http://blog.csdn.net/conan8126/article/details/8178784
https://zhidao.baidu.com/question/1895081853813115540.html
https://www.cnblogs.com/dyfzwj/archive/2011/04/16/2017916.html
http://blog.csdn.net/liehuo123/article/details/6924644
http://blog.csdn.net/tony0225/article/details/38014431
http://www.jb51.net/article/80620.htm
