MD5加密算法

    private String getMD5Str(String str) {

        MessageDigest messageDigest = null;

        try {

            messageDigest = MessageDigest.getInstance("MD5");

            messageDigest.reset();

            messageDigest.update(str.getBytes("UTF-8"));

        } catch (NoSuchAlgorithmException e) {

            System.out.println("NoSuchAlgorithmException caught!");

            System.exit(-1);

        } catch (UnsupportedEncodingException e) {

            e.printStackTrace();

        }

        byte[] byteArray = messageDigest.digest();

        StringBuffer md5StrBuff = new StringBuffer();

        for (int i = 0; i < byteArray.length; i++) {

            if (Integer.toHexString(0xFF & byteArray[i]).length() == 1)

                md5StrBuff.append("0").append(

                        Integer.toHexString(0xFF & byteArray[i]));

            else

                md5StrBuff.append(Integer.toHexString(0xFF & byteArray[i]));

        }

        return md5StrBuff.toString();

    }