在项目中往往涉及到“获取客户端IP地址”，常见到下面这样子的代码：
package com.utils;import cn.hutool.core.util.StrUtil;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.server.reactive.ServerHttpRequest;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.Map;/*** 获取客户端IP地址*/
@Slf4j
public class ReactiveAddrUtil {private final static String UNKNOWN_STR = "unknown";/*** 获取客户端IP地址*/public static String getRemoteAddr(ServerHttpRequest request) {Map<String, String> headers = request.getHeaders().toSingleValueMap();String ip = headers.get("X-Forwarded-For");if (isEmptyIP(ip)) {ip = headers.get("Proxy-Client-IP");if (isEmptyIP(ip)) {ip = headers.get("WL-Proxy-Client-IP");if (isEmptyIP(ip)) {ip = headers.get("HTTP_CLIENT_IP");if (isEmptyIP(ip)) {ip = headers.get("HTTP_X_FORWARDED_FOR");if (isEmptyIP(ip)) {ip = request.getRemoteAddress().getAddress().getHostAddress();if ("127.0.0.1".equals(ip) || "0:0:0:0:0:0:0:1".equals(ip)) {// 根据网卡取本机配置的IPip = getLocalAddr();}}}}}} else if (ip.length() > 15) {String[] ips = ip.split(",");for (int index = 0; index < ips.length; index++) {String strIp = ips[index];if (!isEmptyIP(ip)) {ip = strIp;break;}}}return ip;}private static boolean isEmptyIP(String ip) {if (StrUtil.isEmpty(ip) || UNKNOWN_STR.equalsIgnoreCase(ip)) {return true;}return false;}/*** 获取本机的IP地址*/public static String getLocalAddr() {try {return InetAddress.getLocalHost().getHostAddress();} catch (UnknownHostException e) {log.error("InetAddress.getLocalHost()-error", e);}return "";}
}
X-Forwarded-For、Proxy-Client-IP、WL-Proxy-Client-IP
Java 实战系列·获取请求 IP 地址
https://cloud.tencent.com/developer/article/2182781
①X-Forwarded-For：X-Forwarded-For 是一个 HTTP 扩展头部。HTTP/1.1（RFC 2616）协议并没有对它的定义，它最开始是由 Squid 这个缓存代理软件引入，用来表示 HTTP 请求端真实 IP。如今它已经成为事实上的标准，被各大 HTTP 代理、负载均衡等转发服务广泛使用，并被写入 RFC 7239（Forwarded HTTP Extension）标准之中。
②Proxy-Client-IP：一般是经过 apache http 服务器的请求才会有，用 apache http 做代理时一般会加上 Proxy-Client-IP 请求头。
③WL-Proxy-Client-IP：WL-Proxy-Client-IP 是它的 weblogic 插件加上的请求头。
④HTTP_CLIENT_IP： 是代理服务器发送的HTTP头。
⑤HTTP_X_FORWARDED_FOR：Nginx通过http_x_forwarded_for限制来访IP。
⑥获取本机的IP地址 -> InetAddress.getLocalHost().getHostAddress();
