移动端获取客户端mac时间过久怎么优化，感谢各位大佬

Question

public class GetNowIP {

 public static String getLocalMac(HttpServletRequest request) throws IOException {
    String ip = request.getHeader("X-real-ip");

        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("x-forwarded-for");
        }
        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();
        }
        return getLocalMac(ip);
    }


 public    static String getLocalMac(String ip) throws IOException {
    String macAddr = null;
    Process process = Runtime.getRuntime().exec("nbtstat -a " + ip);
    BufferedReader br = new BufferedReader(new InputStreamReader(process.getInputStream()));
    Pattern pattern = Pattern.compile("([A-F0-9]{2}-){5}[A-F0-9]{2}");
    Matcher matcher;
    for (String strLine = br.readLine(); strLine != null; strLine = br.readLine()) {
        matcher = pattern.matcher(strLine);
        if (matcher.find()) {
            macAddr = matcher.group();
            break;
        }
    }

    System.out.println(macAddr);
    return macAddr;

}

}