Java 如何解决这个问题；“应用程序启动方法”中的异常；？

我是JavaFX新手，我曾尝试使用Netbeans IDE创建JavaFX FXML应用程序项目，但我遇到了这个例外

这是我的java类：

    public class JavaFXApplication9 extends Application {

        @Override
        public void start(Stage stage) throws Exception {
            Parent root = FXMLLoader.load(getClass().getResource("FXMLDocument.fxml"));

            Scene scene = new Scene(root);

            stage.setScene(scene);
            stage.show();
        }

        /**
         * @param args the command line arguments
         */
        public static void main(String[] args) {
            launch(args);
        }

    }

这是我的FXML代码：

    <?xml version="1.0" encoding="UTF-8"?>

    <?import javafx.scene.control.Button?>
    <?import javafx.scene.layout.AnchorPane?>

    <AnchorPane id="AnchorPane" prefHeight="200" prefWidth="320" xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/8.0.171" fx:controller="javafxapplication9.FXMLDocumentController">
        <children>
            <Button fx:id="button" layoutX="126" layoutY="90" onAction="#handleButtonAction" text="Click Me!" />
        </children>
    </AnchorPane>

这是应用程序启动方法

java.lang.reflect.InvocationTargetException

javafx中的异常

java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:389)
    at com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:328)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at sun.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:767)
    Caused by: java.lang.RuntimeException: Exception in Application start method
    at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$155(LauncherImpl.java:182)
    at java.lang.Thread.run(Thread.java:745)
    Caused by: java.lang.NullPointerException: Location is required.
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3207)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3175)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3148)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3124)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3104)
    at javafx.fxml.FXMLLoader.load(FXMLLoader.java:3097)
    at javafxapplication9.JavaFXApplication9.start(JavaFXApplication9.java:22)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$162(LauncherImpl.java:863)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$175(PlatformImpl.java:326)
    at com.sun.javafx.application.PlatformImpl.lambda$null$173(PlatformImpl.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$174(PlatformImpl.java:294)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
    ... 1 more
    Exception running application javafxapplication9.JavaFXApplication9
    E:\Netbeans Project\JavaFXApplication9\nbproject\build-impl.xml:1052: The following error occurred 
    while executing this line:
    E:\Netbeans Project\JavaFXApplication9\nbproject\build-impl.xml:806: Java returned: 1
    BUILD FAILED (total time: 1 second)

---

此异常的主要原因是NullPointerException（请参阅stacktrace:

位置是必需的

）。所以你试着使用一些没有启动的东西。

---

如果没有任何代码片段，很难找到错误。

您发布的代码对我很有用。类

FXMLDocumentController

是否在包

javafxapplication9

中？文件

FXMLDocument.fxml

是否与文件

JavaFXApplication9.class

位于同一目录中？注意，我询问的是编译的类，而不是源代码文件。如果项目结构正常，您可能还需要检查堆栈跟踪以显示此位置：父根=FXMLLoader.load（getClass（）.getResource（“FXMLDocument.fxml”）；堆栈跟踪显示此位置：父根=FXMLLoader.load（getClass（）.getResource（“FXMLDocument.fxml”）@MirwaisFaizi确保您的FXMLDocument.fxml与JavaFXApplication9类位于同一文件夹中。无论出于何种目的，getClass（）方法都会获取调用它的类的位置，然后getResource（）方法会找到与其相关的资源。因此getClass（）.getResource（“FXMLDocument.fxml”）指向同一文件夹中的文件。我的Java类、控制器类和fxml类位于同一文件夹中。

java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:389)
    at com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:328)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at sun.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:767)
    Caused by: java.lang.RuntimeException: Exception in Application start method
    at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$155(LauncherImpl.java:182)
    at java.lang.Thread.run(Thread.java:745)
    Caused by: java.lang.NullPointerException: Location is required.
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3207)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3175)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3148)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3124)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3104)
    at javafx.fxml.FXMLLoader.load(FXMLLoader.java:3097)
    at javafxapplication9.JavaFXApplication9.start(JavaFXApplication9.java:22)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$162(LauncherImpl.java:863)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$175(PlatformImpl.java:326)
    at com.sun.javafx.application.PlatformImpl.lambda$null$173(PlatformImpl.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$174(PlatformImpl.java:294)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
    ... 1 more
    Exception running application javafxapplication9.JavaFXApplication9
    E:\Netbeans Project\JavaFXApplication9\nbproject\build-impl.xml:1052: The following error occurred 
    while executing this line:
    E:\Netbeans Project\JavaFXApplication9\nbproject\build-impl.xml:806: Java returned: 1
    BUILD FAILED (total time: 1 second)