static String toHex4ByteString(int i) {
		String hex = Integer.toHexString(i);
		if (hex.length() == 1)
			return "0000000" + hex;
		if (hex.length() == 2)
			return "000000" + hex;
		if (hex.length() == 3)
			return "00000" + hex;
		if (hex.length() == 4)
			return "0000" + hex;
		if (hex.length() == 5)
			return "000" + hex;
		if (hex.length() == 6)
			return "00" + hex;
		if (hex.length() == 7)
			return "0" + hex;
		return hex;
	}