http://blog.youkuaiyun.com/chenssy/article/details/12952063
http://blog.youkuaiyun.com/zhangjg_blog/article/details/18369201
http://www.cnblogs.com/carbs/archive/2012/06/26/2564373.html
http://www.cnblogs.com/o-andy-o/archive/2012/04/06/2434904.html