java 自定义 annotation

package myanno;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface MyAutoValue {
    public String value() default "";
}

package myanno;

import java.lang.annotation.Annotation;
import java.lang.reflect.Field;

public class Test {
    
    @MyAutoValue("hello world")
    public static String value;
    
    public static void main(String args[]) throws ClassNotFoundException, NoSuchFieldException, SecurityException{
        Class clazz = Class.forName("myanno.Test");
        Field field = clazz.getField("value");
        Annotation[] ans = field.getAnnotations();
        System.out.println(((MyAutoValue) ans[0]).value());
    }
}