TreeView -如何将可扩展TreeItems的字体更改为粗体？

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.TreeItem;
import javafx.scene.control.TreeView;
import javafx.scene.text.Font;
import javafx.scene.text.FontWeight;
import javafx.stage.Stage;

public class TreeViewExample extends Application {

    @Override
    public void start(Stage primaryStage) {
        // 创建根节点
        TreeItem<String> rootItem = new TreeItem<>("Root");

        // 创建子节点
        TreeItem<String> item1 = new TreeItem<>("Item 1");
        TreeItem<String> item2 = new TreeItem<>("Item 2");
        TreeItem<String> item3 = new TreeItem<>("Item 3");

        // 将子节点添加到根节点
        rootItem.getChildren().addAll(item1, item2, item3);

        // 创建TreeView并设置根节点
        TreeView<String> treeView = new TreeView<>(rootItem);

        // 设置字体为粗体
        Font boldFont = Font.font(Font.getDefault().getFamily(), FontWeight.BOLD, Font.getDefault().getSize());
        treeView.getSelectionModel().selectedItemProperty().addListener((observable, oldValue, newValue) -> {
            if (newValue != null) {
                newValue.setFont(boldFont);
            }
            if (oldValue != null) {
                oldValue.setFont(Font.getDefault());
            }
        });

        // 创建场景并显示
        Scene scene = new Scene(treeView, 300, 200);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
}