http://www.oschina.net/question/100267_61129?sort=default&p=1#tags_nav

http://www.cnblogs.com/top5/archive/2011/12/29/2306241.html

http://www.open-open.com/lib/view/open1342353575260.html

 http://blog.csdn.net/ithomer/article/details/7896313