在javafx中更改场景

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;

public class MainApp extends Application {

    private Stage primaryStage;

    @Override
    public void start(Stage primaryStage) {
        this.primaryStage = primaryStage;
        showScene1(); // 初始显示场景1
    }

    public void showScene1() {
        try {
            FXMLLoader loader = new FXMLLoader(getClass().getResource("scene1.fxml"));
            Parent root = loader.load();
            Scene scene = new Scene(root);
            primaryStage.setScene(scene);
            primaryStage.show();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void showScene2() {
        try {
            FXMLLoader loader = new FXMLLoader(getClass().getResource("scene2.fxml"));
            Parent root = loader.load();
            Scene scene = new Scene(root);
            primaryStage.setScene(scene);
            primaryStage.show();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

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