private static final char HEX_DIGITS[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',    'A', 'B', 'C', 'D', 'E', 'F' };public static String toHexString(byte[] b) {  //String to byte  StringBuilder sb = new StringBuilder(b.length * 2);  for (int i = 0; i < b.length; i++) {    sb.append(HEX_DIGITS[(b[i] & 0xf0) >>> 4]);    sb.append(HEX_DIGITS[b[i] & 0x0f]);  }  return sb.toString();}public String md5(String s) {  try {    // Create MD5 Hash    MessageDigest digest = java.security.MessageDigest.getInstance("MD5");    digest.update(s.getBytes());    byte messageDigest[] = digest.digest();    return toHexString(messageDigest);  } catch (NoSuchAlgorithmException e) {    e.printStackTrace();  }  return "";}