Java IP Address Get getIp()

Description

get Ip

License

Apache License

Declaration

public static String getIp() 

Method Source Code

//package com.java2s;
//License from project: Apache License 

import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.util.Enumeration;

public class Main {
    private static volatile String cachedIpAddress;

    public static String getIp() {
        if (null != cachedIpAddress) {
            return cachedIpAddress;
        }//from  w w  w  .  ja  va  2  s  .c o  m
        Enumeration<NetworkInterface> netInterfaces;
        try {
            netInterfaces = NetworkInterface.getNetworkInterfaces();
        } catch (final SocketException ex) {
            return "unknown ip";
        }

        String localIpAddress = null;
        while (netInterfaces.hasMoreElements()) {
            NetworkInterface netInterface = netInterfaces.nextElement();
            Enumeration<InetAddress> ipAddresses = netInterface.getInetAddresses();
            while (ipAddresses.hasMoreElements()) {
                InetAddress ipAddress = ipAddresses.nextElement();
                if (isPublicIpAddress(ipAddress)) {
                    String publicIpAddress = ipAddress.getHostAddress();
                    cachedIpAddress = publicIpAddress;
                    return publicIpAddress;
                }
                if (isLocalIpAddress(ipAddress)) {
                    localIpAddress = ipAddress.getHostAddress();
                }
            }
        }
        cachedIpAddress = localIpAddress;
        return localIpAddress;
    }

    private static boolean isPublicIpAddress(final InetAddress ipAddress) {
        return !ipAddress.isSiteLocalAddress() && !ipAddress.isLoopbackAddress() && !isV6IpAddress(ipAddress);
    }

    private static boolean isLocalIpAddress(final InetAddress ipAddress) {
        return ipAddress.isSiteLocalAddress() && !ipAddress.isLoopbackAddress() && !isV6IpAddress(ipAddress);
    }

    private static boolean isV6IpAddress(final InetAddress ipAddress) {
        return ipAddress.getHostAddress().contains(":");
    }
}

Related

1. getInternalIp()
2. getInternetIpAddress()
3. getIntfFromLabelAdva(int n, Inet4Address ip)
4. getIntranetIp()
5. getIP()
6. getIP()
7. getIp()
8. getIp()
9. getIp()