 thymeleaf-extrasconditionalcomments

2.2.3.RELEASE

2.2.3.RELEASE

2.2.3.RELEASE

2.1.4.RELEASE

2.1.4.RELEASE

2.1.1.RELEASE

org.thymeleaf.extras

thymeleaf-extrasspringsecurity4

2.1.2.RELEASE

org.webjars

org.webjars

org.yaml

redis.clients

wsdl4j hal-browser webjars-locator snakeyaml jedis wsdl4j

9f96c74

0.28

1.16

2.7.3

1.6.3

1.3.1.BUILD-SNAPSHOT Spring Boot 287

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