package com.czp.util;import java.lang.reflect.InvocationHandler;import java.lang.reflect.Method;import java.lang.reflect.Proxy;/** * 代理生成工厂,要求其子类实现before(...),after(...),onException(...) 实现处理业务 * * @author caozhongping * */public abstract class ProxyFacty<T> implements InvocationHandler {private T target;public ProxyFacty(T target) {super();this.target = target;}/** * 创建代理，如果目标类没有实现接口则返回自己 * * @param target * @return */@SuppressWarnings("unchecked")public T getProxy() {Class<T> cls = (Class<T>) target.getClass();if (cls.getInterfaces() != null) {return (T) Proxy.newProxyInstance(cls.getClassLoader(),cls.getInterfaces(), this);}return target;}/*** * 通过代理实现调用 */@Overridepublic Object invoke(Object proxy, Method method, Object[] args)throws Throwable {Object obj = null;try {before(args);obj = method.invoke(target, args);after(args);} catch (Exception e) {onException(e);}return obj;}/*** * 出现异常时处理 * * @param ex */public abstract void onException(Exception ex);/** * 调用方法后处理 * * @param args */public abstract void after(Object[] args);/** * 调用方法前处理 * * @param args */public abstract void before(Object[] args);}//目标对象的接口package com.czp.util;public interface TestItf {void say(String name)throws Exception;}//目标对象package com.czp.util;public class TestItfImpl implements TestItf {@Overridepublic void say(String name) throws Exception {if(name==null)throw new Exception("name is null");System.out.println("Hell, "+name);}}//代理工具类，继承工厂类实现拦截package com.czp.util;public class ProxyUtil<T> extends ProxyFacty<T>{public ProxyUtil(T target) {super(target);}@Overridepublic void onException(Exception ex) {System.out.println("call Method error:"+ex);}@Overridepublic void after(Object[] args) {System.out.println("----------exit method-----------");}@Overridepublic void before(Object[] args) {System.out.println("-----Enter method------");} public static void main(String[] args) throws Exception { TestItf target = new TestItfImpl();//目标对象TestItf proxy = new ProxyUtil<TestItf>(target).getProxy();//目标的代理实例proxy.say("WengJiaBao");//正常调用//异常调用proxy.say(null);}}//输出：-----Enter method------Hell, WengJiaBao----------exit method----------------Enter method------call Method error:java.lang.reflect.InvocationTargetException
