Javafx如何正确切换场景？

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class SceneSwitchExample extends Application {
    private Stage primaryStage;

    @Override
    public void start(Stage primaryStage) throws Exception {
        this.primaryStage = primaryStage;
        
        // 加载初始场景
        Parent root = FXMLLoader.load(getClass().getResource("initial_scene.fxml"));
        Scene initialScene = new Scene(root);
        
        // 设置初始场景
        primaryStage.setScene(initialScene);
        primaryStage.show();
    }

    // 切换到目标场景
    private void switchToScene(String sceneName) throws Exception {
        // 加载目标场景
        Parent root = FXMLLoader.load(getClass().getResource(sceneName + ".fxml"));
        Scene targetScene = new Scene(root);
        
        // 切换场景
        primaryStage.setScene(targetScene);
        primaryStage.show();
    }

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