字符串转16进制，16进制转Base64 哈哈哈 uf65/rn+

    private void Test()
        {
            string str = "哈哈哈";
            str = GetHexByString(str, Encoding.GetEncoding("GB18030"));//Encoding.GetEncoding("GBK")
            string eee = GetBase64By16Str(str);
        }

       
        /// <summary>
        /// 字符串转16进制通过
        /// </summary>
        /// <param name="str"></param>
        /// <param name="encode"></param>
        /// <returns></returns>
        public string GetHexByString(string str, Encoding encode)//StringToHexString
        {
            byte[] b = encode.GetBytes(str);
            StringBuilder result = new StringBuilder();
            for (int i = 0; i < b.Length; i++)
            {
                result.Append(Convert.ToString(b[i], 16));
            }
            return result.ToString();
        }


        /// <summary>
        /// 字符串转Base64
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static string GetBase64By16Str(string str)
        {
            try
            {

                System.Text.RegularExpressions.MatchCollection mc = Regex.Matches(str.ToString().ToUpper(), "[a-fA-F0-9]{2}");
                byte[] bytes = new byte[mc.Count];
                for (int i = 0; i < mc.Count; i++)
                {
                    bytes[i] = byte.Parse(mc[i].Value, System.Globalization.NumberStyles.HexNumber);
                }

                string res = Convert.ToBase64String(bytes);
                return res;
            }
            catch (FormatException)
            {
                //转换失败
                return null;
            }
        }