http://www.cnblogs.com/dyllove98/archive/2013/08/06/3241140.html
http://blog.csdn.net/afgasdg/article/details/9236877
http://www.cnblogs.com/bronte/articles/1885481.html
http://blog.csdn.net/sunyujia/article/details/2614614
原文：http://www.cnblogs.com/diyunpeng/p/4358874.html