使用Proxy的newProxyInstance方法创建动态代理。

  1. public static Object newProxyInstance(ClassLoader loader,
  2.                                       Class<?>[] interfaces,
  3.                                       InvocationHandler h)
  4.  loader：自然是类加载器
  5.  interfaces：需要代理的接口
  6.  h：InvocationHandler对象
  1. public interface InvocationHandler{
  2.     public Object invoke(Object proxy, Method method, Object[] args) throws Throwable;
  3. }
  4. proxy :代理对象
  5. method：代理对象调用的方法
  6. args：调用的方法中的参数

例子

  1. package com.cimon.simplerpc.prework;
  3. import java.lang.reflect.InvocationHandler;
  4. import java.lang.reflect.Method;
  5. import java.lang.reflect.Proxy;
  7. /**
  8.  * @author  chenrenbing
  9.  * @date  2021/06/20
  10.  *  动态代理模式
  11.  * */
  12. public class DynamicProxyDemo {
  13.     public static void main(String args[]){
  14.         WineService wineService1 = new WineServiceImpl1();
  15.         WineService wineService2 = new WineServiceImpl2();
  16.         InvocationHandler handler1 = new WineHandler(wineService1);
  17.         InvocationHandler handler2 = new WineHandler(wineService2);
  19.         WineService proxy1 = (WineService) Proxy.newProxyInstance(WineService.class.getClassLoader(),wineService1.getClass().getInterfaces(),handler1);
  20.         proxy1.sellWine();
  21.         proxy1.amount(1499);
  22.         WineService proxy2 = (WineService) Proxy.newProxyInstance(WineService.class.getClassLoader(),wineService1.getClass().getInterfaces(),handler2);
  23.         proxy2.sellWine();
  24.         proxy2.amount(999);
  25.     }
  26. }
  28. interface WineService{
  29.     void sellWine();
  30.     int amount(int a);
  31. }
  32. class WineServiceImpl1 implements WineService{
  33.     public void sellWine(){
  34.         System.out.println(" 茅台... ");
  35.     }
  36.     public int amount(int a){
  37.         System.out.println(" 茅台价格 : "+ a+"元");
  38.         return a;
  39.     }
  40. }
  41. class WineServiceImpl2 implements WineService{
  42.     public void sellWine(){
  43.         System.out.println(" 五粮液... ");
  44.     }
  45.     public int amount(int a){
  46.         System.out.println(" 五粮液 : "+ a+"元");
  47.         return a;
  48.     }
  49. }
  51. class WineHandler implements InvocationHandler{
  52.     private Object wine;
  53.     public WineHandler(Object wine){
  54.         this.wine = wine;
  55.     }
  56.     public Object invoke(Object proxy, Method method, Object[] args) throws Throwable{
  57.         System.out.println(" 卖酒了..." + this.wine.getClass().getSimpleName());
  58.         Object result = method.invoke(wine,args);
  59.         System.out.println(" 卖完了....");
  60.         return result;
  61.     }
  62. }
  64. 运行结果：
  65.  卖酒了...WineServiceImpl1
  66.  茅台... 
  67.  卖完了....
  68.  卖酒了...WineServiceImpl1
  69.  茅台价格 : 1499元
  71.  卖完了....
  72.  卖酒了...WineServiceImpl2
  73.  五粮液... 
  74.  卖完了....
  75.  卖酒了...WineServiceImpl2
  76.  五粮液 : 999元
  77.  卖完了....

参考
1、java中的代理模式