法_算_密_加_5_D_M

/**
* MD5加密
*/
public class Crypt
{
    @SuppressWarnings("nls")
    private final static String[] hexDigits = {"0", "1", "2", "3", "4", "5",
            "6", "7", "8", "9", "a", "b", "c", "d", "e", "f"};
   
    /**
     * 把inputString加密    
     * @param inputString
     * @return  String
     */
    public String generatePassword(String inputString)
    {
        return encodeByMD5(inputString);
    }
   
    /**
     * TODO 添加方法注释
     * @param password
     * @param inputString
     * @return boolean
     */
    public boolean validatePassword(String password, String inputString)
    {
        if (password.equals(encodeByMD5(inputString)))
        {
            return true;
        }
        else
        {
            return false;
        }
    }
   
    /**
     * TODO 添加方法注释
     * @param originString
     * @return String
     */
    public static String returnEncodeByMde(String originString)
    {
        return encodeByMD5(originString);
    }
   
    /**  对字符串进行MD5加密     */
    private static String encodeByMD5(String originString)
    {
        if (originString != null)
        {
            try
            {
                MessageDigest md = MessageDigest.getInstance("MD5"); //$NON-NLS-1$
                //使用指定的字节数组对摘要进行最后更新，然后完成摘要计算    
                byte[] results = md.digest(originString.getBytes());
                //将得到的字节数组变成字符串返回    
                String resultString = byteArrayToHexString(results);
                String pass = resultString.toUpperCase();
                return pass;
            }
            catch (Exception ex)
            {
                ex.printStackTrace();
            }
        }
        return null;
    }
   
    private static String byteArrayToHexString(byte[] b)
    {
        StringBuffer resultSb = new StringBuffer();
        for (int i = 0; i < b.length; i++)
        {
            resultSb.append(byteToHexString(b[i]));
        }
        return resultSb.toString();
    }
   
    /** 将一个字节转化成十六进制形式的字符串     */
    private static String byteToHexString(byte b)
    {
        int n = b;
        if (n < 0)
            n = 256 + n;
        int d1 = n / 16;
        int d2 = n % 16;
        return hexDigits[d1] + hexDigits[d2];
    }
   
    /**
     * 测试
     * @param args
     */
    @SuppressWarnings("nls")
    public static void main(String[] args)
    {
        String pwd1 = "123";
        String pwd2 = "";
        Crypt cipher = new Crypt();
        System.out.println("未加密的密码:" + pwd1);
        //将123加密    
        pwd2 = cipher.generatePassword(pwd1);
        System.out.println("加密后的密码:" + pwd2);
       
        System.out.print("验证密码是否下确:");
        if (cipher.validatePassword(pwd2, pwd1))
        {
            System.out.println("正确");
        }
        else
        {
            System.out.println("错误");
        }
    }