10.代理模式(Proxy)

1.代理模式就是给一个对象提供一个代理对象，由这个代理对象控制对原对象的引用，便代理类在客户端和原对象之间起到一个中介的作用.

 

2.代理对象主要由3部分组成:抽象目标类、具全的目标类和代理类.

 

3.代理模式可分为静态代理与动态代理

 

静态代理例子:

 

package com.proxy;

public interface Test {
	
	public void doLogic(String name);

}


package com.proxy;

public class TestImpl implements Test{

	public void doLogic(String name) {
		System.out.println(name + "开始处理业务逻辑!");
		
	}

}



package com.proxy;

public class TestProxy implements Test{
	
	private Test test;

	public TestProxy(Test test){
		this.test = test;
	}
	
	public void doLogic(String name) {
		System.out.println("开始日志............");
		test.doLogic(name);
		System.out.println("结束日志............");
		
	}

}



package com.proxy;

public class Client {
	
	public static void main(String[] args) {
		TestProxy proxy = new TestProxy(new TestImpl());
		proxy.doLogic("小明");
	}
}

 

 

动态代理例子:

 

package com.proxy2;

public interface Test {
	
	public void doLogic(String name);

}


package com.proxy2;

public class TestImpl implements Test{

	public void doLogic(String name) {
		System.out.println(name + "处理业务中..........");
		
	}

}


package com.proxy2;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

public class LogProxy implements InvocationHandler{
	
	private Object delegate;
	
	//绑定代理对象
	public Object bind(Object delegate){
		this.delegate = delegate;
		return Proxy.newProxyInstance(delegate.getClass().getClassLoader(), delegate.getClass().getInterfaces(), this);
	}
	
	

	public Object invoke(Object proxy, Method method, Object[] args)
			throws Throwable {
		
		Object result = null;
		try {
			System.out.println("【日志】业务处理开始.......");
			result =  method.invoke(delegate, args);
			System.out.println("【日志】业务处理结束.........");
		} catch (Exception e) {
			e.printStackTrace();
		}
		
		return result;
	}

}


package com.proxy2;

public class Client {
	
	public static void main(String[] args) {
		Test test = new TestImpl();
		
		LogProxy proxy = new LogProxy();
		Test s = (Test)proxy.bind(test);
		s.doLogic("小白");
		
	}

}

 

 

说明:一般被代理的目标类要写接口,

(return Proxy.newProxyInstance(delegate.getClass().getClassLoader(), delegate.getClass().getInterfaces(), this);
)

 

当然你也可以用开源框架CGlib来实现.

 

 

4.UML