几个http请求相关的函数

1、 通过HttpWebRequest发起一个Post请求，并获取返回数据

 1        /**//// <summary>
 2        /// 使用指定编码格式发送一个POST请求，并通过约定的编码格式获取返回的数据
 3        /// </summary>
 4        /// <param name="url">请求的url地址</param>
 5        /// <param name="parameters">请求的参数集合</param>
 6        /// <param name="reqencode">请求的编码格式</param>
 7        /// <param name="resencode">接收的编码格式</param>
 8        /// <returns></returns>
 9        public static string SendPostRequest(string url, NameValueCollection parameters, Encoding reqencode, Encoding resencode)
        {
            HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
            req.Method = "post";
            req.ContentType = "application/x-www-form-urlencoded";

            StringBuilder parassb = new StringBuilder();
            foreach (string key in parameters.Keys)
            {
                if (parassb.Length >0)
                    parassb.Append("&");
                parassb.AppendFormat("{0}={1}", key,parameters[key]);
            }
            byte[] data = reqencode.GetBytes(parassb.ToString());
            Stream reqstream = req.GetRequestStream();

            reqstream.Write(data, 0, data.Length);
            reqstream.Close();

            string result = String.Empty;
            using (StreamReader reader = new StreamReader(req.GetResponse().GetResponseStream(), resencode))
            {
                result = reader.ReadToEnd();
            }
            return result;
        }

2、通过HttpWebRequest发起一个Get请求，并获取返回数据

 1        /**//// <summary>
 2        /// 发送一个GET请求
 3        /// </summary>
 4        /// <param name="url">请求的url地址</param>
 5        /// <param name="parameters">请求的参数集合</param>
 6        /// <param name="reqencode">请求的编码格式</param>
 7        /// <param name="resencode">接收的编码格式</param>
 8        /// <returns></returns>
 9        public static string SendGetRequest(string baseurl, NameValueCollection parameters, Encoding reqencode, Encoding resencode)
        {
            StringBuilder parassb = new StringBuilder();
            foreach (string key in parameters.Keys)
            {
                if (parassb.Length > 0)
                    parassb.Append("&");
                parassb.AppendFormat("{0}={1}", HttpUtility.UrlEncode(key, reqencode), HttpUtility.UrlEncode(parameters[key], reqencode));
            }

            if (parassb.Length > 0)
            {
                baseurl += "?" + parassb;
            }
            HttpWebRequest req = (HttpWebRequest)WebRequest.Create(baseurl);
            req.Method = "GET";
            req.MaximumAutomaticRedirections = 3;
            req.Timeout = 5000;

            string result = String.Empty;
            using (StreamReader reader = new StreamReader(req.GetResponse().GetResponseStream(), resencode))
            {
                result = reader.ReadToEnd();
            }
            return result;

        }

3、通过编程的方式实现Post提交请求并重定向至新的URL地址

 1        /**//// <summary>
 2        /// Post请求并且重定向
 3        /// </summary>
 4        /// <param name="url"></param>
 5        /// <param name="parameters"></param>
 6        /// <param name="context"></param>
 7        public static void PostAndRedirect(string url,NameValueCollection parameters,HttpContext context)
 8        {
 9            StringBuilder script = new StringBuilder();
            script.AppendFormat("<form name=redirpostform action='{0}' method='post'>",url);
            foreach(string key in parameters.Keys)
            {
                script.AppendFormat("<input type='hidden' name='{0}' value='{1}'>",
                    key,parameters[key]);
            }
            script.Append("</form>");
            script.Append("<script language='javascript'>redirpostform.submit();</script>");
            context.Response.Write(script);
            context.Response.End();
        }