java实用工具类——java后端通过request对象获取请求的ip地址

/**
* 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;
*
* @param request
* @return
* @throws IOException
*/
public final static String getIpAddress(HttpServletRequest request) throws IOException {
   
    String ip = request.getHeader("X-Forwarded-For");
    if (LOGGER.isInfoEnabled()) {
        LOGGER.info("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");
            if (LOGGER.isInfoEnabled()) {
                LOGGER.info("getIpAddress(HttpServletRequest) - Proxy-Client-IP - String ip=" + ip);
            }
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("WL-Proxy-Client-IP");
            if (LOGGER.isInfoEnabled()) {
                LOGGER.info("getIpAddress(HttpServletRequest) - WL-Proxy-Client-IP - String ip=" + ip);
            }
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("HTTP_CLIENT_IP");
            if (LOGGER.isInfoEnabled()) {
                LOGGER.info("getIpAddress(HttpServletRequest) - HTTP_CLIENT_IP - String ip=" + ip);
            }
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("HTTP_X_FORWARDED_FOR");
            if (LOGGER.isInfoEnabled()) {
                LOGGER.info("getIpAddress(HttpServletRequest) - HTTP_X_FORWARDED_FOR - String ip=" + ip);
            }
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getRemoteAddr();
            if (LOGGER.isInfoEnabled()) {
                LOGGER.info("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 = (String) ips[index];
            if (!("unknown".equalsIgnoreCase(strIp))) {
                ip = strIp;
                break;
            }
        }
    }
    return ip;
}