CODEWITHSUNDEEP
javabinaryip-addressconverters
jerms246
jerms246

Reputation: 61

Converting an IP address to binary values (Java)

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!");

        }
    }
}

Upvotes: 3

Views: 16836

Answers (5)

Sean F
Sean F

Reputation: 4605

The open-source IPAddress Java library can do this for you. It can parse various IP address formats, including either IPv4 or IPv6. Disclaimer: I am the project manager of the IPAddress library.

Here is sample code similar to yours:

public static void main(String[] args) {
    try(Scanner scan = new Scanner(System.in)) {
        System.out.print("Enter IP addresses: ");
        while(true) {
            String data_in = scan.next();
            IPAddressString string = new IPAddressString(data_in);
            IPAddress addr = string.toAddress();
            System.out.println(addr + " is equivalent to " + addr.toBinaryString());
        }
    } catch (AddressStringException e){
        System.out.println("invalid format: " + e.getMessage());
    } catch(NoSuchElementException e) {}
}

Example usage: 

Enter IP addresses: 1.2.3.4 a:b:c:d:e:f:a:b
1.2.3.4 is equivalent to 00000001000000100000001100000100
a:b:c:d:e:f:a:b is equivalent to 00000000000010100000000000001011000000000000110000000000000011010000000000001110000000000000111100000000000010100000000000001011

Upvotes: 0

Michael Yakobi
Michael Yakobi

Reputation: 1140

If you want to avoid name resolution, you can use the following code that converts an IPv4 address string to a byte array: 

String[] octetArray = ipAddressStr.split("\\.");
assert octetArray.length == 4;
byte[] ipAddressBytes = new byte[4];
for (int i = 0; i < 4; ++i) {
    ipAddressBytes[i] = Integer.valueOf(octetArray[i]).byteValue();
}

Upvotes: 0

&#211;scar L&#243;pez
&#211;scar L&#243;pez

Reputation: 236004

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.

Upvotes: 7

Dan675
Dan675

Reputation: 1767

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

Upvotes: 2

jtahlborn
jtahlborn

Reputation: 53694

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.

Upvotes: 4

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