import java.security.Key;
import java.security.SecureRandom;
import java.security.spec.AlgorithmParameterSpec;

import javax.crypto.Cipher;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.IvParameterSpec;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class Des
{
    public static final String ALGORITHM_DES = "DES/CBC/PKCS5Padding";
    private static Log log = LogFactory.getLog(Des.class);

    /**
     * DES算法，加密
     *
     * @param data 待加密字符串
     * @param key  加密私鑰，長度不能夠小于8位
     * @return 加密后的字節數組，一般結合Base64編碼使用
     * @throws CryptException 異常
     */
    public static String encode(String key,String data) throws Exception
    {
        return encode(key, data.getBytes());
    }
    /**
     * DES算法，加密
     *
     * @param data 待加密字符串
     * @param key  加密私鑰，長度不能夠小于8位
     * @return 加密后的字節數組，一般結合Base64編碼使用
     * @throws CryptException 異常
     */
    public static String encode(String key,byte[] data) throws Exception
    {
        try
        {
      DESKeySpec dks = new DESKeySpec(key.getBytes());

      SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
            //key的長度不能夠小于8位字節
            Key secretKey = keyFactory.generateSecret(dks);
            Cipher cipher = Cipher.getInstance(ALGORITHM_DES);
            IvParameterSpec iv = new IvParameterSpec("********".getBytes());
            AlgorithmParameterSpec paramSpec = iv;
            cipher.init(Cipher.ENCRYPT_MODE, secretKey,paramSpec);

            byte[] bytes = cipher.doFinal(data);
            return Base64.encode(bytes);
        } catch (Exception e)
        {
            throw new Exception(e);
        }
    }

    /**
     * DES算法，解密
     *
     * @param data 待解密字符串
     * @param key  解密私鑰，長度不能夠小于8位
     * @return 解密后的字節數組
     * @throws Exception 異常
     */
    public static byte[] decode(String key,byte[] data) throws Exception
    {
        try
        {
         SecureRandom sr = new SecureRandom();
      DESKeySpec dks = new DESKeySpec(key.getBytes());
      SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
            //key的長度不能夠小于8位字節
            Key secretKey = keyFactory.generateSecret(dks);
            Cipher cipher = Cipher.getInstance(ALGORITHM_DES);
            IvParameterSpec iv = new IvParameterSpec("********".getBytes());
            AlgorithmParameterSpec paramSpec = iv;
            cipher.init(Cipher.DECRYPT_MODE, secretKey,paramSpec);
            return cipher.doFinal(data);
        } catch (Exception e)
        {
//         e.printStackTrace();
            throw new Exception(e);
        }
    }

    /**
     * 獲取編碼后的值
     * @param key
     * @param data
     * @return
     * @throws Exception 
     * @throws Exception
     */
    public static String decodeValue(String key,String data) throws Exception 
    {
     byte[] datas;
     String value = null;

     datas = decode(key, Base64.decode(data));

  value = new String(datas);
  if (value.equals("")){
   throw new Exception();
  }
     return value;
    }
}