应用程序启动方法异常，无法修复

Question

我尝试的一切都不起作用。当我从 fxml 文件中删除控制器类时，除了屏幕不工作外，一切正常。这是我的文件： 请告诉我是否需要提供更多。

package main.userInterfaceLaag;

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;
import main.domeinLaag.*;
import java.time.LocalDate;

public class Main extends Application {
    public static void main(String[] args){
        Docent docent1 = new Docent("Willem Pietersen", "[email protected]", "12345", 
        LocalDate.now().minusYears(30), "wpieter", Bevoegdheid.Docent, 12345);
        Docent docent2 = new Docent("Jan Willems", "[email protected]", "12345", 
        LocalDate.now().minusYears(35), "jwillems", Bevoegdheid.Docent, 56789);

        docent1.voegDocentToe(docent2);
        docent2.voegDocentToe(docent1);
        System.out.println(docent1.geefAlleDocenten());
        System.out.println(docent1.geefNaam());

        Klas klas1 = new Klas("V1A");

        Vak vak1 = new Vak(12345, "OOAD");
        Vak vak2 = new Vak(54325, "OOP");

        Lokaal lokaal1 = new Lokaal("1.035");
        Lokaal lokaal2 = new Lokaal("5.993");

        launch(args);
    }

    @Override
    public void start(Stage stage) throws Exception {
        String fxmlPagina = "LesInvoeren.fxml";
        FXMLLoader loader = new FXMLLoader(getClass().getResource(fxmlPagina));
        Parent root = loader.load();

        stage.setTitle("HotelApp");
        stage.setScene(new Scene(root));
        stage.show();
}

}//缺席

我的控制器类：

<AnchorPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="- 
Infinity" prefHeight="449.0" prefWidth="618.0"
xmlns="http://javafx.com/javafx/19" xmlns:fx="http://javafx.com/fxml/1" 
fx:controller="main.userInterfaceLaag.LesInvoeren">

    "C:\Program Files\Java\jdk-19\bin\java.exe" --module-path lib --add-modules javafx.controls,javafx.fxml "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2022.3.2\lib\idea_rt.jar=57857:C:\Program Files\JetBrains\IntelliJ IDEA 2022.3.2\bin" -Dfile.encoding=UTF-8 -Dsun.stdout.encoding=UTF-8 -Dsun.stderr.encoding=UTF-8 -classpath C:\Users\prody\IdeaProjects\Team-skunk-V1A\out\production\Team-skunk-V1A;C:\Users\prody\.m2\repository\org\openjfx\javafx-fxml\19\javafx-fxml-19.jar;C:\Users\prody\.m2\repository\org\openjfx\javafx-fxml\19\javafx-fxml-19-win.jar;C:\Users\prody\.m2\repository\org\openjfx\javafx-controls\19\javafx-controls-19.jar;C:\Users\prody\.m2\repository\org\openjfx\javafx-controls\19\javafx-controls-19-win.jar;C:\Users\prody\.m2\repository\org\openjfx\javafx-graphics\19\javafx-graphics-19.jar;C:\Users\prody\.m2\repository\org\openjfx\javafx-graphics\19\javafx-graphics-19-win.jar;C:\Users\prody\.m2\repository\org\openjfx\javafx-base\19\javafx-base-19.jar;C:\Users\prody\.m2\repository\org\openjfx\javafx-base\19\javafx-base-19-win.jar main.userInterfaceLaag.Main
[main.domeinLaag.Docent@6adede5]
Willem Pietersen
Exception in Application start method
java.lang.reflect.InvocationTargetException
    at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:119)
    at java.base/java.lang.reflect.Method.invoke(Method.java:578)
    at javafx.graphics@19/com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:465)
    at javafx.graphics@19/com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:364)
    at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
    at java.base/java.lang.reflect.Method.invoke(Method.java:578)
    at java.base/sun.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:1081)
Caused by: java.lang.RuntimeException: Exception in Application start method
    at javafx.graphics@19/com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:901)
    at javafx.graphics@19/com.sun.javafx.application.LauncherImpl.lambda$launchApplication$2(LauncherImpl.java:196)
    at java.base/java.lang.Thread.run(Thread.java:1589)
Caused by: javafx.fxml.LoadException: 
/C:/Users/prody/IdeaProjects/Team-skunk-V1A/out/production/Team-skunk-V1A/main/userInterfaceLaag/LesInvoeren.fxml

    at javafx.fxml@19/javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2707)
    at javafx.fxml@19/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2677)
    at javafx.fxml@19/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2548)
    at javafx.fxml@19/javafx.fxml.FXMLLoader.load(FXMLLoader.java:2516)
    at main.userInterfaceLaag.Main.start(Main.java:37)
    at javafx.graphics@19/com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$9(LauncherImpl.java:847)
    at javafx.graphics@19/com.sun.javafx.application.PlatformImpl.lambda$runAndWait$12(PlatformImpl.java:484)
    at javafx.graphics@19/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:457)
    at java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
    at javafx.graphics@19/com.sun.javafx.application.PlatformImpl.lambda$runLater$11(PlatformImpl.java:456)
    at javafx.graphics@19/com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:96)
    at javafx.graphics@19/com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at javafx.graphics@19/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:184)
    ... 1 more
Caused by: java.lang.reflect.InvocationTargetException
    at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:116)
    at java.base/java.lang.reflect.Method.invoke(Method.java:578)
    at com.sun.javafx.reflect.Trampoline.invoke(MethodUtil.java:77)
    at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
    at java.base/java.lang.reflect.Method.invoke(Method.java:578)
    at javafx.base@19/com.sun.javafx.reflect.MethodUtil.invoke(MethodUtil.java:275)
    at javafx.fxml@19/com.sun.javafx.fxml.MethodHelper.invoke(MethodHelper.java:84)
    at javafx.fxml@19/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2673)
    ... 12 more
Caused by: java.lang.NullPointerException: Cannot invoke "main.domeinLaag.Docent.geefAlleDocenten()" because "this.docent" is null
    at main.userInterfaceLaag.LesInvoeren.initialize(LesInvoeren.java:24)
    at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
    ... 19 more
Exception running application main.userInterfaceLaag.Main

Process finished with exit code 1

enter code here

    package main.userInterfaceLaag;

import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.fxml.FXML;
import javafx.scene.control.ComboBox;
import main.domeinLaag.*;

import java.util.ArrayList;

public class LesInvoeren {
    private Docent docent;
    private Vak vak;
    private Klas klas;
    private Lokaal lokaal;
    @FXML private ComboBox docentComboBox;
    @FXML private ComboBox vakComboBox;
    @FXML private ComboBox klasComboBox;
    @FXML private ComboBox lokaalComboBox;

    public void initialize() {
        ObservableList<String> alleNamen = FXCollections.observableArrayList();

        for (Docent d: docent.geefAlleDocenten()) {
            System.out.println(d.geefNaam());
            alleNamen.add(d.geefNaam());
        }

        docentComboBox.setItems(alleNamen);
//        docentComboBox.setItems(FXCollections.observableArrayList(alleNamen));
        vakComboBox.setItems(FXCollections.observableArrayList(vak.geefAlleVakken()));
        klasComboBox.setItems(FXCollections.observableArrayList(klas.geefAlleKlassen()));
        lokaalComboBox.setItems(FXCollections.observableArrayList(lokaal.geefAlleLokalen()));
    }




}

堆栈跟踪：

我的地图：