http://littcai.iteye.com/blog/1900018
http://www.oschina.net/question/575914_90957
http://www.dengchuanhua.com/132.html
twitter/snowflake
https://github.com/twitter/snowflake
https://twitter.github.io/twitter-server/
原文：http://www.cnblogs.com/majia1949/p/4316445.html