java设计模式―静态代理模式(聚合与继承方式对比)

2019-11-26 12:16:47

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来源：转载

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一、概述

1.目标：要在Tank的move()方法做时间代理及日志代理(可以设想以后还要增加很多代理处理)，且代理间的顺序可活更换

2.思路：

(1)聚合：代理类聚合了被代理类，且代理类及被代理类都实现了movable接口，则可实现灵活多变，具体看代码

(2)继承：继承不够灵活，随着功能需求增多，继承体系会非常臃肿。具体看代码

二、代码

1.Movable.java

2.Tank.java

3.TankTimeProxy.java

4.TankLogProxy.java

5.Tank2Time.java

6.Tank3Log.java

7.Client.java

1.Movable.java

 public interface Movable {  public void move(); }

2.Tank.java

import java.util.Random;public class Tank implements Movable { @Override public void move() {  System.out.println("Tank moving.......");  try {   Thread.sleep(new Random().nextInt(5000));  } catch (InterruptedException e) {   e.printStackTrace();  } }}

3.TankTimeProxy.java

public class TankTimeProxy implements Movable { Movable m;  public TankTimeProxy(Movable m) {  this.m = m; } @Override public void move() {  System.out.println("Time Proxy start...........");  long start = System.currentTimeMillis();  m.move();  long end = System.currentTimeMillis();  System.out.println("花费时间："+(end - start));  System.out.println("Time Proxy end..........."); }}

4.TankLogProxy.java

public class TankLogProxy implements Movable { Movable m;  public TankLogProxy(Movable m) {  this.m = m; } @Override public void move() {  System.out.println("Log Proxy start...........");  m.move();  System.out.println("Log Proxy end..........."); }}

5.Tank2Time.java

public class Tank2Time extends Tank { public void move(){  System.out.println("Tank2 time start...........");  long start = System.currentTimeMillis();  super.move();  long end = System.currentTimeMillis();  System.out.println("花费时间："+(end - start));  System.out.println("Tank2 time end..........."); }}

6.Tank3Log.java

public class Tank3Log extends Tank2Time { public void move(){  System.out.println("Tank3Log start...........");  super.move();  System.out.println("Tank3Log end..........."); }}

7.Client.java

public class Client { @Test public void testProxy(){    Tank t = new Tank();  Movable m;    //一、聚合的方式(较灵活，因为实现了接口)  //1.1聚合方式的代理,先日志代理，后时间代理  TankTimeProxy ttp1 = new TankTimeProxy(t);  TankLogProxy tlp1 = new TankLogProxy(ttp1);    m = tlp1;  m.move();    System.out.println("/n==============================分隔线==========================/n");    //1.2聚合方式的代理,先时间代理，后日志代理(可以灵活切换顺序)  TankLogProxy tlp2 = new TankLogProxy(t);  TankTimeProxy ttp2 = new TankTimeProxy(tlp2);    m = ttp2;  m.move();    System.out.println("/n==============================分隔线==========================/n");    //二、继承的方式  //2.1代理时间  Tank2Time t2 = new Tank2Time();  t2.move();    System.out.println("/n==============================分隔线==========================/n");    //2.2先代理日志，后时间，不能灵活切换  Tank3Log t3 = new Tank3Log();  t3.move();  }}

三、运行结果