/// <summary> 按照api说明对signature进行校验，校验成功返回参数echostr </summary>
        /// <returns></returns>
        public string CheckSign()
        {
            var httpMethod = Request.HttpMethod.ToLower();
            string httpString = string.Empty;
            if (httpMethod == "get")
            {
                httpString = Request.QueryString.ToString();
            }
            else if (httpMethod == "post")
            {
                httpMethod = Request.Form.ToString();
            }
            else
            {
                httpMethod = "请求方式不是get和post";
            }
            var strSignature = Request["signature"];
            var strEchostr = Request["echostr"];
            var strToken = "58jiancai";
            var strTimestamp = Request["timestamp"];
            var strNonce = Request["nonce"];

            log4net.LogManager.GetLogger("请求方式").Info(httpMethod);
            log4net.LogManager.GetLogger("请求字符串").Info(httpString);
            log4net.LogManager.GetLogger("pram1.strSignature").Info(strSignature);
            log4net.LogManager.GetLogger("pram2.strEchostr").Info(strEchostr);
            log4net.LogManager.GetLogger("pram3.strToken").Info(strToken);
            log4net.LogManager.GetLogger("pram4.strTimestamp").Info(strTimestamp);
            log4net.LogManager.GetLogger("pram5.strNonce").Info(strNonce);

            //step1:字典序排序
            string[] array = new[] { strToken, strTimestamp, strNonce };
            Array.Sort(array);
            log4net.LogManager.GetLogger("sort").Info(array[0] + "||" + array[1] + "||" + array[2]);

            //step2:sha1加密
            var strResult = FormsAuthentication.HashPasswordForStoringInConfigFile(string.Concat(array), "SHA1").ToLower();
            log4net.LogManager.GetLogger("sha1").Info(strResult);

            //step3:加密后的字符串与参数signature值比较
            if (strResult == strSignature.ToLower())
            {
                log4net.LogManager.GetLogger("result").Info("success");
                return strEchostr;
            }
            log4net.LogManager.GetLogger("result").Info("fail");
            return string.Empty;
        }