Converting an IP address to binary values (Java)

Question

I'm trying to write a program in Java that will take an IP address and convert to binary.

Here is what I have so far:

import java.util.Scanner;

public class IpConverter{

public static void main (String[]args)
{

    int result;

    String data_in;

    int data_out;

        Scanner scan = new Scanner(System.in);

        try
        {
            System.out.print("Enter an IP address: ");
            data_in = scan.next();

            data_out = Integer.parseInt(data_in, 10);
            System.out.println (data_in + "is equivalent to" + data_out);
        }
        catch (NumberFormatException nfe){
            System.out.println("Wrong data type!");

        }
    }
}

Solution 1

Building on jtahlborn' answer:

byte[] bytes = InetAddress.getByName(data_in).getAddress();
data_out = new BigInteger(1, bytes).toString(2);

Now data_out contains the IP address as a binary number.

Solution 2

you can use InetAddress to parse the textual representation and convert to a byte[]. you can use BigDecimal to convert a byte[] to a big integer.

Solution 3

Scanner in = new Scanner(System.in);
System.out.println("Please enter an IP Address.");
String ip = in.nextLine();
String[] octetArray = ip.split("\\.");
for (String string : octetArray){
    int octet = Integer.parseInt(string);
    String binaryOctet = Integer.toBinaryString(octet);
    System.out.println(binaryOctet);
}

so for input 10.10.150.1 output will be

1010

1010

10010110

1

Comments

[Marc B]

Assuming your ips are being entered in dotted.quad format (eg 127.0.0.1), parseint isn't going to give you a full 32bit representation of that, since that's not a valid int.

[Jeffrey]

For future reference, if you select all of your code and press CTRL+K you will get one big code block instead of the many small ones you originally had.

[jerms246]

Yes, 127.0.0.1 would be the format I want.

[Shuo Ran]

There are answers to the same question at stackoverflow.com/questions/1146581/…

[jerms246]

The string ip = in.nextLine(); command is giving me an error. "error: cannot find symbol String ip = in.nextLine();"

[Dan675]

That's weird, the code is copied directly from my code that ran fine.

[jerms246]

Anything else i need to import?Other than java.util.Scanner? I also have java.lang.String imported as well.

[Dan675]

Scanner is the only think you should need imported.

[jerms246]

Not working, man. You think you could add some more of your code to see if I'm missing anything?