http://geek.csdn.net/news/detail/56031
http://www.jianshu.com/p/9988303b2429
http://blog.sina.com.cn/s/blog_acc991e50102w7zq.html
http://www.jianshu.com/p/3c59844df301/comments/935095
https://segmentfault.com/q/1010000005636505
原文：http://www.cnblogs.com/yeng/p/5915167.html