抓了个包,请问cookie里面的数据怎么模仿

POST /Login.do HTTP/1.1
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*
Referer: http://xiaonei.com/SysHome.do
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)
Host: xiaonei.com
Content-Length: 86
Connection: Keep-Alive
Cache-Control: no-cache
Cookie: XNESSESSIONID=abcCA3VOmC_Nb81XPqeBr; __utmc=204579609; userid=232475098; univid=11451; gender=0; univyear=2007; hostid=232475098; FSESSIONINS=3150321162.20480.0000; mop_uniq_ckid=61.184.112.14_1197293649_201180545; __utma=204579609.1170091208.1197293653.1197293653.1197293653.1; __utmb=204579609; __utmz=204579609.1197293653.1.1.utmccn=(direct)|utmcsr=(direct)|utmcmd=(none)[email protected]&password=111111&origURL=%2FSysHome.do&submit=%E7%99%BB%E5%BD%95抓了个包,不知道cookie里面是提交的还是服务端发过来的.
因为userid=232475098;肯定是服务端得到的.然而提交的cookie里面却有.这个是第一个send 包,不知道通过什么手法可以模仿.请高手明示
我想实现模拟登陆功能.