java获取客户端用户真实ip

参考：

https://github.com/lionsoul2014/ip2region

https://www.keppel.fun/articles/2019/06/15/1560590277332.html

https://my.oschina.net/wangmengjun/blog/815697

https://www.jianshu.com/p/95ba828d9a8c

https://blog.csdn.net/yqwang75457/article/details/56489391

原理：使用离线数据地址库查找ip

一、ip2region安装

maven仓库地址：

<dependency>
    <groupId>org.lionsoul</groupId>
    <artifactId>ip2region</artifactId>
    <version>1.7.2</version>
</dependency>

二、编写工具类

package cn.factorybox.common.utils;

import cn.factorybox.common.entity.Constant;
import org.lionsoul.ip2region.DataBlock;
import org.lionsoul.ip2region.DbConfig;
import org.lionsoul.ip2region.DbSearcher;
import org.lionsoul.ip2region.Util;

import javax.servlet.http.HttpServletRequest;
import java.io.File;
import java.lang.reflect.Method;
import java.net.InetAddress;
import java.net.UnknownHostException;

/**
 * Ip工具类，获取ip
 */
public class IpUtils {

    // 获取ip地址
    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="";
        }
        return ipAddress;
    }

    // 根据ip地址获取城市
    public static String getCityInfo(String ip){
        //db
//        String dbPath = IpUtils.class.getResource("/ip2region.db").getPath();
        String dbPath = Constant.DB_PATH;
        File file = new File(dbPath);
        if ( file.exists() == false ) {
            System.out.println("Error: Invalid ip2region.db file");
        }
        //查询算法
        int algorithm = DbSearcher.BTREE_ALGORITHM; //B-tree
        //DbSearcher.BINARY_ALGORITHM //Binary
        //DbSearcher.MEMORY_ALGORITYM //Memory
        try {
            DbConfig config = new DbConfig();
            DbSearcher searcher = new DbSearcher(config, dbPath);
            //define the method
            Method method = null;
            switch ( algorithm )
            {
                case DbSearcher.BTREE_ALGORITHM:
                    method = searcher.getClass().getMethod("btreeSearch", String.class);
                    break;
                case DbSearcher.BINARY_ALGORITHM:
                    method = searcher.getClass().getMethod("binarySearch", String.class);
                    break;
                case DbSearcher.MEMORY_ALGORITYM:
                    method = searcher.getClass().getMethod("memorySearch", String.class);
                    break;
            }
            DataBlock dataBlock = null;
            if ( Util.isIpAddress(ip) == false ) {
                System.out.println("Error: Invalid ip address");
            }
            dataBlock  = (DataBlock) method.invoke(searcher, ip);
            return dataBlock.getRegion();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
}

三、如果使用nginx进行了反向代理需要进行配置

        location /prod-api {
            # 配置此处用于获取客户端的真实IP
            proxy_set_header Host $http_host;
	    proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto $scheme;
            proxy_pass  http://localhost:xxxx/api;
        }