Here you can find the source of getInternalIp()
| Parameter | Description |
|---|---|
| Exception | an exception |
public static String getInternalIp() throws Exception
//package com.java2s; /*/*from w w w . j a v a2 s. co m*/ * * Copyright (C) 2013 * * This file is part of Messic. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation, either version 3 of * the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ import java.net.InetAddress; import java.net.NetworkInterface; import java.net.UnknownHostException; import java.util.Enumeration; public class Main { /** * Get the internal IP of the machine where is launched Messic * * @return * @throws Exception */ public static String getInternalIp() throws Exception { InetAddress thisIp = getLocalHostLANAddress(); return thisIp.getHostAddress().toString(); } /** * Returns an <code>InetAddress</code> object encapsulating what is most likely the machine's LAN IP address. * <p/> * This method is intended for use as a replacement of JDK method <code>InetAddress.getLocalHost</code>, because * that method is ambiguous on Linux systems. Linux systems enumerate the loopback network interface the same way as * regular LAN network interfaces, but the JDK <code>InetAddress.getLocalHost</code> method does not specify the * algorithm used to select the address returned under such circumstances, and will often return the loopback * address, which is not valid for network communication. Details <a * href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4665037">here</a>. * <p/> * This method will scan all IP addresses on all network interfaces on the host machine to determine the IP address * most likely to be the machine's LAN address. If the machine has multiple IP addresses, this method will prefer a * site-local IP address (e.g. 192.168.x.x or 10.10.x.x, usually IPv4) if the machine has one (and will return the * first site-local address if the machine has more than one), but if the machine does not hold a site-local * address, this method will return simply the first non-loopback address found (IPv4 or IPv6). * <p/> * If this method cannot find a non-loopback address using this selection algorithm, it will fall back to calling * and returning the result of JDK method <code>InetAddress.getLocalHost</code>. * <p/> * * @throws UnknownHostException If the LAN address of the machine cannot be found. */ private static InetAddress getLocalHostLANAddress() throws UnknownHostException { try { InetAddress candidateAddress = null; // Iterate all NICs (network interface cards)... for (Enumeration ifaces = NetworkInterface.getNetworkInterfaces(); ifaces.hasMoreElements();) { NetworkInterface iface = (NetworkInterface) ifaces.nextElement(); // Iterate all IP addresses assigned to each card... for (Enumeration inetAddrs = iface.getInetAddresses(); inetAddrs.hasMoreElements();) { InetAddress inetAddr = (InetAddress) inetAddrs.nextElement(); if (!inetAddr.isLoopbackAddress()) { if (inetAddr.isSiteLocalAddress()) { // Found non-loopback site-local address. Return it immediately... return inetAddr; } else if (candidateAddress == null) { // Found non-loopback address, but not necessarily site-local. // Store it as a candidate to be returned if site-local address is not subsequently found... candidateAddress = inetAddr; // Note that we don't repeatedly assign non-loopback non-site-local addresses as candidates, // only the first. For subsequent iterations, candidate will be non-null. } } } } if (candidateAddress != null) { // We did not find a site-local address, but we found some other non-loopback address. // Server might have a non-site-local address assigned to its NIC (or it might be running // IPv6 which deprecates the "site-local" concept). // Return this non-loopback candidate address... return candidateAddress; } // At this point, we did not find a non-loopback address. // Fall back to returning whatever InetAddress.getLocalHost() returns... InetAddress jdkSuppliedAddress = InetAddress.getLocalHost(); if (jdkSuppliedAddress == null) { throw new UnknownHostException( "The JDK InetAddress.getLocalHost() method unexpectedly returned null."); } return jdkSuppliedAddress; } catch (Exception e) { UnknownHostException unknownHostException = new UnknownHostException( "Failed to determine LAN address: " + e); unknownHostException.initCause(e); throw unknownHostException; } } }