https://download.csdn.net/download/boyxiejunboy/8911091
http://www.mamicode.com/info-detail-121337.html
https://blog.csdn.net/zp___waj/article/details/51182961
https://www.cnblogs.com/kuangbin/archive/2012/10/16/2725596.html
http://blog.sina.com.cn/s/blog_68629c7701010c6h.html
https://blog.csdn.net/weiguang_123/article/details/7954626