http://blog.csdn.net/t12x3456/article/details/8982198
http://blog.csdn.net/ljx19900116/article/details/49903899
http://blog.csdn.net/ljx19900116/article/details/49903861
http://my.oschina.net/u/1777508/blog/345846?fromerr=AFQ6AcQK
原文：http://www.cnblogs.com/diyunpeng/p/5240256.html