MD5算法

/*
 * MD5 算法
 */
public class MD5
{
    
    // 全局数组
    private final static String[] strDigits = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f"};
    
    public MD5()
    {
    }
    
    // 返回形式为数字跟字符串
    private static String byteToArrayString(byte bByte)
    {
        int iRet = bByte;
        // System.out.println("iRet="+iRet);
        if (iRet < 0)
        {
            iRet += 256;
        }
        int iD1 = iRet / 16;
        int iD2 = iRet % 16;
        return strDigits[iD1] + strDigits[iD2];
    }
    
    // 返回形式只为数字
    @SuppressWarnings("unused")
    private static String byteToNum(byte bByte)
    {
        int iRet = bByte;
        if (iRet < 0)
        {
            iRet += 256;
        }
        return String.valueOf(iRet);
    }
    
    // 转换字节数组为16进制字串
    private static String byteToString(byte[] bByte)
    {
        StringBuffer sBuffer = new StringBuffer();
        for (int i = 0; i < bByte.length; i++)
        {
            sBuffer.append(byteToArrayString(bByte[i]));
        }
        return sBuffer.toString();
    }
    
    public static String GetMD5Code(String strObj)
    {
        String resultString = null;
        try
        {
            resultString = new String(strObj);
            MessageDigest md = MessageDigest.getInstance("MD5");
            // md.digest() 该函数返回值为存放哈希值结果的byte数组
            resultString = byteToString(md.digest(strObj.getBytes()));
        }
        catch (NoSuchAlgorithmException ex)
        {
            ex.printStackTrace();
        }
        return resultString;
    }
}