DesUtils.java

package com.withiter.utils;

import java.security.InvalidKeyException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.security.Security;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;

/**
 * @author cross
 */
public class DesUtils {

	private static String strDefaultKey = "quhao";
	private Cipher encryptCipher = null;
	private Cipher decryptCipher = null;

	public static String byteArr2HexStr(byte[] arrB) {
		int iLen = arrB.length;
		StringBuffer sb = new StringBuffer(iLen * 2);
		for (int i = 0; i < iLen; i++) {
			int intTmp = arrB[i];
			while (intTmp < 0) {
				intTmp = intTmp + 256;
			}
			if (intTmp < 16) {
				sb.append("0");
			}
			sb.append(Integer.toString(intTmp, 16));
		}
		return sb.toString();
	}

	public static byte[] hexStr2ByteArr(String strIn) {
		byte[] arrB = strIn.getBytes();
		int iLen = arrB.length;

		byte[] arrOut = new byte[iLen / 2];
		for (int i = 0; i < iLen; i = i + 2) {
			String strTmp = new String(arrB, i, 2);
			arrOut[i / 2] = (byte) Integer.parseInt(strTmp, 16);
		}
		return arrOut;
	}

	public DesUtils() {
		this(strDefaultKey);
	}

	public DesUtils(String strKey) {
		Security.addProvider(new com.sun.crypto.provider.SunJCE());
		Key key = getKey(strKey.getBytes());

		try {
			encryptCipher = Cipher.getInstance("DES");
			encryptCipher.init(Cipher.ENCRYPT_MODE, key);

			decryptCipher = Cipher.getInstance("DES");
			decryptCipher.init(Cipher.DECRYPT_MODE, key);
		} catch (InvalidKeyException e) {
			e.printStackTrace();
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		} catch (NoSuchPaddingException e) {
			e.printStackTrace();
		}
	}

	public byte[] encrypt(byte[] arrB) throws IllegalBlockSizeException, BadPaddingException {
		return encryptCipher.doFinal(arrB);
	}

	public String encrypt(String strIn) {
		try {
			return byteArr2HexStr(encrypt(strIn.getBytes()));
		} catch (IllegalBlockSizeException e) {
			e.printStackTrace();
			return null;
		} catch (BadPaddingException e) {
			e.printStackTrace();
			return null;
		}
	}

	public byte[] decrypt(byte[] arrB) throws IllegalBlockSizeException, BadPaddingException {
		return decryptCipher.doFinal(arrB);
	}

	public String decrypt(String strIn) {
		try {
			return new String(decrypt(hexStr2ByteArr(strIn)));
		} catch (IllegalBlockSizeException e) {
			e.printStackTrace();
			return null;
		} catch (BadPaddingException e) {
			e.printStackTrace();
			return null;
		}
	}

	private Key getKey(byte[] arrBTmp) {
		byte[] arrB = new byte[8];

		for (int i = 0; i < arrBTmp.length && i < arrB.length; i++) {
			arrB[i] = arrBTmp[i];
		}
		Key key = new javax.crypto.spec.SecretKeySpec(arrB, "DES");
		return key;
	}
}