指定字符串加密（对称加密DES）

/*
 * @(#) EncrypAES.java
 */
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

/**
 * 功能描述: 这里注意二进制转十六进制，十六进制转二进制的必要性                            
 
 * @version 2.4.0 
 * @Copyright (c) 2002-2013 All rights reserved.  
 * @create 2012-12-13 上午11:11:02
 **/
public class EncrypDes {
    private static final String key="travelSkyGuiParameter";
    
    private SecretKeyFactory keyFactory = null;
    // 生成加密密钥
    private DESKeySpec keySpec = null;
    
    private SecretKey secretKey = null;
    
    private Cipher cipher = null;
    
    public EncrypDes() throws InvalidKeyException, NoSuchAlgorithmException, InvalidKeySpecException, NoSuchPaddingException{
        //KeySpec组成加密密钥的密钥内容的（透明）规范
        keySpec = new DESKeySpec(key.getBytes());
        keyFactory = SecretKeyFactory.getInstance("DES");
        // key的长度不能够小于8位字节
        secretKey = keyFactory.generateSecret(keySpec);
        cipher = Cipher.getInstance("DES");
    }
    
    public String Encrytor(String str) throws InvalidKeyException, NoSuchAlgorithmException,
        InvalidKeySpecException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException {             
        // 根据密钥，对Cipher对象进行初始化，ENCRYPT_MODE表示加密模式
        cipher.init(Cipher.ENCRYPT_MODE, secretKey);
        byte[] src = str.getBytes();
        // 加密，结果保存进cipherByte
        byte[] encryByte = cipher.doFinal(src);
        String encryStr = parseByte2HexStr(encryByte);
        return encryStr;        
    }
    
    public String Decryptor(String str) throws InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
        // 根据密钥，对Cipher对象进行初始化，DECRYPT_MODE表示加密模式
        byte[] encryByte = parseHexStr2Byte(str);
        cipher.init(Cipher.DECRYPT_MODE, secretKey);
        return new String(cipher.doFinal(encryByte));
        /*byte[] decryByte = cipher.doFinal(encryByte);
        return parseByte2HexStr(decryByte);*/
    }  
    
    /**将二进制转换成16进制
     * @param buf
     * @return
     */
    public static String parseByte2HexStr(byte buf[]) {
            StringBuffer sb = new StringBuffer();
            for (int i = 0; i < buf.length; i++) {
                    String hex = Integer.toHexString(buf[i] & 0xFF);
                    if (hex.length() == 1) {
                            hex = '0' + hex;
                    }
                    sb.append(hex.toUpperCase());
            }
            return sb.toString();
    }
    
    /**将16进制转换为二进制
     * @param hexStr
     * @return
     */
    public static byte[] parseHexStr2Byte(String hexStr) {
            if (hexStr.length() < 1)
                    return null;
            byte[] result = new byte[hexStr.length()/2];
            for (int i = 0;i< hexStr.length()/2; i++) {
                    int high = Integer.parseInt(hexStr.substring(i*2, i*2+1), 16);
                    int low = Integer.parseInt(hexStr.substring(i*2+1, i*2+2), 16);
                    result[i] = (byte) (high * 16 + low);
            }
            return result;
    }      
    
    public static void main(String[] args) throws Exception {
        EncrypDes des = new EncrypDes();
        EncrypDes des2 = new EncrypDes();
        String msg = "test_1212_我爱你——@#￥%……&";       
        String encontent = des.Encrytor(msg);                
        String encontent2 = des2.Encrytor(msg);      
        String decontent = des.Decryptor(encontent);
        String decontent2 = des2.Decryptor(encontent);     
        System.out.println("明文是:" + msg);   
        System.out.println("加密后:" + encontent);        
        System.out.println("解密后:" +decontent);
        System.out.println("加密后:" + encontent2);
        System.out.println("解密后:" + decontent2);
        System.out.println("is equals:" + encontent.equals(encontent2));
    }  
}