可扩展消息出席协议（XMPP）的完全讲解，文档附带例子，通俗易懂。-Extensible Messaging and present Protocol (XMPP) fully explain, the document with examples, easy to understand.

基于xmpp协议的client端引擎的实现。包括基本的login、roster列表的获取、message的收发、presence的发送和接收处理，以及subscribe/subscribed的实现。-Xmpp agreement based on client-side engine to achieve. Including the basic login, roster list of access, message and delivery, presence of the sending