Java Local Address Get getLocalAddress()

Description

get Local Address

License

Apache License

Declaration

public static String getLocalAddress() 

Method Source Code

//package com.java2s;
/**/*w  ww .  j  a  v  a2 s  .  c  o m*/
 * Copyright (C) 2010-2013 Alibaba Group Holding Limited
 *
 * 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.
 */

import java.net.*;

import java.util.ArrayList;
import java.util.Enumeration;

public class Main {
    public static String getLocalAddress() {
        try {
            // Traversal Network interface to get the first non-loopback and non-private address
            Enumeration<NetworkInterface> enumeration = NetworkInterface.getNetworkInterfaces();
            ArrayList<String> ipv4Result = new ArrayList<String>();
            ArrayList<String> ipv6Result = new ArrayList<String>();
            while (enumeration.hasMoreElements()) {
                final NetworkInterface networkInterface = enumeration.nextElement();
                final Enumeration<InetAddress> en = networkInterface.getInetAddresses();
                while (en.hasMoreElements()) {
                    final InetAddress address = en.nextElement();
                    if (!address.isLoopbackAddress()) {
                        if (address instanceof Inet6Address) {
                            ipv6Result.add(normalizeHostAddress(address));
                        } else {
                            ipv4Result.add(normalizeHostAddress(address));
                        }
                    }
                }
            }

            // prefer ipv4
            if (!ipv4Result.isEmpty()) {
                for (String ip : ipv4Result) {
                    if (ip.startsWith("127.0") || ip.startsWith("192.168")) {
                        continue;
                    }

                    return ip;
                }

                return ipv4Result.get(ipv4Result.size() - 1);
            } else if (!ipv6Result.isEmpty()) {
                return ipv6Result.get(0);
            }
            //If failed to find,fall back to localhost
            final InetAddress localHost = InetAddress.getLocalHost();
            return normalizeHostAddress(localHost);
        } catch (SocketException e) {
            e.printStackTrace();
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }

        return null;
    }

    public static String normalizeHostAddress(final InetAddress localHost) {
        if (localHost instanceof Inet6Address) {
            return "[" + localHost.getHostAddress() + "]";
        } else {
            return localHost.getHostAddress();
        }
    }
}

Related

1. getLocalAddress()
2. getLocalAddress()
3. getLocalAddress()
4. getLocalAddress()
5. getLocalAddress()
6. getLocalAddress()
7. getLocalAddress(final String start, final String end)
8. getLocalAddress(int port)
9. getLocalAddress(int port)