/** 是否财付通签名,规则是:按参数名称a-z排序,遇到空值的参数不参加签名。
         * @return boolean */
        public virtual Boolean _isTenpaySign(ArrayList akeys)
        {
            StringBuilder sb = new StringBuilder();

            foreach (string k in akeys)
            {
                string v = (string)parameters[k];
                if (null != v && "".CompareTo(v) != 0 &&
                    "sign".CompareTo(k) != 0 && "key".CompareTo(k) != 0)
                {
                    sb.Append(k + "=" + v + "&");
                }
            }

            sb.Append("key=" + this.getKey());
            string sign = MD5Util.GetMD5(sb.ToString(), getCharset()).ToLower();

            //debug信息
            this.setDebugInfo(sb.ToString() + " => sign:" + sign);
            return(getParameter("sign").ToLower().Equals(sign));
        }