JavaFX BarChart如何居中对齐条？

BarChart<String, Number> barChart = new BarChart<>(new CategoryAxis(), new NumberAxis());

XYChart.Series<String, Number> series = new XYChart.Series<>();
series.getData().add(new XYChart.Data<>("数据1", 10));
series.getData().add(new XYChart.Data<>("数据2", 20));
series.getData().add(new XYChart.Data<>("数据3", 30));

barChart.getData().add(series);

barChart.setBarGap(10);
barChart.setCategoryGap(20);

StackPane root = new StackPane(barChart);

Scene scene = new Scene(root, 400, 300);

StackPane.setAlignment(barChart, Pos.CENTER);

stage.setScene(scene);
stage.show();