java 代理模式，观察者模式

代理模式1

import <a href="http://lib.csdn.net/base/17" class='replace_word' title="Java EE知识库" target='_blank' style='color:#df3434; font-weight:bold;'>Java</a>.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

public class ProxyTest {

    public static void main(String[] args) {
        SaleComputer saleComputer = new ComputerMaker();
        InvocationHandler handler = new SaleProxy(saleComputer);

        SaleComputer proxy = (SaleComputer)Proxy.newProxyInstance(saleComputer.getClass().getClassLoader(), saleComputer.getClass().getInterfaces(), handler);
        proxy.saleComputer("花花");
    }

}

interface SaleComputer{ //卖电脑
    public void saleComputer(String type);
}

class ComputerMaker implements SaleComputer{

    public void saleComputer(String type) {
        System.out.println("卖出一台 " + type +" 牌电脑！");
    }

}

class SaleProxy implements InvocationHandler{

    Object delegate;

    public SaleProxy(Object delegate) {
        this.delegate = delegate;
    }

    public Object invoke(Object proxy, Method method, Object[] args)
            throws Throwable {
        giveMouse();
        return method.invoke(delegate,args);
    }

    private void giveMouse(){
        System.out.println("送鼠标...............");
    }

}

代理模式2

public class ProxyTest1 {

    public static void main(String[] args) {

        SaleComputer1 saleComputer = new ComputerMaker1();
        SaleComputer1 proxy = new SaleProxy1(saleComputer);
        proxy.saleComputer("鸿润");
    }

}

interface SaleComputer1{ //接口
    public void saleComputer(String type);
}

class ComputerMaker1 implements SaleComputer1{//实现类

    public void saleComputer(String type) {
        System.out.println("卖出一台 " + type +" 牌电脑！");
    }
}

class SaleProxy1 implements SaleComputer1{   //代理类

    SaleComputer1 delegate;

    public SaleProxy1(Object delegate){
        this.delegate = (SaleComputer1)delegate;
    }

    public void saleComputer(String type) {
        this.giveMouse();
        delegate.saleComputer(type);
    }

    private void giveMouse(){
        System.out.println("送鼠标...............");
    }
}

 观察者模式：

package com.model;

import java.util.Observable;
import java.util.Observer;

/**
    Java的API为我们提供了Observer接口和Observable类来实现所谓观察者模式。
    Observable(可观察者）类允许在自身发生改变时，通知其它对象（实现接口Observer，观察者）。
 */
public class TestObserver{

    public static void main(String[] args){

        Produce produce = new Produce();
        NameObserver nameObserver = new NameObserver();
        PriceObserver priceObserver = new PriceObserver();

        produce.addObserver(nameObserver);
        produce.addObserver(priceObserver);

        produce.setName("Apple");
        produce.setPrice(100);

    }
}

//一个可观察者
class Produce extends Observable{

    private String name;
    private Integer price;

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
        setChanged();          //设置变化点
        notifyObservers(name); //通知观察者
    }
    public Integer getPrice() {
        return price;
    }
    public void setPrice(Integer price) {
        this.price = price;
        setChanged();
        notifyObservers(price);
    }

}

//两个观察者
class NameObserver implements Observer{

    public void update(Observable o, Object arg) {
        if(arg instanceof String){
            System.out.println("观察者观察到：产品名字已经改为： " +  arg);
        }
    }

}

class PriceObserver implements Observer{

    public void update(Observable o, Object arg) {
        if(arg instanceof Integer){
            System.out.println("观察者观察到：价格已经改为： " +  arg);
        }
    }

}