NetworkUtils.java

package com.miz.utils;/*
 * Copyright (C) 2014 Michell Bak
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import org.apache.http.conn.util.InetAddressUtils;

import java.net.InetAddress;
import java.net.NetworkInterface;
import java.util.Collections;
import java.util.List;

public class NetworkUtils {

    /**
     * Get IP address from first non-localhost interface.
     * Taken from http://stackoverflow.com/a/13007325/762442.
     * @param useIPv4  true=return ipv4, false=return ipv6
     * @return  address or empty string
     */
    public static String getIPAddress(boolean useIPv4) {
        try {
            List<NetworkInterface> interfaces = Collections.list(NetworkInterface.getNetworkInterfaces());
            for (NetworkInterface intf : interfaces) {
                List<InetAddress> addrs = Collections.list(intf.getInetAddresses());
                for (InetAddress addr : addrs) {
                    if (!addr.isLoopbackAddress()) {
                        String sAddr = addr.getHostAddress().toUpperCase();
                        boolean isIPv4 = InetAddressUtils.isIPv4Address(sAddr);
                        if (useIPv4) {
                            if (isIPv4)
                                return sAddr;
                        } else {
                            if (!isIPv4) {
                                int delim = sAddr.indexOf('%'); // drop ip6 port suffix
                                return delim<0 ? sAddr : sAddr.substring(0, delim);
                            }
                        }
                    }
                }
            }
        } catch (Exception ex) { } // for now eat exceptions
        return "";
    }

}