Java Reference
In-Depth Information
The application
TranslateAddress
, shown next, returns the IP address if
given a host name, or returns the host name if given an IP address:
import java.net.*;
/** Translate IP to a host name or host name to IP
* address. **/
public class
TranslateAddress
{
public static void main (String[] args)
{
// Look for command line argument
if (args.length != 1) {
System.out.println ("Error! No IP or host name
address");
System.out.println (
"Usage: java TranslateAddress java.sun.com");
System.out.println (
" or java TranslateAddress 209.249.116.143");
System.exit (0);
}
try {
// When the argument passed is a host name (e.g.
// sun.com), the corresponding IP address is
// returned. If passed an IP address, then only the
// IP address is returned.
InetAddress address
=
InetAddress.getByName
(args[0]);
System.out.println (
"
Address
"
+ args[0] +
"="
+ address);
// To get the hostname when passed an IP address
// use getHostName(), which will return the host
// name string.
System.out.println ("Name of " + args[0] + "="+
address.getHostName ());
}
catch (UnknownHostException e) {
System.out.println ("Unable to translate the
address.");
}
} // main
} // class TranslateAddress
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