Java Network Interface Get getHostnameFromNetworkInterface()

Description

Returns the host name determined from the network interfaces.

License

Open Source License

Return

the host name, null if none found

Declaration

public static synchronized String getHostnameFromNetworkInterface() 

Method Source Code

//package com.java2s;
/*/*from  w w  w  .  j a v  a 2s. c o  m*/
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU 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 General Public License for more details.
 *
 *   You should have received a copy of the GNU 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.util.ArrayList;
import java.util.Enumeration;
import java.util.List;

public class Main {
    /** host name (from network intf) for faster access. */
    protected static String m_HostnameNetworkInterface;

    /**
     * Returns the host name determined from the network interfaces.
     *
     * @return       the host name, null if none found
     */
    public static synchronized String getHostnameFromNetworkInterface() {
        String result;
        List<String> list;
        Enumeration<NetworkInterface> enmI;
        NetworkInterface intf;
        Enumeration<InetAddress> enmA;
        InetAddress addr;
        boolean found;

        result = null;

        if (m_HostnameNetworkInterface == null) {
            list = new ArrayList<>();
            found = false;
            try {
                enmI = NetworkInterface.getNetworkInterfaces();
                while (enmI.hasMoreElements()) {
                    intf = enmI.nextElement();
                    // skip non-active ones
                    if (!intf.isUp())
                        continue;
                    enmA = intf.getInetAddresses();
                    while (enmA.hasMoreElements()) {
                        addr = enmA.nextElement();
                        list.add(addr.getHostName());
                        if (addr.getHostName().indexOf(':') == -1) {
                            result = addr.getHostName();
                            found = true;
                            break;
                        }
                    }
                    if (found)
                        break;
                }
            } catch (Exception e) {
                // ignored
            }

            if (result == null) {
                if (list.size() > 0)
                    result = list.get(0);
                else
                    result = "<unknown>";
            }

            m_HostnameNetworkInterface = result;
        } else {
            result = m_HostnameNetworkInterface;
        }

        return result;
    }
}

Related

1. getFirstMACAdress()
2. getFreeTunnelInterface()
3. getGlobalI()
4. getGlobalInterfaces()
5. getGoodNetworkInterfaces()
6. getInterface(String ifaceName)
7. getInterfaceByName(String interfaceName)
8. getInterfaceDiagnostic()
9. getInterfaceInfo(NetworkInterface nif)