模拟登录（一次自动调转）

 class Class3
    {
        public static void A()
        {
            HttpWebRequest request = null;
            HttpWebResponse response = null;
            string gethost = string.Empty;
            CookieContainer cc = new CookieContainer();
            string Cookiesstr = string.Empty;
            try
            {

                //第一次POST请求
                string postdata = @"username=%E5%B0%8F%E5%B0%8F%E7%9A%84%E5%85%94%E5%85%94&loginFlag=1&userId=2356208%0D%0A";//模拟请求数据
                string LoginUrl = "http://szbbs.sznews.com/logging.php?action=login&curpage=%2Fsearch.php%3Fascdesc%3Ddesc%26before%3D%26formhash%3D81d3dcc0%26orderby%3Dlastpost%26searchsubmit%3Dtrue%26srchfid%255B%255D%3Dall%26srchfilter%3Dall%26srchfrom%3D0%26srchtxt%3Dtest%26srchtypeid%3D%26srchuname%3D";
                request = (HttpWebRequest)WebRequest.Create(LoginUrl);//实例化web访问类
                request.Method = "POST";//数据提交方式为POST
                //模拟头
                request.ContentType = "application/x-www-form-urlencoded";
                byte[] postdatabytes = Encoding.GetEncoding("gb2312").GetBytes(postdata);
                request.ContentLength = postdatabytes.Length;
                request.Referer = "login.sina.com.cn";
                request.AllowAutoRedirect = false;
                request.CookieContainer = cc;
                request.KeepAlive = true;
                //提交请求
                Stream stream;
                stream = request.GetRequestStream();
                stream.Write(postdatabytes, 0, postdatabytes.Length);
                stream.Close();
                //接收响应
                response = (HttpWebResponse)request.GetResponse();
                //保存返回cookie
                response.Cookies = request.CookieContainer.GetCookies(request.RequestUri);
                CookieCollection cook = response.Cookies;
                string strcrook = request.CookieContainer.GetCookieHeader(request.RequestUri);
                Cookiesstr = strcrook;
                //取第一次GET跳转地址
                StreamReader sr = new StreamReader(response.GetResponseStream(), Encoding.GetEncoding("UTF-8"));
                string content = sr.ReadToEnd();
                response.Close();
            }
            catch (Exception)
            {
                //第一次POST出错；
            }
            try
            {
                //Cookiesstr = @"cdb_sid=CdQgsf; cdb_cookietime=0; cdb_auth=FoJk27b3Ynm3s%2FvMEfuXmCtyweSWb9Go7lE7emrVJ80KJ%2FWpT1SfdcHvXPSiGsnM%2BVMstkFU6ng";
                gethost = "http://szbbs.sznews.com/search.php"; //第一次GET跳转地址
                request = (HttpWebRequest)WebRequest.Create(gethost);
                request.Method = "GET";
                request.KeepAlive = true;
                request.Headers.Add("Cookie:" + Cookiesstr);
                request.CookieContainer = cc;
                request.AllowAutoRedirect = false;
                response = (HttpWebResponse)request.GetResponse();
                //设置cookie   
                Cookiesstr = request.CookieContainer.GetCookieHeader(request.RequestUri);
                //取再次跳转链接   
                StreamReader sr = new StreamReader(response.GetResponseStream(), Encoding.UTF8);
                string content = sr.ReadToEnd();
                request.Abort();
                sr.Close();
                response.Close();
            }
            catch (Exception)
            {
                //第一次GET出错   
            }
           
        }
    }