java使用HttpServletRequest獲取請求真實ip地址

public static 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();
            String localIp = "127.0.0.1";
            String localIpv6 = "0:0:0:0:0:0:0:1";
            if (ipAddress.equals(localIp) || ipAddress.equals(localIpv6)) {
                // 根據網卡取本機配置的IP
                InetAddress inet = null;
                try {
                    inet = InetAddress.getLocalHost();
                    ipAddress = inet.getHostAddress();
                } catch (UnknownHostException e) {
                    e.printStackTrace();
                }
            }
        }
        // 對於通過多個代理的情況，第一個IP為客戶端真實IP,多個IP按照','分割
        String ipSeparate = ",";
        int ipLength = 15;
        if (ipAddress != null && ipAddress.length() > ipLength) {
            if (ipAddress.indexOf(ipSeparate) > 0) {
                ipAddress = ipAddress.substring(0, ipAddress.indexOf(ipSeparate));
            }
        }
        return ipAddress;
    }