InetAddress Class

InetAddress Class

•       The java.net.InetAddress class is Java's encapsulation of an IP address. It is used by most of the other networking classes, including Socket, ServerSocket, URL, DatagramSocket, DatagramPacket, and more.

public final class InetAddress extends Object implements Serializable

•       There are no public constructors in the InetAddress class. However, InetAddress has three static methods that return suitably initialized InetAddress objects, given a little information. They are:

public static InetAddress InetAddress.getByName(String hostName)

throws UnknownHostException public static InetAddress[] InetAddress.getAllByName(String hostName)

throws UnknownHostException public static InetAddress InetAddress.getLocalHost( )

throws UnknownHostException

Example

1. Program that prints the address of www.oreilly.com

import java.net.*;

public class OReillyByName {

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

InetAddress address = InetAddress.getByName("www.oreilly.com");

System.out.println(address);

}

catch (UnknownHostException e) { System.out.println("Could not find www.oreilly.com");

}

}

}

% java OReillyByName www.oreilly.com/204.148.40.9

2. Program that prints the address of 204.148.40.9

import java.net.*;

public class OReillyByAddress {

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

InetAddress address = InetAddress.getByName("204.148.40.9");

System.out.println (address);

}

catch (UnknownHostException e) {

System.out.println ("Could not find 204.148.40.9");

}}}

% java OReillyByAddress helio.ora.com/204.148.40.9

3. Program that prints all the addresses of www.microsoft.com

import java.net.*;

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

try {

InetAddress[] addresses = InetAddress.getAllByName("www.microsoft.com"); for (int i = 0; i < addresses.length; i++) {

System.out.println(addresses[i]);

}

}

catch (UnknownHostException e) {

System.out.println("Could not find www.microsoft.com");

}

}

}

% java AllAddressesOfMicrosoft www.microsoft.com/207.46.131.15 www.microsoft.com/207.46.131.137 www.microsoft.com/207.46.130.14 www.microsoft.com/207.46.130.149 www.microsoft.com/207.46.130.150 www.microsoft.com/207.46.131.13

4. Find the address of the local machine

import java.net.*;

public class MyAddress {

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

InetAddress address = InetAddress.getLocalHost( );

System.out.println(address);

}

catch (UnknownHostException e) {

System.out.println("Could not find this computer's address.");

}

}

}

if ran the program on titan.oit.unc.edu:

% java MyAddress titan.oit.unc.edu/152.2.22.14