Question

Does anyone have any suggestions on how to convert data (mostly strings) into their formatted byte representation?

For example, if I enter the string “01” I’d like to get 00 01 or if I enter “0001” I’d like to get 00 00 00 01

I’ve tried using ByteBuffer but the output is always 8 bits long, i.e. 01 => 00 00 00 01

Answer 1

I have never seen this representation before as it sounds pretty inefficient. However what you can do is

public static void main(String... args) throws IOException {
    System.out.println("01 => " + Arrays.toString(byteValues("01")));
    System.out.println("0001 => " + Arrays.toString(byteValues("0001")));
    System.out.println("0123456789ABCDEF => " + Arrays.toString(byteValues("0123456789ABCDEF")));
}

public static byte[] byteValues(String text) {
    byte[] bytes = new byte[text.length()];
    for(int i=0;i<text.length();i++)
        bytes[i] = (byte) Character.getNumericValue(text.charAt(i));
    return bytes;
}

prints

01 => [0, 1]
0001 => [0, 0, 0, 1]
0123456789ABCDEF => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]