主要讲述了基于套接字（Socket）进行网络编程的基本概念，其中包括TCP协议、套接字、聊天程序的三种开发模式，以及两个基本操作：侦听端口、连接远程服务端；第二篇讲述了一个简单的范例：从客户端传输字符串到服务端，服务端接收并打印字符串，将字符串改为大写，然后再将字符串回发到客户端，客户端最后打印传回的字符串；-Mainly about the socket-based (Socket) to the basic concepts of network programming, including TCP, sockets, the three chat program development model, and two basic operations: listening port to connect to remote server　s two about a simple example: the string from the client to the server, the server receives and prints the string, the string to uppercase, and then the string back to the client, the client passed the final print back to the string