http://www.cnblogs.com/TankXiao/archive/2012/12/12/2794160.html

https://blog.csdn.net/xiaoxiaorenky/article/details/6229734 good

https://blog.csdn.net/michealcxt/article/details/22939239

https://blog.csdn.net/zhyh1435589631/article/details/51623099 good

https://www.cnblogs.com/vipyoumay/archive/2017/08/31/7455431.html good

https://www.cnblogs.com/Anker/p/6056540.html good

HTTP代理服務器基本知識