我用的C#模拟表单post提交。下面是我用burp拦下的本机发出的请求包。可以看到，第一个参数名前面出现了莫名其妙的字符……搜索了好久也没找到原因。希望能得到各位前辈的指点。

网页要求的编码是utf-8,我这边用的编码也是utf-8。 burp包如图：

下面是我的代码。

//postdata
string data = string.Format("j_password={0}&j_username={1}&j_captcha_response={2}", psw, name,          yzm);
//请求
  string ans = Model.Variable.dd.HttpPost("http://ecar.95590.cn/ecar/j_spring_security_check", data,        "http://ecar.95590.cn/ecar/view/ecar/login/login.jsp");



//dd.HttpPost
 public string HttpPost(string Url, string postDataStr, string referer)
    {
        HttpWebRequest request = (HttpWebRequest) WebRequest.Create(Url);
        request.Method = "POST";
        request.ContentType = "application/x-www-form-urlencoded";
        request.CookieContainer = this.cookie;
        request.Referer = referer;
        StreamWriter writer = new StreamWriter(request.GetRequestStream(), Encoding.GetEncoding("utf-8"));
        writer.Write(postDataStr);
        writer.Close();
        HttpWebResponse response = null;
        try
        {
            this.SetCertificatePolicy();
            response = (HttpWebResponse) request.GetResponse();
        }
        catch (Exception)
        {
        }
        if (response != null)
        {
            Stream responseStream = response.GetResponseStream();
            StreamReader reader = new StreamReader(responseStream, Encoding.GetEncoding("utf-8"));
            string str = reader.ReadToEnd();
            reader.Close();
            responseStream.Close();
            return str.Replace(" ", "").Replace("rn", "").Replace("t", "");
        }
        return "error";
    }