先获得百度API秘钥和查询连接 --》 https://blog.csdn.net/weixin_45395810/article/details/100779263

工具类：

1. 获得客户端ip

import javax.servlet.http.HttpServletRequest;
import java.net.InetAddress;
import java.net.UnknownHostException;
 
/**
 * @Author : JCccc
 * @CreateTime : 2018-11-23
 * @Description :
 * @Point: Keep a good mood
 **/
public class IpUtil {
    public static String getIpAddr(HttpServletRequest request) {
        String ipAddress = null;
        try {
            ipAddress = request.getHeader("x-forwarded-for");
            if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
                ipAddress = request.getHeader("Proxy-Client-IP");
            }
            if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
                ipAddress = request.getHeader("WL-Proxy-Client-IP");
            }
            if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
                ipAddress = request.getRemoteAddr();
                if (ipAddress.equals("127.0.0.1")) {
                    // 根据网卡取本机配置的IP
                    InetAddress inet = null;
                    try {
                        inet = InetAddress.getLocalHost();
                    } catch (UnknownHostException e) {
                        e.printStackTrace();
                    }
                    ipAddress = inet.getHostAddress();
                }
            }
            // 对于通过多个代理的情况，第一个IP为客户端真实IP,多个IP按照','分割
            if (ipAddress != null && ipAddress.length() > 15) { // "***.***.***.***".length()
                // = 15
                if (ipAddress.indexOf(",") > 0) {
                    ipAddress = ipAddress.substring(0, ipAddress.indexOf(","));
                }
            }
        } catch (Exception e) {
            ipAddress="";
        }
        // ipAddress = this.getRequest().getRemoteAddr();
 
        return ipAddress;
    }
}

2. 根据ip访问网址，获得城市

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.URL;
import java.nio.charset.Charset;

import com.fasterxml.jackson.annotation.JsonAlias;
import org.json.JSONException;
import org.json.JSONObject;

import javax.servlet.http.HttpServletRequest;

/**
 * java根据url获取json对象
 *
 * @author openks
 * @since 2013-7-16
 * 需要添加java-json.jar才能运行
 */
public class GetPlaceByIp {

    private static String readAll(Reader rd) throws IOException {
        StringBuilder sb = new StringBuilder();
        int cp;
        while ((cp = rd.read()) != -1) {
            sb.append((char) cp);
        }
        return sb.toString();
    }

    public static JSONObject readJsonFromUrl(String url) throws IOException, JSONException {
        InputStream is = new URL(url).openStream();
        try {
            BufferedReader rd = new BufferedReader(new InputStreamReader(is, Charset.forName("UTF-8")));
            String jsonText = readAll(rd);
            JSONObject json = new JSONObject(jsonText);
            return json;
        } finally {
            is.close();
            // System.out.println("同时 从这里也能看出 即便return了，仍然会执行finally的！");
        }
    }

    public static String getPlace(HttpServletRequest request) throws IOException, JSONException {
        String ip = IpUtil.getIpAddr(request);
        if (ip.equals("0:0:0:0:0:0:0:1")){
            ip = "";//如果本机地址，ip设为空
        }
        String url = "https://api.map.baidu.com/location/ip?ip=" + ip + "&ak=你的AK&coor=bd09ll";
        JSONObject jsonObject = readJsonFromUrl(url);
        System.out.println(jsonObject.toString());
        String place = (String) ((JSONObject) jsonObject.get("content")).get("address");
        System.out.println(place);
        return place;
    }
}

测试