Use Java implementation to obtain client IP address

import ;
import ;

import ;
import ;
import ;

/**
  * Get IP address tool class
  */
public final class IpUtil {

    private static final String UNKNOWN = "unknown";
    private static final String IPV6_LOCAL = "::1";  // Recommended compression
    private IpUtil(){
        throw new AssertionError();
    }

    /**
      * Get the IP address of the requesting user
      * @return
      */
    public static String getRequestIp() {
        ServletRequestAttributes attributes = (ServletRequestAttributes) ();
        HttpServletRequest request = ();
        return getRequestIp(request);
    }

    /**
      * Get the IP address of the requesting user
      * @param request
      * @return
      */
    public static String getRequestIp(HttpServletRequest request) {
        String ip = ("x-forwarded-for");

        // Process multi-level proxy to obtain the first non-unknown valid IP        if (ip != null && !() && !(ip)) {
            ip = (",")[0].trim();  // Get the first IP        } else {
            ip = ("X-Real-IP");  // Commonly used in Nginx proxy        }

        // Alternative solution: Try to get from other headers        if (ip == null || () || (ip)) {
            ip = ("Proxy-Client-IP");
        }
        if (ip == null || () || (ip)) {
            ip = ("WL-Proxy-Client-IP");
        }
        if (ip == null || () || (ip)) {
            ip = ();  // Get the remote address by default        }

        // If it is a local loopback address, it returns the IP of the local machine        if (IPV6_LOCAL.equals(ip) || "127.0.0.1".equals(ip)) {
            ip = getLocalhostIp();  // Get local IP        }

        return ip;
    }

    private static String getLocalhostIp() {
        try {
            InetAddress inetAddress = ();
            return ();
        } catch (UnknownHostException e) {
            ();
            return "127.0.0.1";  // If it cannot be retrieved, return the loopback address        }
    }

}

server {
    listen 80;
    server_name ;

    location / {
        # Forward the real IP of the client        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $host;

        # Proxy forwards requests to gateway service        proxy_pass http://localhost:1000/;
    }
}