獲取當前IP地址的Java代碼實現

獲取當前IP地址是Java開發中常見需求之一，本文將從以下多個方面對獲取當前IP地址的Java代碼實現做詳細的闡述。

一、使用Inet4Address獲取當前IP地址

Inet4Address是Java中一個用於表示IPv4地址的類，可以通過該類獲取當前主機的IP地址。

import java.net.InetAddress;
import java.net.UnknownHostException;

public class InetAddressUtil {
    public static void main(String[] args) throws UnknownHostException {
        InetAddress inetAddress = InetAddress.getLocalHost();
        System.out.println("當前IP地址為：" + inetAddress.getHostAddress());
    }
}

通過調用getHostAddress()方法即可獲取當前主機的IP地址。

二、使用NetworkInterface獲取當前IP地址

除了Inet4Address，還可以使用Java提供的NetworkInterface類獲取當前主機的IP地址。

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

public class NetworkInterfaceUtil {
    public static void main(String[] args) throws SocketException {
        Enumeration networkInterfaces = NetworkInterface.getNetworkInterfaces();
        while (networkInterfaces.hasMoreElements()) {
            NetworkInterface networkInterface = networkInterfaces.nextElement();
            Enumeration inetAddresses = networkInterface.getInetAddresses();
            while (inetAddresses.hasMoreElements()) {
                InetAddress inetAddress = inetAddresses.nextElement();
                System.out.println("當前IP地址為：" + inetAddress.getHostAddress());
            }
        }
    }
}

通過NetworkInterface獲取所有的網絡接口，再通過網絡接口獲取所有的IP地址。

三、使用HttpClient發送GET請求獲取當前IP地址

除了使用Java自帶的類獲取IP地址，還可以通過HttpClient發送GET請求獲取當前主機的IP地址。

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

import java.io.IOException;

public class HttpClientUtil {
    public static void main(String[] args) throws IOException {
        HttpClient httpClient = HttpClients.createDefault();
        HttpGet httpGet = new HttpGet("http://myip.ipip.net/");
        HttpResponse httpResponse = httpClient.execute(httpGet);
        HttpEntity httpEntity = httpResponse.getEntity();
        String result = EntityUtils.toString(httpEntity);
        String ip = result.substring(result.indexOf("[") + 1, result.indexOf("]"));
        System.out.println("當前IP地址為：" + ip);
    }
}

通過發送GET請求至http://myip.ipip.net/，並從返回結果中解析出當前主機的IP地址。

四、使用Java獲取其它網絡信息

除了獲取當前IP地址，還可以使用Java獲取其它網絡信息，例如：本機的MAC地址、域名、端口等。

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

public class NetworkInfoUtil {
    public static void main(String[] args) throws UnknownHostException {
        InetAddress inetAddress = InetAddress.getLocalHost();
        System.out.println("當前主機名為：" + inetAddress.getHostName());
        System.out.println("當前主機的IP地址為：" + inetAddress.getHostAddress());

        Enumeration networkInterfaces = NetworkInterface.getNetworkInterfaces();

        while (networkInterfaces.hasMoreElements()) {
            NetworkInterface networkInterface = (NetworkInterface) networkInterfaces.nextElement();
            byte[] macBytes = networkInterface.getHardwareAddress();
            if (macBytes != null) {
                StringBuilder sb = new StringBuilder();
                for (int i = 0; i < macBytes.length; i++) {
                    sb.append(String.format("%02X%s", macBytes[i], (i < macBytes.length - 1) ? "-" : ""));
                }
                System.out.println("當前主機的MAC地址為：" + sb.toString());
            }

            Enumeration inetAddresses = networkInterface.getInetAddresses();
            while (inetAddresses.hasMoreElements()) {
                InetAddress address = (InetAddress) inetAddresses.nextElement();
                System.out.println("當前主機的域名為：" + address.getHostName());
                System.out.println("當前主機的端口號為：" + networkInterface.getMTU());
            }
        }
    }
}

通過調用相應的方法即可獲取相應的網絡信息。

總結

本文從使用Inet4Address獲取IP地址、使用NetworkInterface獲取IP地址、使用HttpClient發送GET請求獲取IP地址、使用Java獲取其它網絡信息等多個方面對獲取當前IP地址的Java代碼實現進行了詳細的闡述。在實際開發中，可以根據需求選擇相應的方式來獲取IP地址。