说明：  多线程Java Socket编程示例,其中采用Java 5的ExecutorService来进行线程池的方式实现多线程,模拟客户端多用户向同一服务器端发送请求.
(Multi-threaded Java Socket programming examples, including the use of Java 5 to the thread pool ExecutorService way to achieve multi-threaded, multi-user simulation client to the same server-side send the request.)