Url解码,兼容utf-8和gb2312

自己做个网站,发现百度的蜘蛛和Google的蜘蛛对Url的编码解码方式不一致,给我造成了很大的困惑啊,

做了一个函数,统一由此解码,世界清静了

顺便宣传一下网站地址 接龙大全

         protected void Page_Load(object sender, EventArgs e)
        {
            Response.Write(UrlDecode("xxx"));
        }

        /// <summary>
        /// Url通用解码
        /// 先尝试utf-8,再尝试gb2312
        /// </summary>
        /// <param name="key"></param>
        /// <returns></returns>
        public static string UrlDecode(string key)
        {
            string input = GetUrlParam(key).ToLower();
            if (input.Length == 0)
                return string.Empty;

            //首先用utf-8进行解码
            string result = HttpUtility.UrlDecode(input, Encoding.UTF8);

            // 将已经解码的字符再次进行编码.            
            string encode = HttpUtility.UrlEncode(result, Encoding.UTF8).ToLower();

            //与原来编码进行对比，如果不一致说明解码未正确，用gb2312进行解码
            if (input != encode)
                result = HttpUtility.UrlDecode(input, Encoding.GetEncoding("gb2312"));

            return result;
        }

        /// <summary>
        /// 获取Url的参数,不编码,只获取明码
        /// </summary>
        /// <param name="key"></param>
        /// <returns></returns>
        private static string GetUrlParam(string key)
        {
            if (System.Web.HttpContext.Current != null)
            {
                string query = HttpContext.Current.Request.Url.Query;
                if (query != null && query.Length > 0)
                {
                    int index = 0;
                    index = query.IndexOf(key + "=");
                    if (index >= 0)
                    {
                        query = query.Substring(key.Length + 1 + index);
                        index = query.IndexOf('&');
                        if (index >= 0)
                            query = query.Substring(0, index);
                        return query;
                    }
                }
            }
            return string.Empty;
        }