GET 从指定的url上获取内容
POST 提交body中的内容给服务器中指定的url中，属于非幂等的(non-idempotent)请求
HEAD 从指定的url上获取header内容(类似Get方式)
TRACE Allows a programmer to see how the client's message is modified as it passes through a series of proxy servers. The recipient of a TRACE method echoes the HTTP request headers back to the client
PUT 将body上传至服务器指定url处
DELETE 在指定url处删除资源
OPTIONS 获取指定url中能接收的请求方法
CONNECT 连接指定频段。当客户端需要通过代理服务器连接HTTPS服务器是用到。
1.GET
例子：
GET /select/selectBeerTaste.jsp?color=dark&taste=malty HTTP/1.1 Host: www.wickedlysmart.com User-Agent: Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.4) Gecko/ 20030624 Netscape/7.1 Accept: text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/ plain;q=0.8,video/x-mng,image/png,image/jpeg,image/gif;q=0.2,*/*;q=0.1 Accept-Language: en-us,en;q=0.5 Accept-Encoding: gzip,deflate Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7 Keep-Alive: 300 Connection: keep-alive
2.POST
例子：
POST /advisor/selectBeerTaste.do HTTP/1.1 Host: www.wickedlysmart.com User-Agent: Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.4) Gecko/ 20030624 Netscape/7.1 Accept: text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/ plain;q=0.8,video/x-mng,image/png,image/jpeg,image/gif;q=0.2,*/*;q=0.1 Accept-Language: en-us,en;q=0.5 Accept-Encoding: gzip,deflate Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7 Keep-Alive: 300 Connection: keep-alive
color=dark&taste=malty
GET vs POST ：除了大小不同，前者能保存书签，后者不是幂等性的，表单默认是GET方式提交除非指定method=post