Java | Binary string to byte

Question

I want to convert a string that consists of 8 binary numbers to a byte. I have tried this method:

byte b = Byte.parseByte(s, 2);

Which works fine if the string is "00000000", but doesn't work if it is "11111111".

I suspect is has something to do with the Radix but I can not figure it out.

Nicolas Filotto · Accepted Answer · 2016-05-13 10:23:55Z

1

Use Integer.parseInt with a radix of 2 like this Integer.parseInt("11111111", 2)
Then if you really want it as a byte simply cast the integer to a byte like this (byte) intValue

So the complete code is:

System.out.println((byte) Integer.parseInt("11111111", 2));

Output:

-1

NB: Why -1? because byte is a signed integer of 8 bits going from -128 to 127 so here instead of having 255 you get -1.

answered May 13, 2016 at 10:14

Nicolas Filotto

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