Question

How can I convert a Hex String into 32bit Binary String? I did

String binAddr = Integer.toBinaryString(Integer.parseInt(hexAddr, 16));

To get the Binary String, but I need to pad it with 0’s to ensure its 32 bits, how can I do that, preferably with Formatter?

Answer 1

String binAddr = Integer.toBinaryString(Integer.parseInt(hexAddr, 16)); 
String.format("%032", new BigInteger(binAddr));

The idea here is to parse the string back in as a decimal number temporarily (one that just so happens to consist of all 1’s and 0’s) and then use String.format().

Note that you basically have to use BigInteger, because binary strings quickly overflow Integer and Long resulting in NumberFormatExceptions if you try to use Integer.fromString() or Long.fromString().