基于udp的聊天工具，在TCP/IP网络通信环境下，Socket数据传输是一种特殊的I/O，它也相当于一种文件描述符，具有一个类似于打开文件的函数调用-socket()。-UDP-based chat tools，Socket data transfer in TCP/IP network communication environment, a special I/O, it is equivalent to a file descr iptor, has a similar function