http://blog.csdn.net/wzzvictory/article/details/18737437
http://blog.csdn.net/wzzvictory/article/details/19178709
http://blog.csdn.net/shaobo8910/article/details/46647995
解决冲突
http://blog.csdn.net/shaobo8910/article/details/46648433
http://www.jianshu.com/p/e4ee771af77b
