java动态代理Dynamic Proxy

1.被代理对象的接口:

package test.dynamicproxy;



public interface TargetInterface {

	public void SayHello();

	public int sum(int a ,int b);

}

 

2.被代理的对象:

package test.dynamicproxy;



public class Target implements TargetInterface {



	public void SayHello(){

		System.out.println("Hello");

	}

	public int sum(int a, int b) {

		return a+b;

	}

}

 

3.InvocationHandler包装:

package test.dynamicproxy;



import java.lang.reflect.InvocationHandler;

import java.lang.reflect.Method;



public class TargetInvocationHandler implements InvocationHandler {



	private Object object;

	public TargetInvocationHandler(Object obj){

		this.object=obj;

	}

	

	public Object invoke(Object proxy, Method method, Object[] args2)

	throws Throwable

	{

		doBefore();

		Object result = method.invoke(object, args2);

		doAfter();

		return result;

	}



	public void doBefore(){

		System.out.println("do before");

	}



	public void doAfter(){

		System.out.println("do after");

	}

}

4.测试类:

package test.dynamicproxy;



import java.lang.reflect.Proxy;



public class TestDynamicProxy {



	/**

	 * @param args

	 */

	public static void main(String[] args) {

		Target t=new Target();

		TargetInvocationHandler handler=new TargetInvocationHandler(t);

		

		TargetInterface proxy = (TargetInterface) Proxy.newProxyInstance(

				t.getClass().getClassLoader(),

				t.getClass().getInterfaces(),

				handler);

				

		proxy.SayHello();



		int b=proxy.sum(10, 20);

		System.out.println(b);

	}



}