httpPost 请求

public static string HttpPost(string url, byte[] postData)
        {
            HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
            request.Method = "post";
            request.ContentType = "application/x-www-form-urlencoded";
            request.ContentLength = postData.Length;
            request.CookieContainer = new CookieContainer();//页面跳转是携带cookie信息
            Stream requestStream = request.GetRequestStream();
            requestStream.Write(postData, 0, postData.Length);
            requestStream.Close();
            HttpWebResponse respone = (HttpWebResponse)request.GetResponse();
            StreamReader read = new StreamReader(respone.GetResponseStream(), Encoding.GetEncoding("utf-8"));
            string result = read.ReadToEnd();
            return result;
        }