java：spring【AnnotationMetadata】的简单使用例子

# 项目代码资源：

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https://download.csdn.net/download/chenhz2284/89435385

# 项目代码

【pom.xml】

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
    <version>2.3.12.RELEASE</version>
</dependency>
<dependency>
    <groupId>ch.qos.logback</groupId>
    <artifactId>logback-classic</artifactId>
    <version>1.2.11</version>
</dependency>

【application.properties】

server.port=8080
spring.application.name=myBeanMain

management.server.port=7001
management.endpoints.web.exposure.include=*

【Annotation1.java】

package com.chz.myBeanMain.annotations;

@Target({ElementType.TYPE, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
public @interface Annotation1 {

    String name() default "Annotation1-name";
    String p1() default "Annotation1-p1";
}

【Annotation2.java】

package com.chz.myBeanMain.annotations;

@Target({ElementType.TYPE, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@Annotation1(name = "at Annotation2: Annotation1-name")
public @interface Annotation2 {

    String name() default "Annotation2-name";

}

【Annotation3.java】

package com.chz.myBeanMain.annotations;

@Target({ElementType.TYPE, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
public @interface Annotation3 {

    String name() default "Annotation2-name";
}

【BranchCommonImportSelector.java】

package com.chz.myBeanMain.imports.importSelector;

@Slf4j
public class BranchCommonImportSelector implements ImportSelector
{
    @Override
    public String[] selectImports(AnnotationMetadata annotationMetadata)
    {
        log.info("chz >>> BranchCommonImportSelector.selectImports()");
        MyBeanMainTest2.test(annotationMetadata);
        return new String[]{};
    }
}

【MyBeanMainTest.java】

package com.chz.myBeanMain;

@Annotation1(name = "at MyBeanMainTest: Annotation1-name")
@Annotation2(name = "at MyBeanMainTest: Annotation2-name")
@Import(BranchCommonImportSelector.class)
@SpringBootApplication
public class MyBeanMainTest {

    @Annotation1(name = "at main() method")
    public static void main(String[] args) {
        SpringApplication.run(MyBeanMainTest.class, args);
    }

    @Annotation1(name = "at test1() method")
    public static void test1()
    {
    }

    @Annotation2(name = "at test2() method")
    public static void test2()
    {
    }

    @Annotation3(name = "at test3() method")
    public static void test3()
    {
    }
}

【MyBeanMainTest2.java】

package com.chz.myBeanMain;

public class MyBeanMainTest2 {

    public static void main(String[] args) throws Exception
    {
        // 生成【MyBeanMainTest.class】的【AnnotationMetadata】
        AnnotationMetadata annotationMetadata = AnnotationMetadata.introspect(MyBeanMainTest.class);
        MyBeanMainTest2.test(annotationMetadata);
    }

    public static void test(AnnotationMetadata annotationMetadata)
    {
        StandardAnnotationMetadata standardAnnotationMetadata = (StandardAnnotationMetadata)annotationMetadata;

        // 获取注解【Annotation1】的所有属性值
        System.out.println("################################################################");
        Map<String, Object> annotationAttributes = standardAnnotationMetadata.getAnnotationAttributes(Annotation1.class.getName(), false);
        System.out.println(annotationAttributes);

        // 合并所有的注解
        MergedAnnotations mergedAnnotations = standardAnnotationMetadata.getAnnotations();

        // 获取注解【Annotation1】上的【name】属性值
        System.out.println("################################################################");
        MergedAnnotation<Annotation1> annotation1MergedAnnotation = mergedAnnotations.get(Annotation1.class);
        String name = annotation1MergedAnnotation.getString("name");
        System.out.println(name);

        // 获取主程序类的所有注解名(去重)
        System.out.println("################################################################");
        Set<String> annotationTypes = standardAnnotationMetadata.getAnnotationTypes();
        System.out.println(annotationTypes);

        // 列出【MyBeanMainTest】类的所有注解，包括注解的注解
        System.out.println("################################################################");
        for( MergedAnnotation<Annotation> mergedAnnotation : mergedAnnotations ){
            System.out.println(mergedAnnotation.getType());
        }

        // 获取被【Annotation1】注解的所有方法
        System.out.println("################################################################");
        Set<MethodMetadata> annotatedMethods = standardAnnotationMetadata.getAnnotatedMethods(Annotation1.class.getName());
        for( MethodMetadata methodMetadata : annotatedMethods ){
            System.out.println("-----------------------");
            System.out.println(methodMetadata.getMethodName());
            System.out.println(methodMetadata.getAnnotationAttributes(Annotation1.class.getName()));
        }
    }
}