java元注解@Inherited的使用详解

/**
 * Indicates that an annotation type is automatically inherited. If
 * an Inherited meta-annotation is present on an annotation type
 * declaration, and the user queries the annotation type on a class
 * declaration, and the class declaration has no annotation for this type,
 * then the class's superclass will automatically be queried for the
 * annotation type. This process will be repeated until an annotation for this
 * type is found, or the top of the class hierarchy (Object)
 * is reached. If no superclass has an annotation for this type, then
 * the query will indicate that the class in question has no such annotation.
 *
 * <p>Note that this meta-annotation type has no effect if the annotated
 * type is used to annotate anything other than a class. Note also
 * that this meta-annotation only causes annotations to be inherited
 * from superclasses; annotations on implemented interfaces have no
 * effect.
 *
 * @author Joshua Bloch
 * @since 1.5
 * @jls 9.6.3.3 @Inherited
 */
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.ANNOTATION_TYPE)
public @interface Inherited {
}

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Inherited
public @interface InheritedTest {

  String value();
}

@InheritedTest("拥有Inherited")
public class Person {


  public void method(){
  }


  public void method2(){
  }
}

public class Student extends Person {
}

public class TestInherited {


  public static void main(String[] args) {
    Class<Student> studentClass = Student.class;
    if (studentClass.isAnnotationPresent(InheritedTest.class)){
      System.out.println(studentClass.getAnnotation(InheritedTest.class).value());
    }


  }
}

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface IsNotInherited {
  String value();
}

@IsNotInherited("未拥有Inherited")
public class Person {


  public void method(){
  }


  public void method2(){
  }
}

public class Student extends Person {
}

public class TestInherited {


  public static void main(String[] args) {
    Class<Student> studentClass = Student.class;
    if (studentClass.isAnnotationPresent(IsNotInherited.class)){
      System.out.println(studentClass.getAnnotation(IsNotInherited.class).value());
    }


  }
}