我认为你需要FX UI线程 Platform.runLater（...）为此，你可以使用 时间轴 ，

I think you need FX UI Thread Platform.runLater(...) for that, but you can do something like this using Timeline in you controller class,

@FXML
public void initialize() {

    Timeline clock = new Timeline(new KeyFrame(Duration.ZERO, e -> {        
        second = LocalDateTime.now().getSecond();
        minute = LocalDateTime.now().getMinute();
        hour = LocalDateTime.now().getHour();
        time.setText(hour + ":" + (minute) + ":" + second);
    }),
         new KeyFrame(Duration.seconds(1))
    );
    clock.setCycleCount(Animation.INDEFINITE);
    clock.play();
}