private static final String KEY ="xxxJE234D";//64个字符串

    public static String encryptString(String plaintext) throws Exception{

        Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");

        DESKeySpec desKeySpec = new DESKeySpec(KEY.getBytes("UTF-8"));

        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");

        SecretKey secretKey = keyFactory.generateSecret(desKeySpec);

        IvParameterSpec iv = new IvParameterSpec(KEY.substring(0, 8).getBytes("UTF-8"));

        cipher.init(Cipher.ENCRYPT_MODE, secretKey, iv);

        byte[] bt = cipher.doFinal(plaintext.getBytes("UTF-8"));

        String strs = new BASE64Encoder().encode(bt).replaceAll("[+]", "%2B");

        return strs;

    }

    public static string ToEncrypt2(string str, string myKey)

        {

            string encryptKeyall = Convert.ToString(myKey);    //定义密钥

            if (encryptKeyall.Length < )

            {

                for (; ; )

                {

                    if (encryptKeyall.Length < )

                        encryptKeyall += encryptKeyall;

                    else

                        break;

                }

            }

            string encryptKey = encryptKeyall.Substring(, );

            DESCryptoServiceProvider descsp = new DESCryptoServiceProvider();   //实例化加/解密类对象

            descsp.Mode = CipherMode.CBC;

            descsp.Padding = PaddingMode.PKCS7;

            byte[] key = Encoding.UTF8.GetBytes(encryptKey); //定义字节数组，用来存储密钥

            byte[] data = Encoding.UTF8.GetBytes(str);//定义字节数组，用来存储要加密的字符串

            MemoryStream MStream = new MemoryStream(); //实例化内存流对象

            //使用内存流实例化加密流对象

            CryptoStream CStream = new CryptoStream(MStream, descsp.CreateEncryptor(key, key), CryptoStreamMode.Write);

            CStream.Write(data, , data.Length);  //向加密流中写入数据

            CStream.FlushFinalBlock();              //释放加密流

            return Convert.ToBase64String(MStream.ToArray()).Replace("+", "%2B");//返回加密后的字符串

        }

  public static string Encrypt(string pToEncrypt, string sKey)

        {

            using (DESCryptoServiceProvider des = new DESCryptoServiceProvider())

            {

                byte[] inputByteArray = Encoding.UTF8.GetBytes(pToEncrypt);

                des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);

                des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);

                System.IO.MemoryStream ms = new System.IO.MemoryStream();

                using (CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write))

                {

                    cs.Write(inputByteArray, , inputByteArray.Length);

                    cs.FlushFinalBlock();

                    cs.Close();

                }

                string str = Convert.ToBase64String(ms.ToArray());

                ms.Close();

                return str;

            }

        }

//解密

    /// <summary>

        /// 进行DES解密

        /// </summary>

        /// <param name="pToDecrypt">要解密的以Base64</param>

        /// <param name="sKey">密钥，且必须为8位</param>

        /// <returns>已解密的字符串</returns>

        public static string Decrypt(string pToDecrypt, string sKey)

        {

            byte[] inputByteArray = Convert.FromBase64String(pToDecrypt);

            using (DESCryptoServiceProvider des = new DESCryptoServiceProvider())

            {

                des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);

                des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);

                System.IO.MemoryStream ms = new System.IO.MemoryStream();

                using (CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write))

                {

                    cs.Write(inputByteArray, , inputByteArray.Length);

                    cs.FlushFinalBlock();

                    cs.Close();

                }

                string str = Encoding.UTF8.GetString(ms.ToArray());

                ms.Close();

                return str;

            }

        }