Replies the first IPv4 public address. - Java Network

Java examples for Network:Network Address

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Description

Replies the first IPv4 public address.

Demo Code

/*//from ww w. ja va 2 s  .  c o  m
 * $Id$
 *
 * Janus platform is an open-source multiagent platform.
 * More details on http://www.janusproject.io
 *
 * Copyright (C) 2014 Sebastian RODRIGUEZ, Nicolas GAUD, St?phane GALLAND.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
//package com.java2s;

import java.net.Inet4Address;
import java.net.InetAddress;

import java.net.NetworkInterface;
import java.net.SocketException;

import java.util.Enumeration;

public class Main {
    /**
     * Replies the first IPv4 public address.
     * A public address is an address that is not loopback.
     *
     * @return the first public IPv4 address or <code>null</code> if
     * none.
     */
    public static InetAddress getPrimaryAddress() {
        try {
            Enumeration<NetworkInterface> interfaces = NetworkInterface
                    .getNetworkInterfaces();
            if (interfaces != null) {
                NetworkInterface inter;
                InetAddress adr;
                Enumeration<InetAddress> addrs;
                while (interfaces.hasMoreElements()) {
                    inter = interfaces.nextElement();
                    addrs = inter.getInetAddresses();
                    if (addrs != null) {
                        while (addrs.hasMoreElements()) {
                            adr = addrs.nextElement();
                            if (adr != null && !adr.isLoopbackAddress()
                                    && (adr instanceof Inet4Address)) {
                                return adr;
                            }
                        }
                    }
                }
            }
        } catch (SocketException e) {
            //
        }
        return null;
    }
}

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