Java FXML in Code eingliedern (über den Controller)

package game;

import javafx.event.Event;
import javafx.fxml.FXML;
import javafx.scene.canvas.Canvas;
import javafx.scene.control.Button;

/**
 * GameController fur die Scene(FXML) von Game
 */
public class GameController {

    @FXML
    Button Exit;

    @FXML
    Button Menu;

    @FXML
    Button Inventory;

    @FXML
    Button Crafting;

    @FXML
    Button placeholderOne;

    @FXML
    Button placeholderTwo;

    @FXML
    public Canvas canvasGame;

    @FXML
    public Canvas canvasInventory;

    @FXML
    protected void buttonPressedExit(Event e) throws Exception {        //Sobald Exit gedruckt wird --> Alles schliesst sich
        System.exit(0);                                                 //Alles schliesst sich in 0
    }

    @FXML
    protected void buttonPressedMenu(Event e) throws Exception {

    }

    @FXML
    protected void buttonPressedInventory(Event e) throws Exception {

    }

    @FXML
    protected void buttonPressedCrafting(Event e) throws Exception {

    }

    @FXML
    protected void buttonPressedplaceholderOne(Event e) throws Exception {

    }

    @FXML
    protected void buttonPressedplaceholderTwo(Event e) throws Exception {

    }


}

GameController gameController = new GameController;
Canvas canvas = gameController.canvasGame;