Question

In my Java Program, I need a byte array from a Hex String. So I do the following:

byte[] key=HexUtils.convert("0AA387ED291F6D90");

This converts the Hex String into a byte array as follows:

Output: Byte Array: key:[10, -93, -121, -19, 41, 31, 109, -112]

Now, I want to move the Hex String into the properties file. But I am not able to do so.

Try 1:
Properties file ====> key=0AA387ED291F6D90
Java Program ====> byte[] key = HexUtils.convert(prop.getProperty("key"));

This gives error: BAD HEXADECIMAL DIGIT

Try 2:
Properties file ====> key=\u000A\u00A3\u0087\u00ED\u0029\u001F\u006D\u0090
Java Program ====> byte[] key = HexUtils.convert(prop.getProperty("key"));

Output: key:[10, -93, 63, -19, 41, 31, 109, 63]

If you notice, 2 bytes are different than the Expected. Hex 87 and Hex 90. Both are converted to 63. Whereas I am expecting -121 and -112 respectively.

Can somebody please help me as to how do I do this conversion. I hope I am clear!

Angad

Answer 1

If using the \uxxxx codes, you’re using UNICODE escape sequences. \u0090 is not going to end up being interpreted as String "90", it’s gonna end up as a single character that corresponds to code unit 0090 in the UTF-16 encoding.

Your first approach should work. I suggest you try System.out.println(prop.getProperty("key")); or some other form of output and check if there’s leading or trailing white space, some character you didn’t expect or null. The latter would mean the property for “key” isn’t found.