参考文档：
http://blog.csdn.net/u011649536/article/details/45043781
http://blog.csdn.net/zm2714/article/details/7977930
http://www.blogjava.net/qileilove/archive/2013/08/23/403216.html
http://www.jianshu.com/p/9823ac1fcb69
http://blog.csdn.net/artwebs/article/details/20716431
原文：http://www.cnblogs.com/zoeya/p/7121177.html