Spring-boot Notes I

1. 1. Developer Tools
   1. 1.1. Automatic Restart
   2. 1.2. Note

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.

Maven configuration, in pom.xml,

<dependencies>
	<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-devtools</artifactId>
		<optional>true</optional>
	</dependency>
</dependencies>

Automatic Restart

Applications that use spring-boot-devtools automatically restart whenever files on the classpath change. Note that certain resources, such as static assets and view templates, do not need to restart the application.

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 causes the classpath to be updated and triggers a restart. In IntelliJ IDEA, building the project (Build -> Build Project) has the same effect.

Logging changes in condition evaluation

By default, each time your application restarts, a report showing the condition evaluation delta is logged. The report shows the changes to your application’s auto-configuration as you make changes such as adding or removing beans and setting configuration properties.

To disable the logging of the report, set the following property:

spring.devtools.restart.log-condition-evaluation-delta=false

Excluding Resources

Certain resources do not necessarily need to trigger a restart when they are changed. For example, Thymeleaf templates can be edited in-place. By default, changing resources in /META-INF/maven, /META-INF/resources, /resources, or /templates does not trigger a restart but does 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 property:

spring.devtools.restart.exclude=static/**,public/**

Note

Found something interesting that needs to figure it out later. When a project consists of a few modules, e.g., module B depends on module A, where B has main() function. Build a project (Auto-start) only has good effects on changes in module B, while not always applies to module A. Just a remark here.

Refer Spring-boot Developer Tools for more details.