设计模式（十）代理模式

代理：只需要对象进行相关的操作，对象操作的前后的处理的行为人，即是代理。

代码之静态代理：

球员相关工作的接口：

public interface PlayerInterface {//踢球，球员本身的技能public void playFootBall();//下面为经纪人(代理的工作)public void chooseFootBallTeam();public void getAdvertisement();}

球员类实现其接口：

public class FootBallPlayer implements PlayerInterface{@Overridepublic void playFootBall() {System.out.println("驰骋足坛");}@Overridepublic void chooseFootBallTeam() {System.out.println("选择伟大的俱乐部发展");}@Overridepublic void getAdvertisement() {System.out.println("代言广告");}}

球员经纪人(代理)类实现接口：

public class PlayerProxy implements PlayerInterface{public PlayerProxy(PlayerInterface playerInterface) {super();this.playerInterface = playerInterface;}private PlayerInterface playerInterface;@Overridepublic void playFootBall() {playerInterface.playFootBall();}@Overridepublic void chooseFootBallTeam() {System.out.println("帮助球员选择伟大的俱乐部发展");}@Overridepublic void getAdvertisement() {System.out.println("帮助球员承接广告");}}

测试代码：

public class Test {public static void main(String[] args) {PlayerInterface footBallPlayer = new FootBallPlayer();PlayerInterface playerProxy = new PlayerProxy(footBallPlayer);playerProxy.playFootBall();playerProxy.chooseFootBallTeam();playerProxy.getAdvertisement();}}

输出内容如下：

驰骋足坛
帮助球员选择伟大的俱乐部发展
帮助球员承接广告

代码之动态代理：实现InvocationHandler接口

public class PlayerHandler implements InvocationHandler {private PlayerInterface playerInterface;public PlayerHandler(PlayerInterface playerInterface) {super();this.playerInterface = playerInterface;}@Overridepublic Object invoke(Object proxy, Method method, Object[] args)throws Throwable {//进行方法的筛选if(method.getName().equals("playFootBall")){method.invoke(playerInterface, args);}return null;}}

测试：

public static void main(String[] args) {PlayerInterface footBallPlayer = new FootBallPlayer();PlayerHandler handler = new PlayerHandler(footBallPlayer);PlayerInterface proxy = (PlayerInterface) Proxy.newProxyInstance(ClassLoader.getSystemClassLoader(), new Class[]{PlayerInterface.class}, handler);proxy.playFootBall();proxy.chooseFootBallTeam();proxy.getAdvertisement();}

控制台输出：因为只处理了playFootBall方法，故只打印了相关输出

驰骋足坛