JDK中的Proxy技术实现AOP功能

最新推荐文章于 2023-03-02 06:45:00 发布

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本文介绍如何使用Java的JDK动态代理技术实现面向切面编程(AOP)。通过创建JDKProxyFactory实例，为指定的目标对象生成代理对象，并在调用目标方法前后加入自定义的行为。

package com.saly.jdk.aop;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

public class JDKProxyFactory implements InvocationHandler{
   private Object targetObject;
   //代理对象
   public Object createProxyIntance(Object targetObject){
       this.targetObject = targetObject;
       return Proxy.newProxyInstance(this.targetObject.getClass().getClassLoader(),
               this.targetObject.getClass().getInterfaces(),this);

   }
   @Override
   public Object invoke(Object proxy, Method method, Object[] args)
           throws Throwable {
       PersonServiceBean bean = (PersonServiceBean) this.targetObject;
       Object result = null;
       if(bean.getUser()!=null){
           //advice()-->前置通知
           try {
               method.invoke(targetObject, args);
           //afteradvice()-->后置通知
           } catch (Exception e) {
               //exceptionadvice()-->例外通知
           }finally{
               //finallyadvice()-->最终通知
           }
       }
       return result;
   }

}

public interface PersonService {
   public void save(String name);
   public void update(String name,Integer personId);
   public String getPersonName(Integer personId);
}

public class PersonServiceBean implements PersonService {

   private String user = null;

   public PersonServiceBean(){
   }
   public String getUser() {
       return user;
   }
   public PersonServiceBean(String user){
       this.user = user;
   }
   @Override
   public String getPersonName(Integer personId) {
       System.out.println("我是 getPersonName方法");
       return "salyfan";
   }
   @Override
   public void save(String name) {
       System.out.println("我是save()方法");
   }

   @Override
   public void update(String name, Integer personId) {
       System.out.println("我是update()方法");
   }

}

@Test
   public void aopJDKProxyFactory(){
       JDKProxyFactory factory = new JDKProxyFactory();

       PersonService service = (PersonService) factory.createProxyIntance(new PersonServiceBean(""));
       service.getPersonName(2);
   }