Asp.net中 UTF-8 to GB2312 And GB2312 to UTF-8 第二种方法

public string UTF8ToGB2312()
        {
            try
            {
                Encoding utf8 = Encoding.GetEncoding(65001);
                Encoding gb2312 = Encoding.GetEncoding("gb2312");
                byte[] temp = utf8.GetBytes(Request.QueryString["u"]);
                byte[] temp1 = Encoding.Convert(utf8, gb2312, temp);
                string result = gb2312.GetString(temp1);
                return result;
            }
            catch (Exception ex)
            {
                return null;
            }
        }

        public string GB2312ToUTF8(string str)
        {
            try
            {
                Encoding uft8 = Encoding.GetEncoding(65001);
                Encoding gb2312 = Encoding.GetEncoding("gb2312");
                byte[] temp = gb2312.GetBytes(str);
                byte[] temp1 = Encoding.Convert(gb2312, uft8, temp);
                string result = uft8.GetString(temp1);
                return result;
            }
            catch (Exception ex)
            {
                return null;
            }
        }