http协议（一）

      HTTP is also used as a generic protocol for communication between user agents and proxies/gateways to other Internet systems, including
those supported by the SMTP [16], NNTP [13], FTP [18], Gopher [2],and WAIS [10] protocols. In this way, HTTP allows basic hypermedia access to resources available from diverse applications.【NNTP:Network News Transfer Protocal,网络新闻传输协议】,【http://www.cnblogs.com/helloczh/admin/wais:Wide Area Information Servers,广域网信息服务】