基于serverSocket 和socket编写的及时聊天系统。有类似于tencent的qq界面，能实时监听用户的上下线。能发离线消息。有用户连接池。以及账号注册，修改等功能-ServerSocket and socket-based chat system written in a timely manner. Tencent similar to those of the qq interface, real-time monitor on the user' s offline. Offline messages can be issued. A user connection pool. As well as account registration, modification and other functions