我们在刷微博，抖音、B站的时候，在每个评论下面会显示网络用户所在地。国内的用户显示的是省份，国外的用户显示是国家。公开显示网络用户所在地可以提醒用户谨慎发言、治理水军、减少冒充当事人等现象。

那么，这个功能是怎么实现的呢？

Java 中获取 IP 归属地，主要是分为以下两步：

• 1>通过 HttpServletRequest 获取 Ip
• 2>根据 IP 查询获取对应的归属地

下面我们详细讲解2部内容。

1、通过HttpServletRequest 获取 IP

public class IpUtil {

    private static final String UNKNOWN = "unknown";
    private static final String HEADER_FORWARDED = "x-forwarded-for";
    private static final String HEADER_PROXY = "Proxy-Client-IP";
    private static final String HEADER_WL_PROXY = "WL-Proxy-Client-IP";
    private static final String HEADER_HTTP = "HTTP_CLIENT_IP";
    private static final String HEADER_HTTP_FORWARDED = "HTTP_X_FORWARDED_FOR";
    private static final String LOCAL_IP = "127.0.0.1";
    private static final String LOCAL_HOST = "localhost";

    /**
     * 获取 IP 地址
     *
     * @param request
     * @return
     */
    public String getIpAddr(HttpServletRequest request) {
        String ip = request.getHeader(HEADER_FORWARDED);

        if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
            ip = request.getHeader(HEADER_PROXY);
        }

        if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
            ip = request.getHeader(HEADER_WL_PROXY);
        }

        if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
            ip = request.getHeader(HEADER_HTTP);
        }

        if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
            ip = request.getHeader(HEADER_HTTP_FORWARDED);
        }

        if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
            ip = request.getRemoteAddr();
        }

        // 本机访问
        if (LOCAL_IP.equalsIgnoreCase(ip) || LOCAL_HOST.equalsIgnoreCase(ip) || "0:0:0:0:0:0:0:1".equalsIgnoreCase(ip)) {
            // 根据网卡取本机配置的 IP
            try {
                InetAddress localHost = InetAddress.getLocalHost();
                ip = localHost.getHostAddress();
            } catch (UnknownHostException e) {
                e.printStackTrace();
            }
        }

        // 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 (ip != null && ip.length() > 15) {
            if (ip.indexOf(",") > 15) {
                ip = ip.substring(0, ip.indexOf(","));
            }
        }

        return ip;
    }
}

2、根据 IP 查询获取对应的归属地

2.1、第一种实现，参照百度方式实现。

此种会返回json格式:

{"regionCode":"0","regionNames":"","proCode":"510000","err":"","city":"成都市","cityCode":"510100","ip":"218.88.83.8","pro":"四川省","region":"","addr":"四川省成都市 电信"}

具体代码实现为:

import com.alibaba.fastjson.JSONObject;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;


public class AddressUtils {

    // IP地址查询
    public static final String IP_URL = "http://whois.pconline.com.cn/ipJson.jsp";

    // 未知地址
    public static final String UNKNOWN = "XX XX";

    public static void main(String[] args) {
        System.out.println(getRealAddressByIP("218.88.83.8"));
    }

    public static String getRealAddressByIP(String ip) {
        // 内网不查询
        if (internalIp(ip)) {
            return "内网IP";
        }

        try {
            String rspStr = sendGet(IP_URL, "ip=" + ip + "&json=true", "GBK");
            if ("".equals(rspStr)) {
                return UNKNOWN;
            }
            JSONObject obj = JSONObject.parseObject(rspStr);
            return obj.toJSONString();
        } catch (Exception e) {
            e.printStackTrace();
        }

        return UNKNOWN;
    }



    public static boolean internalIp(String ip) {
        byte[] addr = textToNumericFormatV4(ip);
        return internalIp(addr) || "127.0.0.1".equals(ip);
    }

    private static boolean internalIp(byte[] addr) {
        if (addr == null || addr.length < 2) {
            return true;
        }
        final byte b0 = addr[0];
        final byte b1 = addr[1];
        // 10.x.x.x/8
        final byte SECTION_1 = 0x0A;
        // 172.16.x.x/12
        final byte SECTION_2 = (byte) 0xAC;
        final byte SECTION_3 = (byte) 0x10;
        final byte SECTION_4 = (byte) 0x1F;
        // 192.168.x.x/16
        final byte SECTION_5 = (byte) 0xC0;
        final byte SECTION_6 = (byte) 0xA8;
        switch (b0) {
            case SECTION_1:
                return true;
            case SECTION_2:
                if (b1 >= SECTION_3 && b1 <= SECTION_4) {
                    return true;
                }
            case SECTION_5:
                if (b1 == SECTION_6) {
                    return true;
                }
            default:
                return false;
        }
    }
    /**
     * 将IPv4地址转换成字节
     *
     * @param text IPv4地址
     * @return byte 字节
     */
    public static byte[] textToNumericFormatV4(String text) {
        if (text.length() == 0) {
            return null;
        }

        byte[] bytes = new byte[4];
        String[] elements = text.split("\\.", -1);
        try {
            long l;
            int i;
            switch (elements.length) {
                case 1:
                    l = Long.parseLong(elements[0]);
                    if ((l < 0L) || (l > 4294967295L)) {
                        return null;
                    }
                    bytes[0] = (byte) (int) (l >> 24 & 0xFF);
                    bytes[1] = (byte) (int) ((l & 0xFFFFFF) >> 16 & 0xFF);
                    bytes[2] = (byte) (int) ((l & 0xFFFF) >> 8 & 0xFF);
                    bytes[3] = (byte) (int) (l & 0xFF);
                    break;
                case 2:
                    l = Integer.parseInt(elements[0]);
                    if ((l < 0L) || (l > 255L)) {
                        return null;
                    }
                    bytes[0] = (byte) (int) (l & 0xFF);
                    l = Integer.parseInt(elements[1]);
                    if ((l < 0L) || (l > 16777215L)) {
                        return null;
                    }
                    bytes[1] = (byte) (int) (l >> 16 & 0xFF);
                    bytes[2] = (byte) (int) ((l & 0xFFFF) >> 8 & 0xFF);
                    bytes[3] = (byte) (int) (l & 0xFF);
                    break;
                case 3:
                    for (i = 0; i < 2; ++i) {
                        l = Integer.parseInt(elements[i]);
                        if ((l < 0L) || (l > 255L)) {
                            return null;
                        }
                        bytes[i] = (byte) (int) (l & 0xFF);
                    }
                    l = Integer.parseInt(elements[2]);
                    if ((l < 0L) || (l > 65535L)) {
                        return null;
                    }
                    bytes[2] = (byte) (int) (l >> 8 & 0xFF);
                    bytes[3] = (byte) (int) (l & 0xFF);
                    break;
                case 4:
                    for (i = 0; i < 4; ++i) {
                        l = Integer.parseInt(elements[i]);
                        if ((l < 0L) || (l > 255L)) {
                            return null;
                        }
                        bytes[i] = (byte) (int) (l & 0xFF);
                    }
                    break;
                default:
                    return null;
            }
        } catch (NumberFormatException e) {
            return null;
        }
        return bytes;
    }


  
  /**
     * 向指定 URL 发送GET方法的请求
     *
     * @param url 发送请求的 URL
     * @param param 请求参数，请求参数应该是 name1=value1&name2=value2 的形式。
     * @param contentType 编码类型
     * @return 所代表远程资源的响应结果
     */
    public static String sendGet(String url, String param, String contentType) {
        StringBuilder result = new StringBuilder();
        BufferedReader in = null;
        try {
            String urlNameString = url + "?" + param;
            URL realUrl = new URL(urlNameString);
            URLConnection connection = realUrl.openConnection();
            connection.setRequestProperty("accept", "*/*");
            connection.setRequestProperty("connection", "Keep-Alive");
            connection.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            connection.connect();
            in = new BufferedReader(new InputStreamReader(connection.getInputStream(), contentType));
            String line;
            while ((line = in.readLine()) != null) {
                result.append(line);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        finally {
            try {
                if (in != null) {
                    in.close();
                }
            }
            catch (Exception ex) {
                ex.printStackTrace();
            }
        }
        return result.toString();
    }
}

2.2、第二种实现

根据ip获取对应的归属地的写法很多以及第三方jar也很多，这里我们使用Ip2region第三方jar包。

据官网介绍，Ip2region的极速查询响应即使是完全基于 xdb 文件的查询，单次查询响应时间在十微秒级别。

引入依赖

<dependency>
    <groupId>org.lionsoul</groupId>
    <artifactId>ip2region</artifactId>
    <version>2.6.5</version>
</dependency>

下载 ip2region.xdb

下载地址为:

https://gitee.com/lionsoul/ip2region/blob/master/data/ip2region.xdb

编写工具类

public class IpUtil {

    private static Searcher searcher;

    /**
     * 判断是否为合法 IP
     * @return
     */
    public static boolean checkIp(String ipAddress) {
        String ip = "([1-9]|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])(\\.(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])){3}";
        Pattern pattern = Pattern.compile(ip);
        Matcher matcher = pattern.matcher(ipAddress);
        return matcher.matches();
    }

    /**
     * 在服务启动时，将 ip2region 加载到内存中
     */
    @PostConstruct
    private static void initIp2Region() {
        try {
            InputStream inputStream = new ClassPathResource("/ipdb/ip2region.xdb").getInputStream();
            byte[] bytes = FileCopyUtils.copyToByteArray(inputStream);
            searcher = Searcher.newWithBuffer(bytes);
        } catch (Exception exception) {
            exception.printStackTrace();
        }
    }

    /**
     * 获取 ip 所属地址
     *
     * @param ip ip
     * @return
     */
    public static String getIpRegion(String ip) {

        boolean isIp = checkIp(ip);

        if (isIp) {

            initIp2Region();

            try {
                // searchIpInfo 的数据格式：国家|区域|省份|城市|ISP
                String searchIpInfo = searcher.search(ip);

                String[] splitIpInfo = searchIpInfo.split("\\|");

                if (splitIpInfo.length > 0) {
                    if ("中国".equals(splitIpInfo[0])) {
                        // 国内属地返回省份
                        return splitIpInfo[2];
                    } else if ("0".equals(splitIpInfo[0])) {
                        if ("内网IP".equals(splitIpInfo[4])) {
                            // 内网 IP
                            return splitIpInfo[4];
                        } else {
                            return "";
                        }
                    } else {
                        // 国外属地返回国家
                        return splitIpInfo[0];
                    }
                }

            } catch (Exception e) {
                e.printStackTrace();
            }
            return "";
        } else {
            throw new IllegalArgumentException("非法的IP地址");
        }

    }

}

对于initIp2Region方法，大家可以自定义改造处理下以满足各自的项目场景，也就是不一定要放到resource目录下。

测试

@SpringBootTest
public class IpUtilTest {

    private static final Logger LOGGER = LoggerFactory.getLogger(IpUtilTest.class);

    /**
     * 测试 ip 所属地址
     */
    @Test
    public void testGetIpRegion() {
        String ip = "220.248.12.158"; // IpRegion:上海
//        String ip = "47.52.236.180"; // IpRegion:香港
//        String ip = "172.22.12.123"; // IpRegion:内网IP
//        String ip = "164.114.53.60"; // IpRegion:美国
        String ipRegion = IpUtil.getIpRegion(ip);
        LOGGER.info("IpRegion:{}", ipRegion);
    }
}

以上为全部内容。