回复第一个IPv4公共地址。

/*

 * $Id$

 *

 * Janus platform is an open-source multiagent platform.

 * More details on http://www.janusproject.io

 *

 * Copyright (C) 2014 Sebastian RODRIGUEZ, Nicolas GAUD, St?phane GALLAND.

 *

 * 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.

 */

//package com.nowjava;

/* 
*来 自
 N o w J a v a . c o m - 时代Java
*/

import java.net.Inet4Address;

import java.net.InetAddress;


import java.net.NetworkInterface;

import java.net.SocketException;


import java.util.Enumeration;


public class Main {

    /**

     * Replies the first IPv4 public address.

     * A public address is an address that is not loopback.

     *

     * @return the first public IPv4 address or <code>null</code> if

     * none.

     */

    public static InetAddress getPrimaryAddress() {

        try {
        /* from 
        nowjava*/

            Enumeration<NetworkInterface> interfaces = NetworkInterface

                    .getNetworkInterfaces();

            if (interfaces != null) {

                NetworkInterface inter;

                InetAddress adr;

                Enumeration<InetAddress> addrs;

                while (interfaces.hasMoreElements()) {

                    inter = interfaces.nextElement();

                    addrs = inter.getInetAddresses();

                    if (addrs != null) {

                        while (addrs.hasMoreElements()) {

                            adr = addrs.nextElement();

                            if (adr != null && !adr.isLoopbackAddress()