1、引进的必要性log4j-1.2.14.jar

package org.ydd.test;

import java.util.Enumeration;

import javax.servlet.http.HttpServletRequest;

import org.apache.log4j.Logger;

/**

 * @author coco

 * @version

 * 获取IP4

 */

public class IP4 {

	private static final Logger log = Logger.getLogger(IP4.class);

	/**

	 * 获取client真实IP地址（注意：假设通过Squid反向代理软件。需更改squid.conf配置文件forwarded_for项默认是为on。

	 * 否则获取到的IP为unknown）

	 * @param request

	 * @return

	 */

	@SuppressWarnings({ "rawtypes", "unchecked" })

	public  static String getIpAddr(HttpServletRequest request) {

	log.debug("====================================================");

	if(log.isDebugEnabled()){

	StringBuffer buf = new StringBuffer("all head info:\n");

	Enumeration enumeration = request.getHeaderNames();

	while(enumeration.hasMoreElements()){

	Object head = enumeration.nextElement();

	if(null != head){

	String value = request.getHeader(String.valueOf(head));

	buf.append(head + "=" + value + "\n");

	}

	}

	log.debug(buf.toString());

	}

	String ip = request.getHeader("x-forwarded-for");

	log.debug("request.getHeader(\"x-forwarded-for\")=" + ip);

	if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {

	ip = request.getHeader("X-Forwarded-For");

	log.debug("request.getHeader(\"X-Forwarded-For\")=" + ip);

	}

	if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {

	ip = request.getHeader("Proxy-Client-IP");

	log.debug("request.getHeader(\"Proxy-Client-IP\")=" + ip);

	}

	if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {

	ip = request.getHeader("WL-Proxy-Client-IP");

	log.debug("request.getHeader(\"WL-Proxy-Client-IP\")=" + ip);

	}

	if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {

	ip = request.getHeader("HTTP_CLIENT_IP");

	log.debug("request.getHeader(\"HTTP_CLIENT_IP\")=" + ip);

	}

	if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {

	ip = request.getHeader("HTTP_X_FORWARDED_FOR");

	log.debug("request.getHeader(\"HTTP_X_FORWARDED_FOR\")=" + ip);

	}

	if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {

	ip = request.getRemoteAddr();

	log.debug("request.getRemoteAddr()=" + ip);

	}

	if(null != ip && ip.indexOf(',') != -1){

	//假设通过了多级反向代理的话，X-Forwarded-For的值并不止一个，而是一串 IP 值

	//取X-Forwarded-For中第一个非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

	//用户真实IP为： 192.168.1.110

	//注意:当訪问地址为 localhost 时 地址格式为 0:0:0:0:0:0:1

	log.debug("ip=" + ip);

	String[] ips = ip.split(",");

	for (int i = 0; i < ips.length; i++) {

	if(null != ips[i] && !"unknown".equalsIgnoreCase(ips[i])){

	ip = ips[i];

	break;

	}

	}

	if("0:0:0:0:0:0:1".equals(ip)){

	log.warn("因为client訪问地址使用 localhost，获取client真实IP地址错误，请使用IP方式訪问");

	}

	}

	if("unknown".equalsIgnoreCase(ip)){

	log.warn("因为client通过Squid反向代理软件訪问，获取client真实IP地址错误，请更改squid.conf配置文件forwarded_for项默认是为on解决");

	}

	log.debug("====================================================");

	return ip;

	}

}