Question

我有一个定义如下的注释：

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

}

我正在使用它：

@Retriable
interface MyInterface {
    public void myMethod();
}

现在，我有第二个接口，它扩展了第一个接口：

interface MySecondInterface extends MyInterface {

}

我想为MySecondInterface获取所有注释，这意味着我还希望获得在超级接口上定义的注释。 / p>

我尝试了什么：

Class clazz = MySecondInterface.class;

Retriable annotation = clazz.getAnnotation(Retriable.class);
System.out.println("Retriable annotation: " + annotation);

Annotation[] annotations = clazz.getAnnotations();
System.out.println("Annotations: " + Arrays.toString(annotations));

annotations = clazz.getDeclaredAnnotations();
System.out.println("Declared Annotations: " + Arrays.toString(annotations));

结果是：

Retriable annotation: null
Annotations: []
Declared Annotations: []

在所有情况下，它都找不到从Retriable继承的MyInterface注释。（DEMO）

有没有办法让它识别超级界面的注释？

Answer 1

来自java.lang.annotation.Inherited的javadoc：

    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.

所以改变接口到类。它会影响

@Retriable
class MyClass {
    public void myMethod(){

    }
}

class MySecondClass extends MyClass {

}

Class.getAnnotations（）/ getDeclaredAnnotations（）为子类返回空数组

1 个答案: