一. 除了调用接口查询城市, 还可以通过离线文件查询城市, 使用GeoLite2 City库

二. 离线库下载地址: https://dev.maxmind.com/geoip/geoip2/geolite2/ 点击如下位置下载压缩文件

文件解压后有一个文件名为GeoLite2-City.mmdb, 这就是我们的离线库

三. 导包

<dependency>
    <groupId>com.maxmind.geoip2</groupId>
    <artifactId>geoip2</artifactId>
    <version>2.8.1</version>
</dependency>

四. 编写工具类

package com.product.utils;

import java.net.InetAddress;

import javax.servlet.http.HttpServletRequest;

import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.maxmind.geoip2.DatabaseReader;

/**
 * 
 * @description: 获取客户端IP地址
 * @author: paulandcode
 * @email: paulandcode@gmail.com
 * @since: 2018年9月17日 下午3:44:51
 */
public class IPUtils {
    private static Logger logger = LoggerFactory.getLogger(IPUtils.class);

    /**
     * 获取客户端IP地址
     * 
     * 使用Nginx等反向代理软件， 则不能通过request.getRemoteAddr()获取IP地址
     * 如果使用了多级反向代理的话，X-Forwarded-For的值并不止一个，而是一串IP地址，X-Forwarded-For中第一个非unknown的有效IP字符串，则为真实IP地址
     */
    public static String getIP(HttpServletRequest request) {
        String ip = null;
        try {
            ip = request.getHeader("x-forwarded-for");
            if (StringUtils.isEmpty(ip) || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("Proxy-Client-IP");
            }
            if (StringUtils.isEmpty(ip) || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("WL-Proxy-Client-IP");
            }
            if (StringUtils.isEmpty(ip) || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("HTTP_CLIENT_IP");
            }
            if (StringUtils.isEmpty(ip) || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("HTTP_X_FORWARDED_FOR");
            }
            if (StringUtils.isEmpty(ip) || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getRemoteAddr();
            }
        } catch (Exception e) {
            logger.error("IPUtils ERROR ", e);
        }
        return ip;
    }

    /**
     * 
     * @description: 获得国家 
     * @param reader
     * @param ip
     * @return
     * @throws Exception
     */
    public static String getCountry(DatabaseReader reader, String ip) throws Exception {
        return reader.city(InetAddress.getByName(ip)).getCountry().getNames().get("zh-CN");
    }

    /**
     * 
     * @description: 获得省份 
     * @param reader
     * @param ip
     * @return
     * @throws Exception
     */
    public static String getProvince(DatabaseReader reader, String ip) throws Exception {
        return reader.city(InetAddress.getByName(ip)).getMostSpecificSubdivision().getNames().get("zh-CN");
    }

    /**
     * 
     * @description: 获得城市 
     * @param reader
     * @param ip
     * @return
     * @throws Exception
     */
    public static String getCity(DatabaseReader reader, String ip) throws Exception {
        return reader.city(InetAddress.getByName(ip)).getCity().getNames().get("zh-CN");
    }
    
    /**
     * 
     * @description: 获得经度 
     * @param reader
     * @param ip
     * @return
     * @throws Exception
     */
    public static Double getLongitude(DatabaseReader reader, String ip) throws Exception {
        return reader.city(InetAddress.getByName(ip)).getLocation().getLongitude();
    }
    
    /**
     * 
     * @description: 获得纬度
     * @param reader
     * @param ip
     * @return
     * @throws Exception
     */
    public static Double getLatitude(DatabaseReader reader, String ip) throws Exception {
        return reader.city(InetAddress.getByName(ip)).getLocation().getLatitude();
    }
}

五. main方法测试

// String path = req.getSession().getServletContext().getRealPath("/WEB-INF/classes/GeoLite2-City.mmdb");
String path = "E:/GeoLite2-City.mmdb";
// 创建 GeoLite2 数据库
File database = new File(path);
// 读取数据库内容
DatabaseReader reader = new DatabaseReader.Builder(database).build();
// 访问IP
String ip = "36.157.208.62";
String site = IPUtils.getCountry(reader, ip) + "-" + IPUtils.getProvince(reader, ip) + "-" + IPUtils.getCity(reader, ip);
System.out.println(site);