获取与注释字段列表，利用反射 [英] Get list of fields with annotation, by using reflection

问题描述

创建我的注释

public @interface MyAnnotation {
}

我把它放在场在我的测试对象

I put it on fields in my test object

public class TestObject {

    @MyAnnotation 
    final private Outlook outlook;
    @MyAnnotation 
    final private Temperature temperature;
     ...
}

现在我想要得到的所有字段列表以 MyAnnotation 。

Now I want to get list of all fields with MyAnnotation.

for(Field field  : TestObject.class.getDeclaredFields())
{
    if (field.isAnnotationPresent(MyAnnotation.class))
        {
              //do action
        }
}

但好像我做块从不执行行动和领域没有任何标注如下code返回0。

But seems like my block do action is never executed, and fields has no annotation as the following code returns 0.

TestObject.class.getDeclaredField("outlook").getAnnotations().length;

是任何人都可以帮助我，告诉我什么，我做错了什么？

Is anyone can help me and tell me what i'm doing wrong?

推荐答案

您需要标记注释为是在运行时可用。以下添加到您的注释code。

You need to mark the annotation as being available at runtime. Add the following to your annotation code.

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

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