String to byte conversion

Question

How can I convert a string to byte? For example, Byte.parseByte("255"); causes NumberFormatException since (for some weird reason) byte is signed in java so the maximum value it can have is 127.

So I need a function such that

public static byte toByte(String input) {
...
}

And for example toByte("255"); should return -1(ie bits: 11111111)

Something like implementation of 2s complement

Answer 1

Use Integer.parseInt("255") and cast the resulting int to a byte:

byte value = (byte)Integer.parseInt("255");

Answer 2

byte value = (byte)Integer.parseInt("255");

Answer 3

   public static void main(String[] args) {    
     String s = "65";
     byte b = Byte.valueOf(s);
     System.out.println(b);

     // Causes a NumberFormatException since the value is out of range
     System.out.println(Byte.valueOf("129"));
  }

Answer 4

I am thinking of the following implementation!

public static byte toByte(String input) {
    Integer value = new Integer(input);

    // Can be removed if no range checking needed.
    // Modify if different range need to be checked.
    if (value > 255 || value < 0)
        throw new NumberFormatException("Invalid number");

    return value.byteValue();
}