Java獲得系統的外網IP

關於如何獲得系統外網IP？在網上找了好久，大多數解決方案都沒法直接用，所以今天和大家分享一段獲得外網IP的代碼！

 

import java.net.Inet4Address;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.util.Enumeration;

/**
 * 系統工具類，用於獲取系統相關信息
 * Created by kagome.
 */
public class CustomSystemUtil {
    public static String INTRANET_IP = getIntranetIp(); // 內網IP
    public static String INTERNET_IP = getInternetIp(); // 外網IP

    private CustomSystemUtil(){}

    /**
     * 獲得內網IP
     * @return 內網IP
     */
    private static String getIntranetIp(){
        try{
            return InetAddress.getLocalHost().getHostAddress();
        } catch(Exception e){
            throw new RuntimeException(e);
        }
    }

    /**
     * 獲得外網IP
     * @return 外網IP
     */
    private static String getInternetIp(){
        try{
            Enumeration<NetworkInterface> networks = NetworkInterface.getNetworkInterfaces();
            InetAddress ip = null;
            Enumeration<InetAddress> addrs;
            while (networks.hasMoreElements())
            {
                addrs = networks.nextElement().getInetAddresses();
                while (addrs.hasMoreElements())
                {
                    ip = addrs.nextElement();
                    if (ip != null
                            && ip instanceof Inet4Address
                            && ip.isSiteLocalAddress()
                            && !ip.getHostAddress().equals(INTRANET_IP))
                    {
                        return ip.getHostAddress();
                    }
                }
            }

            // 如果沒有外網IP，就返回內網IP
            return INTRANET_IP;
        } catch(Exception e){
            throw new RuntimeException(e);
        }
    }
}