Java 获取真实请求IP

在使用Nginx或Apache等代理的情况下，需要Nginx或Apache代替客户端去访问服务器。当请求包经过反向代理后，在代理服务器这里这个IP数据包的IP包头做了修改，最终后端WEB服务器得到的数据包的头部源IP地址是代理服务器的IP地址。这样一来，后端服务器的程序就无法获取用户的真实ip。

nginx中配置

proxy_set_header Host  $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Real-Port $remote_port;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
                    

Apache有代理的情况：

vi /usr/local/apache/conf/httpd.conf
Include conf/extra/httpd-remoteip.conf
vi /usr/local/apache/conf/extra/httpd-remoteip.conf
LoadModule remoteip_module modules/mod_remoteip.so 
RemoteIPHeader X-Forwarded-For 
RemoteIPinternalProxy 127.0.0.1 

X-Real-IP 真实请求IP【Nginx中设置】

X-Forwarded-For IP链，真实IP + , + 代理IP1.... + , + 代理IPN

request.getRemoteAddr() 获取真实IP/代理IP（用户使用代理软件时无法获取真实IP）

1. 真实请求IP

import javax.servlet.http.HttpServletRequest;
import java.net.InetAddress;
import java.net.UnknownHostException;

public class IPUtil {

    /**
     * 真是请求IP
     *
     * @param request
     * @return
     */
    public static String getRealRequestIp(HttpServletRequest request) {
        String ip = request.getHeader("x-forwarded-for");
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("WL-Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("HTTP_CLIENT_IP");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("HTTP_X_FORWARDED_FOR");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getRemoteAddr();
        }
        if (null != ip && ip.contains(",")) {
            ip = ip.substring(0, ip.indexOf(","));
        }
        return ip;
    }
    
}

2.本机IP

​​​​​​​import javax.servlet.http.HttpServletRequest;
import java.net.InetAddress;
import java.net.UnknownHostException;

public class IPUtil {
    /**
     * 本机IP
     *
     * @return
     * @throws UnknownHostException
     */
    public static String getLocalIp() throws UnknownHostException {
        return InetAddress.getLocalHost().getHostAddress();
    }

}