public class IPUtil {    private static Logger logger = Logger.getLogger(IPUtil.class);    /**     * 获取请求主机IP地址,如果通过代理进来，则透过防火墙获取真实IP地址;     */    public final static String getIpAddress(HttpServletRequest request) throws IOException {        String ip = request.getHeader("X-Forwarded-For");        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {            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();            }        } else if (ip.length() > 15) {            String[] ips = ip.split(",");            for (int index = 0; index < ips.length; index++) {                String strIp = (String) ips[index];                if (!("unknown".equalsIgnoreCase(strIp))) {                    ip = strIp;                    break;                }            }        }        return ip;    }}