多线程实现：

需求：1、实现服务器与客户端的通信，服务器可接收多个客户端。

2、服务器发送消息时，所有客户端都可收到。

3、客户端发送信息时，只有服务器可收到。

4、服务器发送“bye”时，包括服务器程序及所有客户端程序都结束，客户端发送“bye”时，本客户端结束（当然，服务器对应的线程也会结束）。

5、服务器要在输出客户端消息时，要连同对应客户端的IP一起输出。

-Multithreading: Requirements: 1, server and client communications, the server can receive multiple clients. 2, the server sends a message, all clients can receive. 3, the client sends information, only the server can be received. 4, the server sends " bye"　when including the server program and the end of all client programs, the client sends " bye" , the client end (of course, the server corresponding thread also ends). 5, the server to the client in the output message to the client' s IP with the corresponding output together.