Java Local Host Get getLocalHostName()

Description

Retrieves the local host's hostname.

License

Apache License

Declaration

public static String getLocalHostName() throws SocketException, UnknownHostException 

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.net.UnknownHostException;

public class Main {
    private static final String REGEX_IP_ADDRESS = "\\d+(\\.\\d+){3}";

    /**//w  w  w .  j  a  v  a 2 s . co m
     * Retrieves the local host's hostname. If found, the fully qualified domain name (FQDN) will be returned,
     * otherwise it will fallback to the unqualified domain name. E.g prefer guerrero.moocar.me over guerrero.
     */
    public static String getLocalHostName() throws SocketException, UnknownHostException {
        try {
            final String canonicalHostName = InetAddress.getLocalHost().getCanonicalHostName();
            if (isFQDN(canonicalHostName)) {
                return canonicalHostName;
            } else {
                return InetAddress.getLocalHost().getHostName();
            }
        } catch (UnknownHostException e) {
            NetworkInterface networkInterface = NetworkInterface.getNetworkInterfaces().nextElement();
            if (networkInterface == null)
                throw e;
            InetAddress ipAddress = networkInterface.getInetAddresses().nextElement();
            if (ipAddress == null)
                throw e;
            return ipAddress.getHostAddress();
        }
    }

    /**
     * Returns true is the hostname is a Fully Qualified Domain Name (FQDN)
     */
    private static boolean isFQDN(String hostname) {
        return hostname.contains(".") && !hostname.matches(REGEX_IP_ADDRESS);
    }
}

Related

1. getLocalHostName()
2. getLocalHostName()
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9. getLocalHostName(boolean includeDomain)