package com.sam.annotation;
import java.lang.annotation.*;
/**
* @author sam
* @since 2017/7/13
*/
@Target({ElementType.METHOD, ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
@Inherited
@Documented
public @interface MyMessage {
String name() default "sam";
int num() default 0;
String desc();
}
package com.sam.annotation;
/**
* @author sam
* @since 2017/7/13
*/
public class AnnotationTest {
@MyMessage(num = 10, desc = "参数a")
private static int a;
@MyMessage(name = "Sam test", desc = "测试方法test")
public void test() {
System.out.println("test");
}
}
package com.sam.annotation;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
/**
* 使用反射处理注解
*
* @author sam
* @since 2017/7/13
*/
public class MyMessageProcessor {
public static void main(String[] args) {
try {
//加载annotationTest.class类
Class clazz = MyMessageProcessor.class.getClassLoader().loadClass("com.sam.annotation.AnnotationTest");
//获取属性
Field[] fields = clazz.getDeclaredFields();
//遍历属性
for (Field field : fields) {
MyMessage myMessage = field.getAnnotation(MyMessage.class);
System.out.println("name:" + myMessage.name() + " num:" + myMessage.num() + " desc:" + myMessage.desc());
}
//获取类中的方法
Method[] methods = clazz.getMethods();
//遍历方法
for (Method method : methods) {
//判断方法是否带有MyMessage注解
if (method.isAnnotationPresent(MyMessage.class)) {
// 获取所有注解 method.getDeclaredAnnotations();
// 获取MyMessage注解
MyMessage myMessage = method.getAnnotation(MyMessage.class);
System.out.println("name:" + myMessage.name() + " num:" + myMessage.num() + " desc:" + myMessage.desc());
}
}
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
}
name:sam num:10 desc:参数a
name:Sam test num:0 desc:测试方法test
Process finished with exit code 0