动态代理

接口

public interface ContactDAO { public void save(); } 

 

接口实现

 

public class ContactDAOImpl implements ContactDAO { @Override public void save() { System.out.println("save start!"); } } 

 

Server

public class ContactService { public void test(){ ContactDAO cdao = new ContactDAOImpl(); cdao.save(); } } 

 

代理类

 

 

import java.lang.reflect.InvocationHandler; import java.lang.reflect.Method; public class ActiveProxy implements InvocationHandler { private Object target; public Object getTarget() { return target; } public void setTarget(Object target) { this.target = target; } public void beforeSave(){ System.out.println("before save!"); } @Override public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { beforeSave(); method.invoke(target, args); return null; } } 

 

//method.invoke(被代理的方法，参数)

 

测试类

import java.lang.reflect.Proxy; import org.junit.Test; public class ContactServiceTest { @Test public void testProxy(){ ContactDAO cdao = new ContactDAOImpl(); ActiveProxy apro = new ActiveProxy(); apro.setTarget(cdao); ContactDAO conDaoProxy = (ContactDAO)Proxy.newProxyInstance(cdao.getClass().getClassLoader(), new Class[]{ContactDAO.class}, apro); conDaoProxy.save(); } } 

 

//Proxy.newProxyInstance("产生代理的类"，"代理对象的实现的接口"，"处理的Handler")