Java获取客户端IP地址示例

首先是获取 IP，直接上代码

import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;import javax.servlet.http.HttpServletRequest;
import java.net.InetAddress;
import java.net.UnknownHostException;/*** 获取IP地址工具类*/
public final class IpUtil {private static final String UNKNOWN = "unknown";private static final String IPV6_LOCAL = "::1";  // 推荐用压缩形式private IpUtil(){throw new AssertionError();}/*** 获取请求用户的IP地址* @return*/public static String getRequestIp() {ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();HttpServletRequest request = attributes.getRequest();return getRequestIp(request);}/*** 获取请求用户的IP地址* @param request* @return*/public static String getRequestIp(HttpServletRequest request) {String ip = request.getHeader("x-forwarded-for");// 处理多级代理，获取第一个非 unknown 的有效 IPif (ip != null && !ip.isEmpty() && !UNKNOWN.equalsIgnoreCase(ip)) {ip = ip.split(",")[0].trim();  // 取第一个 IP} else {ip = request.getHeader("X-Real-IP");  // 常见于 Nginx 代理}// 备用方案：尝试从其他头部获取if (ip == null || ip.isEmpty() || UNKNOWN.equalsIgnoreCase(ip)) {ip = request.getHeader("Proxy-Client-IP");}if (ip == null || ip.isEmpty() || UNKNOWN.equalsIgnoreCase(ip)) {ip = request.getHeader("WL-Proxy-Client-IP");}if (ip == null || ip.isEmpty() || UNKNOWN.equalsIgnoreCase(ip)) {ip = request.getRemoteAddr();  // 默认获取远程地址}// 如果是本地回环地址，则返回本地机器的 IPif (IPV6_LOCAL.equals(ip) || "127.0.0.1".equals(ip)) {ip = getLocalhostIp();  // 获取本地 IP}return ip;}private static String getLocalhostIp() {try {InetAddress inetAddress = InetAddress.getLocalHost();return inetAddress.getHostAddress();} catch (UnknownHostException e) {e.printStackTrace();return "127.0.0.1";  // 如果无法获取，则返回回环地址}}}

但是今天发现一个问题，所有的地址都显示为 127.0.0.1，我一琢磨应该是 nginx 代理导致的，所以给 nginx 加上下面的配置

server {listen 80;server_name your-domain.com;location / {# 转发客户端的真实 IPproxy_set_header X-Real-IP $remote_addr;proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;proxy_set_header Host $host;# 代理转发请求到网关服务proxy_pass http://localhost:1000/;}
}

重启 nginx 后再次请求就拿到了真实的 IP 地址了（注意所谓的真实 IP 不一定真实，这个东西是可以伪造的，至于防范措施大家自己去搜，道高一尺魔高一丈）