/***************************************************/
注意：请求消息也是可以发送实体头域的，见下例（这是一个上传文件的请求）
// 命令行
POST /test/upload.asp HTTP/1.1
// 请求头域
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-silverlight, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, application/x-shockwave-flash, */*
Referer: http://localhost/test/upload.html
Accept-Language: zh-cn
// 实体头域，同时在这里面定义了表单内各个参数的分界符
Content-Type: multipart/form-data; boundary=---------------------------7d91a15915e6
//
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; Embedded Web Browser from: http://bsalsa.com/; .NET CLR 1.1.4322; .NET CLR 2.0.50727)
Host: localhost
// 实体头域
Content-Length: 0
Connection: Keep-Alive
Cache-Control: no-cache
Cookie: ASPSESSIONIDCCSDBCQQ=DEDDBOJBFHPMGCHEJPLGGLHH
Authorization: Negotiate TlRMTVNTUAABAAAAB7IIogYABgAqAAAAAgACACgAAAAFASgKAAAAD0hQTVNIT01F
// 这后面整个部分都是实体信息：
// 表单参数一：
-----------------------------7d919f7915e6
Content-Disposition: form-data; name="file1"; filename="C:\Documents and Settings\Administrator\桌面\系统设计的几点想法.txt"
Content-Type: text/plain
1、分析系统的角色，比如系统管理员，用户
2、分析每类角色的功能需求
3、从需求中提炼名词，建立词汇表
4、建立用户模型
5、系统抽象
// 表单参数二：
-----------------------------7d919f7915e6
Content-Disposition: form-data; name="upload"
上传
// 表单参数三：
-----------------------------7d919f7915e6
Content-Disposition: form-data; name="post"
hello
// 表单结束标记
-----------------------------7d919f7915e6--
/*******************************************************/
表单中如果要上传文件，则表单的enctype必须为"multipart/form-data"，可能是因为要支持上传
各种MIME类型的文件，而一般表单提交的时候，其请求头为：
POST /test/www.sinocoaa.com HTTP/1.1
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-silverlight, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, application/x-shockwave-flash, */*
Referer: http://localhost/test/TestFormReqHeader.html
Accept-Language: zh-cn
Content-Type: application/x-www-form-urlencoded
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; Embedded Web Browser from: http://bsalsa.com/; EmbeddedWB 14.52 from: http://www.bsalsa.com/ EmbeddedWB 14.52; .NET CLR 1.1.4322; .NET CLR 2.0.50727)
Host: localhost
Content-Length: 151
Connection: Keep-Alive
Cache-Control: no-cache
// 实体信息
dlExamPlan=1&CheckBox2=on&tbUnitCode=fasdf&tbAreaCode=
asdfasdfasd&tbSchoolCode=fasdfa&btnCreateReport=%E7%
BB%9F%E8%AE%A1%E6%88%90%E7%BB%A9&CheckBox1=on
即使没有上传文件输入框，如上例，如果设置了enctype为"multipart/form-data",则请求头就变为如下形式：
POST /test/www.sinocoaa.com HTTP/1.1
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-silverlight, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, application/x-shockwave-flash, */*
Referer: http://localhost/test/TestFormReqHeader.html
Accept-Language: zh-cn
Content-Type: multipart/form-data; boundary=---------------------------7d9251252e0fbc
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; Embedded Web Browser from: http://bsalsa.com/; EmbeddedWB 14.52 from: http://www.bsalsa.com/ EmbeddedWB 14.52; .NET CLR 1.1.4322; .NET CLR 2.0.50727)
Host: localhost
Content-Length: 791
Connection: Keep-Alive
Cache-Control: no-cache
-----------------------------7d9251252e0fbc
Content-Disposition: form-data; name="dlExamPlan"
1
-----------------------------7d9251252e0fbc
Content-Disposition: form-data; name="CheckBox2"
on
-----------------------------7d9251252e0fbc
Content-Disposition: form-data; name="tbUnitCode"
fasdf
-----------------------------7d9251252e0fbc
Content-Disposition: form-data; name="tbAreaCode"
dfasdfasd
-----------------------------7d9251252e0fbc
Content-Disposition: form-data; name="tbSchoolCode"
fasdfasd
-----------------------------7d9251252e0fbc
Content-Disposition: form-data; name="btnCreateReport"
统计成绩
-----------------------------7d9251252e0fbc
Content-Disposition: form-data; name="CheckBox1"
on
-----------------------------7d9251252e0fbc--
/***********************************************************/