package com.lyp;
import org.apache.commons.lang3.ObjectUtils;
import java.net.*;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
import java.util.Optional;
/**
 * 獲取本機IP 地址
 *
 */
public class IpUtils {
    public static void main(String[] args) throws SocketException, UnknownHostException {
        System.out.println("傳統(tǒng)方式-----------hostAddress = " +getTraditionIp());
        System.out.println( "新方式-----------hostAddress = "+IpUtils.getLocalIp4Address().get().toString().replaceAll("/",""));
    }
    /**
     * 傳統(tǒng)方式，非常簡單直接通過InetAddress獲取，但不準確獲取的為虛擬ip
     * @throws UnknownHostException
     */
    public static String getTraditionIp() throws UnknownHostException {
        InetAddress localHost = InetAddress.getLocalHost();
        String hostAddress = localHost.getHostAddress();
        String hostName = localHost.getHostName();
        return hostAddress;
    }
    /*
     * 獲取本機所有網(wǎng)卡信息   得到所有IP信息
     * @return Inet4Address>
     */
    public static List<Inet4Address> getLocalIp4AddressFromNetworkInterface() throws SocketException {
        List<Inet4Address> addresses = new ArrayList<>(1);
        // 所有網(wǎng)絡(luò)接口信息
        Enumeration<NetworkInterface> networkInterfaces = NetworkInterface.getNetworkInterfaces();
        if (ObjectUtils.isEmpty(networkInterfaces)) {
            return addresses;
        }
        while (networkInterfaces.hasMoreElements()) {
            NetworkInterface networkInterface = networkInterfaces.nextElement();
            //濾回環(huán)網(wǎng)卡、點對點網(wǎng)卡、非活動網(wǎng)卡、虛擬網(wǎng)卡并要求網(wǎng)卡名字是eth或ens開頭
            if (!isValidInterface(networkInterface)) {
                continue;
            }
            // 所有網(wǎng)絡(luò)接口的IP地址信息
            Enumeration<InetAddress> inetAddresses = networkInterface.getInetAddresses();
            while (inetAddresses.hasMoreElements()) {
                InetAddress inetAddress = inetAddresses.nextElement();
                // 判斷是否是IPv4，并且內(nèi)網(wǎng)地址并過濾回環(huán)地址.
                if (isValidAddress(inetAddress)) {
                    addresses.add((Inet4Address) inetAddress);
                }
            }
        }
        return addresses;
    }
    /**
     * 過濾回環(huán)網(wǎng)卡、點對點網(wǎng)卡、非活動網(wǎng)卡、虛擬網(wǎng)卡并要求網(wǎng)卡名字是eth或ens開頭
     *
     * @param ni 網(wǎng)卡
     * @return 如果滿足要求則true，否則false
     */
    private static boolean isValidInterface(NetworkInterface ni) throws SocketException {
        return !ni.isLoopback() && !ni.isPointToPoint() && ni.isUp() && !ni.isVirtual()
                && (ni.getName().startsWith("eth") || ni.getName().startsWith("ens"));
    }
    /**
     * 判斷是否是IPv4，并且內(nèi)網(wǎng)地址并過濾回環(huán)地址.
     */
    private static boolean isValidAddress(InetAddress address) {
        return address instanceof Inet4Address && address.isSiteLocalAddress() && !address.isLoopbackAddress();
    }
    /*
     * 通過Socket 唯一確定一個IP
     * 當有多個網(wǎng)卡的時候，使用這種方式一般都可以得到想要的IP。甚至不要求外網(wǎng)地址8.8.8.8是可連通的
     * @return Inet4Address>
     */
    private static Optional<Inet4Address> getIpBySocket() throws SocketException {
        try (final DatagramSocket socket = new DatagramSocket()) {
            socket.connect(InetAddress.getByName("8.8.8.8"), 10002);
            if (socket.getLocalAddress() instanceof Inet4Address) {
                return Optional.of((Inet4Address) socket.getLocalAddress());
            }
        } catch (UnknownHostException networkInterfaces) {
            throw new RuntimeException(networkInterfaces);
        }
        return Optional.empty();
    }
    /*
     * 獲取本地IPv4地址
     * @return Inet4Address>
     */
    public static Optional<Inet4Address> getLocalIp4Address() throws SocketException {
        final List<Inet4Address> inet4Addresses = getLocalIp4AddressFromNetworkInterface();
        if (inet4Addresses.size() != 1) {
            final Optional<Inet4Address> ipBySocketOpt = getIpBySocket();
            if (ipBySocketOpt.isPresent()) {
                return ipBySocketOpt;
            } else {
                return inet4Addresses.isEmpty() ? Optional.empty() : Optional.of(inet4Addresses.get(0));
            }
        }
        return Optional.of(inet4Addresses.get(0));
    }
}