java如何使用DES进行加密和解密呢？

package com.java265.javaUtil;

import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.spec.InvalidKeySpecException;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
 
public class DESUtil {

	/** 安全密钥 */
	private String keyData = "ABCDEFGHIJKLMNOPQRSTWXYZabcdefghijklmnopqrstwxyz0123456789-_.";

 	public DESUtil() {
	}

	public DESUtil(String key) {
		this.keyData = key;
	}

	public String encrypt(String source) throws UnsupportedEncodingException {
		return encrypt(source, "UTF-8");
	}

	/**
	 * 功能：解密 (UTF-8)
	 */
	public String decrypt(String encryptedData)
			throws UnsupportedEncodingException {
		return decrypt(encryptedData, "UTF-8");
	}

	/**
	 * 功能：加密
	 */
	public String encrypt(String source, String charSet)
			throws UnsupportedEncodingException {
		String encrypt = null;
		byte[] ret = encrypt(source.getBytes(charSet));
		encrypt = new String(Base64.encode(ret));
		return encrypt;
	}

	/**
	 * 功能：解密
	 */
	public String decrypt(String encryptedData, String charSet)
			throws UnsupportedEncodingException {
		String descryptedData = null;
		byte[] ret = descrypt(Base64.decode(encryptedData.toCharArray()));
		descryptedData = new String(ret, charSet);
		return descryptedData;
	}

	private byte[] encrypt(byte[] primaryData) {

		/** 取得安全密钥 */
		byte rawKeyData[] = getKey();

		/** DES算法要求有一个可信任的随机数源 */
		SecureRandom sr = new SecureRandom();

		/** 使用原始密钥数据创建DESKeySpec对象 */
		DESKeySpec dks = null;
		try {
			dks = new DESKeySpec(keyData.getBytes());
		} catch (InvalidKeyException e) {
			e.printStackTrace();
		}

		/** 创建一个密钥工厂 */
		SecretKeyFactory keyFactory = null;
		try {
			keyFactory = SecretKeyFactory.getInstance("DES");
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		}

		/** 用密钥工厂把DESKeySpec转换成一个SecretKey对象 */
		SecretKey key = null;
		try {
			key = keyFactory.generateSecret(dks);
		} catch (InvalidKeySpecException e) {
			e.printStackTrace();
		}

		/** Cipher对象实际完成加密操作 */
		Cipher cipher = null;
		try {
			cipher = Cipher.getInstance("DES");
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		} catch (NoSuchPaddingException e) {
			e.printStackTrace();
		}

		/** 用密钥初始化Cipher对象 */
		try {
			cipher.init(Cipher.ENCRYPT_MODE, key, sr);
		} catch (InvalidKeyException e) {
			e.printStackTrace();
		}

		/** 正式执行加密操作 */
		byte encryptedData[] = null;
		try {
			encryptedData = cipher.doFinal(primaryData);
		} catch (IllegalStateException e) {
			e.printStackTrace();
		} catch (IllegalBlockSizeException e) {
			e.printStackTrace();
		} catch (BadPaddingException e) {
			e.printStackTrace();
		}

		/** 返回加密数据 */
		return encryptedData;
	}

	/**
	 * 用密钥解密数据
	 */
	private byte[] descrypt(byte[] encryptedData) {

		/** DES算法要求有一个可信任的随机数源 */
		SecureRandom sr = new SecureRandom();

		/** 取得安全密钥 */
		byte rawKeyData[] = getKey();

		/** 使用原始密钥数据创建DESKeySpec对象 */
		DESKeySpec dks = null;
		try {
			dks = new DESKeySpec(keyData.getBytes());
		} catch (InvalidKeyException e) {
			e.printStackTrace();
		}

		/** 创建一个密钥工厂 */
		SecretKeyFactory keyFactory = null;
		try {
			keyFactory = SecretKeyFactory.getInstance("DES");
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		}

		/** 用密钥工厂把DESKeySpec转换成一个SecretKey对象 */
		SecretKey key = null;
		try {
			key = keyFactory.generateSecret(dks);
		} catch (InvalidKeySpecException e) {
			e.printStackTrace();
		}

		/** Cipher对象实际完成加密操作 */
		Cipher cipher = null;
		try {
			cipher = Cipher.getInstance("DES");
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		} catch (NoSuchPaddingException e) {
			e.printStackTrace();
		}

		/** 用密钥初始化Cipher对象 */
		try {
			cipher.init(Cipher.DECRYPT_MODE, key, sr);
		} catch (InvalidKeyException e) {
			e.printStackTrace();
		}

		/** 正式执行解密操作 */
		byte decryptedData[] = null;
		try {
			decryptedData = cipher.doFinal(encryptedData);
		} catch (IllegalStateException e) {
			e.printStackTrace();
		} catch (IllegalBlockSizeException e) {
			e.printStackTrace();
		} catch (BadPaddingException e) {
			e.printStackTrace();
		}

		return decryptedData;
	}

	/**
	 * 取得安全密钥 此方法作废,因为每次key生成都不一样导致解密加密用的密钥都不一样， 从而导致Given final block not
	 */
	private byte[] getKey() {

		/** DES算法要求有一个可信任的随机数源 */
		SecureRandom sr = new SecureRandom();

		/** 为我们选择的DES算法生成一个密钥生成器对象 */
		KeyGenerator kg = null;
		try {
			kg = KeyGenerator.getInstance("DES");
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		}
		kg.init(sr);

		/** 生成密钥工具类 */
		SecretKey key = kg.generateKey();

		/** 生成密钥byte数组 */
		byte rawKeyData[] = key.getEncoded();

		return rawKeyData;
	}
}