How to get other annotations of class mark annotation combination in java

1: Define annotation A

@Retention(RetentionPolicy.RUNTIME)
public @interface A {
    
    
}

2: Define annotation B and use annotation A annotation

@A
@Retention(RetentionPolicy.RUNTIME)
public @interface B {
    
    
    
}

3: Define the class and use the annotation B annotation

@B
public class Cls {
    
    
}

4: Get all the annotations of the Cls class

public class Main {
    
    

    public static void main(String[] args) {
    
    
        // 首先直接获取B注解，这是确定的
        B annotationB = Cls.class.getAnnotation(B.class);
        System.out.println("annotationB: ");
        System.out.println(annotationB);

        // 通过B的class获取注解A,这里注意使用annotationType()方法，而不是getClass()
        // 因为此时返回的是代理对象class，而非本class
        A annotationA = annotationB.annotationType().getAnnotation(A.class);
        System.out.println("annotationA: ");
        System.out.println(annotationA);
    }
}

Perform the test:

annotationB: 
@compositeannotation.B()
annotationA: 
@compositeannotation.A()