JAVA获取本地外网IP

最近搞物联网平台，发现终端的设备在插拔网线之后，IP发生了改变导致，平台无法连接，遂想出个办法，在终端执行一个定时任务发送终端IP到服务平台，

下面是通过java获取外网IP的程序。

package com.fan.study.ip;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class IPUtil {
    public static void main(String[] args) throws IOException {
        System.out.println(IPUtil.getIP());
    }
    /**
     * @Param 
     * @Description 获取IP
     * @Date: 2021/5/11
     **/
    public static String getIP() throws IOException {
        String ip = null;
        String chinaZ = "http://ip.chinaz.com";
        String response = sendGet(chinaZ);
        //过滤出响应中外网IP
        ip = match(response, "\\<dd class\\=\"fz24\">(.*?)\\<\\/dd>");
        if (ip == null) {
            String newUrl = match(response, "window.location.href=\"(http://ip.chinaz.com.+)\"");
            response = sendGet(newUrl);
            ip = match(response, "\\<dd class\\=\"fz24\">(.*?)\\<\\/dd>");
        } 
        return ip;
    }
    /**
     * @Param str
     * @Param regex
     * @Description 正则过滤
     * @Date: 2021/5/11
     **/
    public static String match(String str, String regex) {
        Pattern p = Pattern.compile(regex);
        Matcher m = p.matcher(str);
        if (m.find()) {
            return m.group(1);
        }
        return null;
    }
    /**
     * @Param url
     * @Description 发送get请求
     * @Date: 2021/5/11
     **/
    public static String sendGet(String url) throws IOException {
        URL urlObject = new URL(url);
        HttpURLConnection connection = (HttpURLConnection) urlObject.openConnection();
        connection.connect();
        try (InputStream inputStream = connection.getInputStream();
             BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream))) {
            StringBuilder response = new StringBuilder();
            String str;
            while ((str = reader.readLine()) != null) {
                response.append(str);
            }
            return response.toString();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
        return null;
    }
}