Java 基于接口的动态代理

UserDao接口

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package com.pry.cn;   public interface UserDao {     public int add(int a,int b);     public String update(String id); }

　　

UserDao实现类

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package com.pry.cn;   public class UserDaoImpl implements UserDao {     @Override     public int add(int a, int b) {         System.out.println("add方法执行了");         return a + b;     }       @Override     public String update(String id) {         System.out.println("update方法执行了");         return id;     } }

　　

代理实现方法

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class UserDaoProxy implements InvocationHandler {     private Object obj;       public UserDaoProxy(Object obj) {         this.obj = obj;     }       @Override     public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {         System.out.println("增强方法执行前:" + method.getName() + "参数:" + Arrays.toString(args));         Object res = method.invoke(obj, args);         System.out.println("增强方法执行后:" + obj);         return res;     } }

　　

执行对象

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public class MainRum {     public static void main(String[] args) {         Class[] interfaces = {UserDao.class};         UserDaoImpl userDao = new UserDaoImpl();         UserDao dao = (UserDao) Proxy.newProxyInstance(MainRum.class.getClassLoader(), interfaces, new UserDaoProxy(userDao));         dao.add(2, 6);     } }

　　

输出结果

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增强方法执行前:add参数:[2, 6] add方法执行了 增强方法执行后:com.pry.cn.UserDaoImpl@2503dbd3