Convert IPv4 To Number

This post shows the code required to convert an IPv4 Address to a Number and vice versa.

The below-mentioned lines convert an IPv4 Address to Long.

// IP
String ip = "192.168.1.1";

// IP Octets string array
String[] octets = ip.split( "\\." );

// IP Octets integer array
int[] octetsNum = new int[] {
	Integer.parseInt( octets[ 0 ] ), 
	Integer.parseInt( octets[ 1 ] ),
	Integer.parseInt( octets[ 2 ] ), 
	Integer.parseInt( octets[ 3 ] )
};

// IP in numeric form
long ipNum = ( octetsNum[ 0 ] * (int)Math.pow( 256, 3 ) ) + ( octetsNum[ 1 ] * (int)Math.pow( 256, 2 ) ) + ( octetsNum[ 2 ] * 256 ) + ( octetsNum[ 3 ] );

We can also convert the number back to IPv4 Address as shown below.

// IP in numeric form
long ipNum = -1062731519;

// Convert numeric IP to IPv4 Address
String ipAddr = ( ( ipNum >> 24 ) & 0xFF ) + "." + ( ( ipNum >> 16 ) & 0xFF ) + "." + ( ( ipNum >> 8 ) & 0xFF ) + "." + ( ipNum & 0xFF );

The complete and tested code is mentioned below.

package networking;

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

		// Stores the IP Address
		String ipOctets = "192.168.1.1";

		IpUtil ipUtil = new IpUtil();

		// Convert IP to Number
		long ipNum = ipUtil.ipToNum( ipOctets );

		// Print the number
		System.out.println( "The number of given IP Address : " + ipOctets + " is: " + ipNum );

		// Convert Number back to IP
		ipOctets = ipUtil.numToIp( ipNum );

		// Print the IP
		System.out.println( "The IP Address of given number : " + ipNum + " is: " + ipOctets );
	}

	/**
	 * Convert and return the given IP Octets to number.
	 */

	public long ipToNum( String ip ) {
		long ipNum = -1;

		// IP Octets string array
		String[] octets = ip.split( "\\." );

		// IP Octets integer array
		int[] octetsNum = new int[] {
			Integer.parseInt( octets[ 0 ] ), 
			Integer.parseInt( octets[ 1 ] ),
			Integer.parseInt( octets[ 2 ] ), 
			Integer.parseInt( octets[ 3 ] )
		};

		// IP in numeric form
		ipNum = ( octetsNum[ 0 ] * (int)Math.pow( 256, 3 ) ) + ( octetsNum[ 1 ] * (int)Math.pow( 256, 2 ) ) + ( octetsNum[ 2 ] * 256 ) + ( octetsNum[ 3 ] );

		return ipNum;
	}

	public String numToIp( long ipNum ) {
		// Convert numeric IP to IPv4 Address
		String ipAddr = ( ( ipNum >> 24 ) & 0xFF ) + "." + ( ( ipNum >> 16 ) & 0xFF ) + "." + ( ( ipNum >> 8 ) & 0xFF ) + "." + ( ipNum & 0xFF );

		return ipAddr;
	}
}

The output should be the same as mentioned below.

The number of given IP Address : 192.168.1.1 is: -1062731519
The IP Address of given number : -1062731519 is: 192.168.1.1