代理模式-动态代理Demo(JDK自带的动态代理)

偏执的太偏执、 2022-06-06 01:36 229阅读 0赞

**1.说明：借用歌星与经济人（代理）在现实生活中的关系来阐述代理模式；**

**2.代码**

2.1明星接口

public interface Star{
    	void confer();
    	void signContract();
    	void bookTicket();
    	void sing();
    	void collectMoney();
    }

2.2真实明星实现明星接口

package 代理模式1.动态代理;
    
    public class RealStar implements Star {
    
    	@Override
    	public void confer() {
    		// TODO Auto-generated method stub
    		System.out.println("RealStar.confer()");
    		
    	}
    
    	@Override
    	public void signContract() {
    		// TODO Auto-generated method stub
    		System.out.println("RealStar.signContract()");
    	}
    
    	@Override
    	public void bookTicket() {
    		// TODO Auto-generated method stub
    		System.out.println("RealStar.bookTicket()");
    	}
    
    	@Override
    	public void sing() {
    		System.out.println("RealStar(周杰伦).sing()");
    		
    	}
    
    	@Override
    	public void collectMoney() {
    		// TODO Auto-generated method stub
    		System.out.println("RealStar.collectMoney()");
    		
    	}
    	
    }

2.3明星助手类实现java.lang.reflect.InvocationHandler接口，重写其public Object invoke(Object proxy, Method method, Object\[\] args)方法

package 代理模式1.动态代理;
    
    import java.lang.reflect.InvocationHandler;
    import java.lang.reflect.Method;
    
    public class StarHandler implements InvocationHandler{
    	Star realStar;
    	
    	public StarHandler(Star realStar){
    		super();
    		this.realStar = realStar;
    	}
    	
    	@Override
    	public Object invoke(Object proxy, Method method, Object[] args) 
    			throws Throwable {
    		Object object = null;
    		System.out.println("正真的方法执行前");
    		if("sing".equals(method.getName())){
    			object = method.invoke(realStar, args);
    		}
    		System.out.println("真正的方法执行后");
    		return object;
    	}
    
    }

2.4在Client类中进行调用

package 代理模式1.动态代理;
    
    import java.lang.reflect.Proxy;
    
    public class Client {
    	public static void main(String[] args) {
    		Star realStar = new RealStar();
    		StarHandler  handler = new StarHandler(realStar);
    		Star proxy = (Star) Proxy.newProxyInstance(ClassLoader.getSystemClassLoader(), new Class[]{Star.class}, handler);
    		//订票
    		proxy.bookTicket();
    		//唱歌
    		proxy.sing();
    	}
    }

**3.输出结果：**

**正真的方法执行前  
真正的方法执行后  
正真的方法执行前  
RealStar(周杰伦).sing()  
真正的方法执行后**