How to convert a binary representation of a string into byte in Java?

Question

as the title says, how do I do it? Its easy to convert from string -> byte -> string binary, But how do I convert back? Below is a example. The output is : 'f' to binary: 01100110 294984

I read somewhere that I could use the Integer.parseInt but clearly that is not the case :( Or am I doing something wrong?

Thanks, :)

public class main{
    public static void main(String[] args) {

         String s = "f";
          byte[] bytes = s.getBytes();
          StringBuilder binary = new StringBuilder();
          for (byte b : bytes)
          {
             int val = b;
             for (int i = 0; i < 8; i++)
             {
                binary.append((val & 128) == 0 ? 0 : 1);
                val <<= 1;
             }
             binary.append(' ');
          }
          System.out.println("'" + s + "' to binary: " + binary);

        System.out.println(Integer.parseInt("01100110", 2));
    }
}

Solution 1

You can use Byte.parseByte() with a radix of 2:

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

---

Using your example:

System.out.println(Byte.parseByte("01100110", 2));

102

Solution 2

You can parse it to an integer in base 2, and convert to a byte array. In your example you've got 16 bits you can also use short.

short a = Short.parseShort(b, 2);
ByteBuffer bytes = ByteBuffer.allocate(2).putShort(a);

byte[] array = bytes.array();

Just in case if you need it for a Very Big String.

String b = "0110100001101001";
byte[] bval = new BigInteger(b, 2).toByteArray();