生成MD5加密

 　　　　 /// <summary>
        /// MD5加密
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static string CalcMD5(this string str)
        {
            byte[] bytes = System.Text.Encoding.UTF8.GetBytes(str);
            return CalcMD5(bytes);
        }
        public static string CalcMD5(byte[] bytes)
        {
            using (MD5 md5 = MD5.Create())
            {
                byte[] computeBytes = md5.ComputeHash(bytes);
                string result = "";
                for (int i = 0; i < computeBytes.Length; i++)
                {
                    result += computeBytes[i].ToString("X").Length == 1 ? "0" + computeBytes[i].ToString("X") : computeBytes[i].ToString("X");
                }
                return result;

            }

        }
        public static string CalcMD5(Stream stream)
        {
            using (MD5 md5 = MD5.Create())
            {
                byte[] computeBytes = md5.ComputeHash(stream);
                string result = "";
                for (int i = 0; i < computeBytes.Length; i++)
                {
                    result += computeBytes[i].ToString("X").Length == 1 ? "0" +
                    computeBytes[i].ToString("X") : computeBytes[i].ToString("X");
                }
                return result;
            }
        }