获取IP地址

/***
     * 获取ip地址
     * @param request
     * @return
     */
    public static String getIpAddr(HttpServletRequest request) {
        Object o=request.getParameter("_remote_ip");
        logger.debug("getIpAddr _remote_ip:"+ o);
        if(null!=o && !"".equals(o.toString())){
            return o.toString();
        }
        long start=System.currentTimeMillis();
        String ip = request.getHeader("x-forwarded-for");
        if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {      
            ip = request.getHeader("X-Real-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("REMOTE-HOST");
        }
        if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getRemoteAddr();
        }
        logger.debug("time :"+ (System.currentTimeMillis()-start) +" getIpAddr:"+ip);
        return ip;
    }