一些介绍：
https://www.jianshu.com/p/b7de8e4cf217
https://blog.csdn.net/javaloveiphone/article/details/52439613
https修改http: https://www.cnblogs.com/coder-lzh/p/9222467.html
流程图牛逼：https://blog.csdn.net/u010475041/article/details/77886765 还有系列博客
