springboot配置类智能提示

springboot配置类智能提示

实践环境

• windows10
• gradle-4.8.1
• IDEA2017.1.2
• springboot:2.0.6.RELEASE

实现过程

• 我们在使用springboot的相关依赖时经常可以在配置文件（application.yml）中得到智能提示
• 下面我们自己也来研究一番
• 一般我们都会写一个配置类，如下

@ConfigurationProperties("example.service")
public class ExampleProperties {
    private String prefix="111";
    private String suffix="222";
  	//省略getter,setter
}

• 然后在配置文件中使用

example:
  service:
    prefix: 111
    suffix: 222

• 可是这样IDEA没有任何提示，按住ctrl也无法跳转到类定义的地方
• 首先，按照官方文档的做法https://docs.spring.io/spring-boot/docs/2.0.6.RELEASE/reference/html/configuration-metadata.html#configuration-metadata-annotation-processor，我把部分说明原封不动拷过来了

B.3 Generating Your Own Metadata by Using the Annotation Processor
You can easily generate your own configuration metadata 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, include a dependency on spring-boot-configuration-processor.

With Maven the dependency should be declared as optional, as shown in the following example:


	org.springframework.boot
	spring-boot-configuration-processor
	true

With Gradle 4.5 and earlier, the dependency should be declared in the compileOnly configuration, as shown in the following example:

dependencies {
	compileOnly "org.springframework.boot:spring-boot-configuration-processor"
}
With Gradle 4.6 and later, the dependency should be declared in the annotationProcessor configuration, as shown in the following example:

dependencies {
	annotationProcessor "org.springframework.boot:spring-boot-configuration-processor"
}
If you are using an additional-spring-configuration-metadata.json file, the compileJava task should be configured to depend on the processResources task, as shown in the following example:

compileJava.dependsOn(processResources)
This dependency ensures that the additional metadata is available when the annotation processor runs during compilation.

The processor picks up both classes and methods that are annotated with @ConfigurationProperties. The Javadoc for field values within configuration classes is used to populate the description attribute.

• 由于我使用的是gradle4.8,因此按照官方的说法使用annotationProcessor，然后在resources/META-INF目录下新建了additional-spring-configuration-metadata.json

{
  "properties": [
    {
      "sourceType": "com.example.examplespringbootstarter.bean.config.ExampleProperties",
      "name": "example.service.prefix",
      "type": "java.lang.String",
      "description": "Description for example.service.prefix."
    },
    {
      "sourceType": "com.example.examplespringbootstarter.bean.config.ExampleProperties",
      "name": "example.service.enable",
      "type": "java.lang.String",
      "description": "Description for example.service.enable."
    },
    {
      "sourceType": "com.example.examplespringbootstarter.bean.config.ExampleProperties",
      "name": "example.service.suffix",
      "type": "java.lang.String",
      "description": "Description for example.service.suffix."
    }
  ] }

• 注意不能使用中文，否则会有乱码，这个问题还没找到解决办法，如有人知道，请不吝赐教。
• 此时打开此json文件就会看到IDEA上这个红色的错误提示

• 出现这个错误的话那么配置文件是无法提示的，这个错误也暂时找不到解决办法。
• 于是将之前的annotationProcessor 改为compileOnly后，这个红色的错误消失，发现智能提示也有了。突然一脸懵逼，官网你写的到底正不正确啊，是不是我打开的方式不对啊？（总之，这里经过实践就不要照着官网的了）
• 如果发现还是无效的话那么请在项目目录下执行命令：gradlew assemble， 或者如图双击assemble

参考

https://docs.spring.io/spring-boot/docs/2.0.5.RELEASE/reference/html/configuration-metadata.html#configuration-metadata-annotation-processor

https://blog.csdn.net/L_Sail/article/details/70342023