传json格式：
Parsed写：
User-Agent: Fiddler Host: localhost:1455 Content-Type: application/json; charset=utf-8 Content-Length: 38
request body写：
{"参数名":"参数值","参数名":"参数值"，...}
传的不是JSON格式的话
Parsed写：
User-Agent: Fiddler
Host: localhost:1455
Content-Type: application/x-www-form-urlencoded;charset=utf-8
Content-Length: 38
request body写：
name1=valule1&name2=value2...
Content-Type设置的很重要，设置滴和request body里面的数据类型不对。就不能传滴....
转自： http://blog.csdn.net/nongs/article/details/40150293
Fiddler的Request Builder(Composer)模拟发送POST请求
原文：http://www.cnblogs.com/someblue/p/4367437.html