在java项目中实现MD5加密的方法有哪些

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();}