http://blog.csdn.net/u011012932/article/details/50557057
http://blog.csdn.net/u011012932/article/details/50557240
http://blog.csdn.net/u011012932/article/details/50553111
http://blog.csdn.net/u011012932/article/details/50555298
原文：http://www.cnblogs.com/findumars/p/5962435.html