DynamicProxyTest.java

package JavaPatternDemos;

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

/**
 * 动态代理，使用java提供的Proxy对象
 */
public class DynamicProxyTest {
 public static void main(String[] args) throws Exception{

 MyProxyImpl pObj = new MyProxyImpl();
 MyInvokeHandler myHandlder = new MyInvokeHandler(pObj);

 ProxyInterface proxyProduced = (ProxyInterface) Proxy.newProxyInstance(
 ProxyInterface.class.getClassLoader(),
 new Class<?>[]{ProxyInterface.class},
 myHandlder);

 System.out.println(proxyProduced.updateName("Badass"));
 }
}


interface ProxyInterface {
 String updateName(String name_);
}

class MyProxyImpl implements ProxyInterface {
 private String name = "default";

 public String updateName(String newName){
 System.out.println(name);
 name = newName;
 return newName;
 }
}

class MyInvokeHandler implements InvocationHandler{
 private Object target = null; //这里可以只针对ProxyInterface对象

 public MyInvokeHandler(Object aTarget){
 target = aTarget;
 }
 @Override
 public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
 // 这里的proxy实际上是生成的代理对象，见下面的Name，是$proxy0
 System.out.println("this is from a handler");
 System.out.println(proxy.getClass().getName());

 Object result = method.invoke(target,args);
 return result;
 }
}