Converting a Hex String into 32 Bit Binary String

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() .