Convert hex string to binary string

Question

I would like to convert a hex string to a binary string. For example, Hex 2 is 0010. Below is the code:

String HexToBinary(String Hex)
{
    int i = Integer.parseInt(Hex);
    String Bin = Integer.toBinaryString(i);
    return Bin;
}

However this only works for Hex 0 - 9; it won't work for Hex A - F because it uses int. Can anyone enhance it?

Answer 1

You need to tell Java that the int is in hex, like this:

String hexToBinary(String hex) {
    int i = Integer.parseInt(hex, 16);
    String bin = Integer.toBinaryString(i);
    return bin;
}

Answer 2

the accepted version will only work for 32 bit numbers.

Here's a version that works for arbitrarily long hex strings:

public static String hexToBinary(String hex) {
    return new BigInteger(hex, 16).toString(2);
}