参考地址：
http://blog.csdn.net/jy0902/article/details/50519115
http://blog.csdn.net/architect0719/article/details/53066451
http://blog.csdn.net/u013485533/article/details/42774645
http://blog.csdn.net/u011179993/article/details/50817834
http://zk-chs.iteye.com/blog/2293013
这个博客http://blog.csdn.net/Architect0719/article/category/6200890总结的不错。