http://www.360doc.com/content/10/0930/17/3668821_57590979.shtml
http://www.cnpaf.net/Class/HTTP/
http://wenku.baidu.com/view/795e6821af45b307e8719733.html
http://www.cnblogs.com/gpcuster/archive/2009/05/25/1488749.html
http://www.slideshare.net/zhangsj/http-4768773