注解入门实例

package com.csair.anto;

import java.lang.reflect.Method;

public class RunAnto {
		/*
		 * 被注解的三个方法
		 */
		@Student(userName = "william", address = "广东省东莞市")
		public void method_1() {
		}

		@Student(userName = "媛媛", address = "")
		public void method_2() {
		}

		@Student(address = "北京市")
		public void method_3() {
		}

		/*
		 * 解析注解，将RunAnto类 所有被注解方法 的信息打印出来
		 */
		public static void main(String[] args) {
			Method[] methods = RunAnto.class.getDeclaredMethods();
			for(Method method : methods){
				boolean hasAnnotation = method.isAnnotationPresent(Student.class);
				if(hasAnnotation){
					Student annotation = method.getAnnotation(Student.class);
					System.out.println(method.getName() + " " + annotation.userName() + " " +annotation.address());
				}
			}
		}
}                                                                                      

	
	

package com.csair.anto;

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

@Target(ElementType.METHOD)   
@Retention(RetentionPolicy.RUNTIME)   
@Documented  
@Inherited  
public @interface Student {
	String userName() default "admin";
	String address();
}