package com.kangdy.test;

public interface UserManager {
 public void addUser(String  userName);
}

package com.kangdy.test;

public class UserManagerImpl implements UserManager {

 public void addUser(String userName) {
  System.out.println("用戶 : "+userName+" 添加成功");
 }

}

package com.kangdy.test;

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

public class JDKStaticProxy implements InvocationHandler{
 //目標對象索引
 private Object targetObject;
 
 /*
  * 通過構造方法引入目標對象
  */
 public JDKStaticProxy(Object targetObject){
  this.targetObject = targetObject;
 }
 
 /*
  * 創建代理對象
  */
 public Object createProxyObject(){
  Object proxyObject = Proxy.newProxyInstance(
    this.targetObject.getClass().getClassLoader(),
    this.targetObject.getClass().getInterfaces(), this);
  return proxyObject;
 }
 
 /*
  * proxyObject:代理對象
  * method: 被攔截到的目標對象的method
  * args: 被攔截到的目標對象的method的參數
  * (non-Javadoc)
  * @see java.lang.reflect.InvocationHandler#invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
  */
 public Object invoke(Object proxyObject, Method method, Object[] args)
   throws Throwable {
  //添加業務邏輯
  busniessLogic();
  
  //代理運行目標對象的method
  Object result = method.invoke(this.targetObject, args);
  return result;
 }
 
 /*
  * 添加業務邏輯，這里只是簡單打印一句話。
  */
 private void busniessLogic(){
  System.out.println("這是代理方法");
 }
 
}

package com.kangdy.test;

import org.junit.Test;

public class TestJDKStaticProxy {
 
 @Test public void testJDKStaticProxy(){
  JDKStaticProxy proxy = new JDKStaticProxy(new UserManagerImpl());
     UserManager userManager = (UserManager) proxy.createProxyObject();
  userManager.addUser("張三");
  
 }
}