http://www.oschina.net/code/snippet_89964_6009
http://blog.csdn.net/tender001/article/details/8469698
http://www.oschina.net/question/100569_11723
http://www.tuicool.com/articles/rMzAFj
http://blog.csdn.net/yaerfeng/article/details/7368541
原文：http://www.cnblogs.com/diyunpeng/p/5848228.html