package com.dynamic;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.sql.Array;
import java.util.ArrayList;
import java.util.List;

public class TestHandler implements InvocationHandler {
  private Object proxiedObj;
  public TestHandler(Object obj){
    proxiedObj = obj;
  }
  
  public Object invoke(Object proxy, Method method, Object[] args)
      throws Throwable {
    System.out.println("1"); 
    Object obj = method.invoke(proxiedObj, args);
    System.out.println("2");
    return obj;
  }

  public static void main(String args[]){
    Hello hello = new Hello();
    Class helloClass = hello.getClass();
    IHello hello2 =(IHello)Proxy.newProxyInstance(helloClass.getClassLoader(),helloClass.getInterfaces(),new TestHandler(hello));
    hello2.sayHello();//在代理对象上调用方法时这些方法的调用会转变成对调用处理器的invoke方法的调用
  }
}
interface IHello{
  void sayHello();
}
class Hello implements IHello{
  public void sayHello(){
    System.out.println("hello world!");
  }
}

 


public static ​​Object​​ newProxyInstance(​​ClassLoader​​ loader, ​​Class​​<?>[] interfaces, ​​InvocationHandler​​ h) throws ​​IllegalArgumentException​​


     参数：

​​loader​​ - 定义代理类的类加载器

​​interfaces​​ - 代理类要实现的接口列表

​​h​​ - 指派方法调用的调用处理程序