获取带注释的字段变量的额外信息

Question

I have a class which has some properties and they are annotated with one custom annotation, and I want its information in another class.

How to create retrieve the annotation instance and how to get its extra info?

My source code:

/**custom annotation **/

public @interface Info {
    public String name();
}

/**class where i used custom annotation **/

class ABC {
@Info(name="Institution Name")
    private String Name;
}

Answer 1

You need to make your annotation with retention policy RetentionPolicy.RUNTIME in order to be able to acceed to your annotation on RUNTIME.

@Retention(RetentionPolicy.RUNTIME)
public @interface Info {
    public String name();
}

After that you have to use this.getClass().getDeclaredField("name") in order to get your field.You can get your annotation with getAnnotation(Info.class) method. You will get an instance of your annotation and you will be able to acceed to its information.

https://docs.oracle.com/javase/8/docs/api/java/lang/Class.html#getDeclaredField-java.lang.String- https://docs.oracle.com/javase/8/docs/api/java/lang/Class.html#getAnnotation-java.lang.Class-