http://wiki.jabbercn.org/RFC3920
http://www.cnblogs.com/hoojo/archive/2012/06/18/2553975.html
http://www.cnblogs.com/luxiaofeng54/archive/2011/03/14/1984026.html
http://www.cnblogs.com/wihoho/archive/2012/03/27/2420157.html
原文：http://www.cnblogs.com/chuiyuan/p/4460717.html