实例讲解Java设计模式编程中如何运用代理模式

package Proxy;
//抽象主题类：
public interface Subject {
  public void doSomething();
}

package Proxy;
//具体主题类
public class RealSubject implements Subject{
  @Override
  public void doSomething() {
    System.out.println("业务逻辑...");
  }
}

package Proxy;
//代理主题类
public class Proxy implements Subject{
   
  private Subject sub = null; 
   
  @Override
  public void doSomething() {
    this.sub.doSomething();   
  }
   
  public Proxy(Subject sub){
    this.sub = sub;
  }
   
   
}

package Proxy;
//客户端
public class Client {
  public static void main(String[] args) {
     
    Subject realsub = new RealSubject();
    Subject proxy = new Proxy(realsub);
     
    proxy.doSomething();
  }
}

package GeneralProxy;
 
public interface Subject {
  public void doSomething();
}

package GeneralProxy;
 
public class RealSubject implements Subject{
   
  private String name = null;
   
  @Override
  public void doSomething() {
    System.out.println(this.name + "被代理，正在执行业务逻辑...");
  }
   
  public RealSubject(Subject proxy,String name) throws Exception{
    if(proxy == null){
      throw new Exception("无法创建被代理对象");
    }else{
      this.name = name;
    }
       
  }
}

package GeneralProxy;
 
public class Proxy implements Subject{
 
  private Subject realsub = null;
     
  public Proxy(String name) {
    try {
      realsub = new RealSubject(this, name);
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
   
  public void doSomething() {
    realsub.doSomething();
  }
}

package GeneralProxy;
 
public class Client {
  public static void main(String[] args) {
    //普通代理
    Subject proxy = new Proxy("张三");        
    proxy.doSomethaing();
  }
   
}

package MustProxy;
 
public interface Subject {
  public void doSomething();
   
  public Subject getProxy();
}

package MustProxy;
 
public class RealSubject implements Subject{
   
  private String name = null;
  private Subject proxy = null;
   
  @Override
  public void doSomething() {
    if(isProxy()){
      System.out.println(this.name + "被代理，正在执行业务逻辑...");
    }else{
      System.out.println("请先访问代理...");
    }
     
  }
   
  public RealSubject(String name) {
    this.name = name;
  }
   
  public Subject getProxy() {
 
    proxy = new Proxy(this);
    return this.proxy;
  }
   
  private boolean isProxy(){
    if(this.proxy == null){
      return false;
    }else{
      return true;
    }
       
  }
}

package MustProxy;
 
public class Proxy implements Subject{
 
  private Subject realSub = null;
   
  public Proxy(Subject realSub) {
    this.realSub = realSub;
  }
   
  public void doSomething() {   
    this.realSub.doSomething();
  }
   
 
  public Subject getProxy() {
 
    return this;
  }
}

package MustProxy;
 
public class Client {
  public static void main(String[] args) {
    Subject realSub = new RealSubject("张三");
    realSub.doSomething();
     
    Subject proxy = realSub.getProxy();
    proxy.doSomething();
  }
}