InetAddress.getLocalHost（）在linux中抛出unknownHostException

String host = null;
NetworkInterface iface = null;

        for(Enumeration<NetworkInterface> ifaces = NetworkInterface.getNetworkInterfaces();ifaces.hasMoreElements();){
                   iface = (NetworkInterface)ifaces.nextElement();
                   InetAddress ia = null;
                    for(Enumeration<InetAddress> ips = iface.getInetAddresses();ips.hasMoreElements();){
                    ia = (InetAddress)ips.nextElement();
                    if(!ia.isLoopbackAddress() && (!ia.isLinkLocalAddress()) && (ia instanceof Inet4Address)) host=ia.getHostAddress();
                    }
                  }