java get network request ip

/**
     * Get the current network request ip
     * @param request
     * @return
     */
    public String getIpAddr(HttpServletRequest request) {
        String ipAddress = request.getHeader("x-forwarded-for");
        if (ipAddress == null || ipAddress.length() == 0 ||
         "unknown".equalsIgnoreCase(ipAddress)) {
            ipAddress = request.getHeader("Proxy-Client-IP");
        }
        if (ipAddress == null || ipAddress.length() == 0 ||
         "unknown".equalsIgnoreCase(ipAddress)) {
            ipAddress = request.getHeader("WL-Proxy-Client-IP");
        }
        if (ipAddress == null || ipAddress.length() == 0 ||
         "unknown".equalsIgnoreCase(ipAddress)) {
            ipAddress = request.getRemoteAddr();
            if (ipAddress.equals("127.0.0.1") ||
             ipAddress.equals("0:0:0:0:0:0:0:1")) {
                //According to the network card, get the IP of the local configuration  
                InetAddress inet = null;
                try {
                    inet = InetAddress.getLocalHost();
                } catch (UnknownHostException e) {
                    e.printStackTrace ();
                }
                ipAddress = inet.getHostAddress();
            }
        }
        //For the case of passing through multiple proxies, the first IP is the real IP of the client, and multiple IPs are divided according to ','  
        if (ipAddress != null && ipAddress.length() > 15) {
           //"***.***.***.***".length() = 15  
            String[] ips = ipAddress.split(",");
            if (ips != null && ips.length > 0) {
                ipAddress = StrUtil.strnull(ips[0]);
            }
        }
        return ipAddress;
    }