根據Request獲取客戶端IP

轉自：

http://www.cnblogs.com/icerainsoft/p/3584532.html

http://www.cnblogs.com/bingya/articles/3134227.html

 

在JSP里，獲取客戶端的IP地址的方法是：request.getRemoteAddr() ，這種方法在大部分情況下都是有效的。但是在通過了Apache,Squid等反向代理軟件就不能獲取到客戶端的真實IP地址了。
如 果使用了反向代理軟件，將http://192.168.1.110:2046/ 的URL反向代理為http://www.xxx.com/ 的URL時，用request.getRemoteAddr() 方法獲取的IP地址是：127.0.0.1　或　192.168.1.110 ，而並不是客戶端的真實ＩＰ。
經過代理以后，由於在客戶端和服務之間增加了中間層，因此服務器無法直接拿到客戶端的IP，服務器端應用也無法直接 通過轉發請求的地址返回給客戶端。但是在轉發請求的HTTP頭信息中，增加了X－FORWARDED－FOR信息。用以跟蹤原有的客戶端IP地址和原來客 戶端請求的服務器地址。當我們訪問http://www.xxx.com/index.jsp/ 時，其實並不是我們瀏覽器真正訪問到了服務器上的index.jsp文件，而是先由代理服務器去訪問http://192.168.1.110:2046 /index.jsp ，代理服務器再將訪問到的結果返回給我們的瀏覽器，因為是代理服務器去訪問index.jsp的，所以index.jsp中通過 request.getRemoteAddr() 的方法獲取的IP實際上是代理服務器的地址，並不是客戶端的IP地址。
於是可得出獲得客戶端真實IP地址的方法一：

public String getRemortIP(HttpServletRequest request) {
  if (request.getHeader("x-forwarded-for") == null) {
   return request.getRemoteAddr();
  }
  return request.getHeader("x-forwarded-for");
}

可是當我訪問http://www.xxx.com/index.jsp/ 時，返回的IP地址始終是unknown，也並不是如上所示的127.0.0.1　或　192.168.1.110 了，而我訪問http://192.168.1.110:2046/index.jsp 時，則能返回客戶端的真實IP地址，寫了個方法去驗證。原因出在了Squid上。squid.conf 的配制文件　forwarded_for 項默認是為on，如果 forwarded_for 設成了 off 　則：X-Forwarded-For: unknown
於是可得出獲得客戶端真實IP地址的方法二：

public String getRemoteHost(javax.servlet.http.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.getRemoteAddr();
    }
    return ip.equals("0:0:0:0:0:0:0:1")?"127.0.0.1":ip;
}

 

如果是Netty4.x

public String getRemoteIP(FullHttpRequest httpRequest) {
        String ip = "";
        try{
            String ipForwarded = httpRequest.headers().get("x-forwarded-for");
            if (StringUtils.isBlank(ipForwarded) || "unknown".equalsIgnoreCase(ipForwarded)) {
                InetSocketAddress insocket = (InetSocketAddress)channel.remoteAddress();
                ip = insocket.getAddress().getHostAddress();
            } else {
                ip = ipForwarded;
            }
        }catch(Exception e){
            logger.error("getRemoteIP(): get remote ip fail!", e);
        }
        if("0:0:0:0:0:0:0:1".equals(ip)){
            ip = "127.0.0.1";
        }
        return ip;
    }

 如果通過了多級反向代理的話，X-Forwarded-For的值並不止一個，而是一串IP值，究竟哪個才是真正的用戶端的真實IP呢？
 答案是取X-Forwarded-For中第一個非unknown的有效IP字符串。如：
    X-Forwarded-For：192.168.1.110, 192.168.1.120, 192.168.1.130, 192.168.1.100
    用戶真實IP為： 192.168.1.110

 

 

package com.ctrip.cep.mockserver.util;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.http.HttpServletRequest;
import java.io.IOException;

/**
 * Created by lzyan on 2017/7/11.
 */
public final class NetworkUtil {
    private static Logger logger = LoggerFactory.getLogger(NetworkUtil.class);

    /**
     * 獲取請求主機IP地址,如果通過代理進來，則透過防火牆獲取真實IP地址
     *
     * @param request
     * @return
     * @throws IOException
     */
    public final static String getIpAddress(HttpServletRequest request) {
        // 獲取請求主機IP地址,如果通過代理進來，則透過防火牆獲取真實IP地址

        String ip = request.getHeader("X-Forwarded-For");
//        logger.debug("getIpAddress(HttpServletRequest) - X-Forwarded-For - String ip=" + ip);

        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("Proxy-Client-IP");
//                logger.debug("getIpAddress(HttpServletRequest) - Proxy-Client-IP - String ip=" + ip);
            }
            if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("WL-Proxy-Client-IP");
//                logger.debug("getIpAddress(HttpServletRequest) - WL-Proxy-Client-IP - String ip=" + ip);
            }
            if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("HTTP_CLIENT_IP");
//                logger.debug("getIpAddress(HttpServletRequest) - HTTP_CLIENT_IP - String ip=" + ip);
            }
            if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("HTTP_X_FORWARDED_FOR");
//                logger.debug("getIpAddress(HttpServletRequest) - HTTP_X_FORWARDED_FOR - String ip=" + ip);
            }
            if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getRemoteAddr();
//                logger.debug("getIpAddress(HttpServletRequest) - getRemoteAddr - String ip=" + ip);
            }
        } else if (ip.length() > 15) {
            String[] ips = ip.split(",");
            for (int index = 0; index < ips.length; index++) {
                String strIp = ips[index];
                if (!("unknown".equalsIgnoreCase(strIp))) {
                    ip = strIp;
                    break;
                }
            }
        }
        return ip;
    }

}