https://blog.csdn.net/sinat_26917383/article/details/52233341
https://blog.csdn.net/hadoopdevelop/article/details/86300109
https://www.cnblogs.com/zongfa/p/9557682.html
https://www.jianshu.com/p/fa97454c9ffd
https://zhuanlan.zhihu.com/p/31470216