http://www.cnblogs.com/lwbqqyumidi/p/3837629.html
http://blog.csdn.net/sunxianghuang/article/details/51982979
http://www.cnblogs.com/iyangyuan/archive/2013/04/09/3011274.html
http://blog.csdn.net/bitcarmanlee/article/details/52336135
原文：http://www.cnblogs.com/hadoop-dev/p/7056021.html