JavaFX：应用程序启动方法中出现异常 java.lang.reflect.InitationTargetException

Question

我真的很绝望。\n我不\xe2\x80\x99不知道为什么，但每次我尝试运行我的程序时都会出现此错误。\n我正在使用 Netbeans 和 Java 10.0.2，以便已经安装了 JavaFX。\ n我认为\xe2\x80\x99s是由于FXML文件的一些问题造成的。\n你能帮助我吗？

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java.lang.reflect.InvocationTargetException\n    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)\n    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)\n    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)\n    at java.base/java.lang.reflect.Method.invoke(Method.java:564)\n    at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:473)\n    at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:372)\n    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)\n    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)\n    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)\n    at java.base/java.lang.reflect.Method.invoke(Method.java:564)\n    at java.base/sun.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:941)\nCaused by: java.lang.RuntimeException: Exception in Application start method\n    at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:973)\n    at javafx.graphics/com.sun.javafx.application.LauncherImpl.lambda$launchApplication$2(LauncherImpl.java:198)\n    at java.base/java.lang.Thread.run(Thread.java:844)\nCaused by: javafx.fxml.LoadException: Root hasn't been set. Use method setRoot() before load.\nfile:/C:/Users/User/Documents/NetBeansProjects/gruppo71/dist/run2124011701/gruppo71.jar!/gruppo71/FXMLDocument.fxml:13\n\n    at javafx.fxml/javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2621)\n    at javafx.fxml/javafx.fxml.FXMLLoader.access$100(FXMLLoader.java:105)\n    at javafx.fxml/javafx.fxml.FXMLLoader$RootElement.constructValue(FXMLLoader.java:1338)\n    at javafx.fxml/javafx.fxml.FXMLLoader$ValueElement.processStartElement(FXMLLoader.java:754)\n    at javafx.fxml/javafx.fxml.FXMLLoader.processStartElement(FXMLLoader.java:2722)\n    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2552)\n    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2466)\n    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3253)\n    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3210)\n    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3179)\n    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3152)\n    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3129)\n    at javafx.fxml/javafx.fxml.FXMLLoader.load(FXMLLoader.java:3122)\n    at gruppo71.Gruppo71.start(Gruppo71.java:21)\n    at javafx.graphics/com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$9(LauncherImpl.java:919)\n    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runAndWait$11(PlatformImpl.java:449)\n    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$9(PlatformImpl.java:418)\n    at java.base/java.security.AccessController.doPrivileged(Native Method)\n    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:417)\n    at javafx.graphics/com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:96)\n    at javafx.graphics/com.sun.glass.ui.win.WinApplication._runLoop(Native Method)\n    at javafx.graphics/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:175)\n    ... 1 more\nException running application gruppo71.Gruppo71\nJava Result: 1\n

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我的主要是这样的：

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\nimport javafx.application.Application;\nimport javafx.fxml.FXMLLoader;\nimport javafx.scene.Parent;\nimport javafx.scene.Scene;\nimport javafx.stage.Stage;\n\n/**\n *\n * @author User\n */\npublic class Gruppo71 extends Application {\n    \n    @Override\n    public void start(Stage stage) throws Exception {\n        Parent root = FXMLLoader.load(getClass().getResource("FXMLDocument.fxml"));\n        \n        Scene scene = new Scene(root);\n        \n        stage.setScene(scene);\n        stage.show();\n    }\n\n    /**\n     * @param args the command line arguments\n     */\n    public static void main(String[] args) {\n        launch(args);\n    }\n} \n

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我的 FXML 代码是：

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\n<?import javafx.scene.control.Button?>\n<?import javafx.scene.control.ContextMenu?>\n<?import javafx.scene.control.DatePicker?>\n<?import javafx.scene.control.MenuItem?>\n<?import javafx.scene.control.SplitPane?>\n<?import javafx.scene.control.TableColumn?>\n<?import javafx.scene.control.TableView?>\n<?import javafx.scene.control.TextField?>\n<?import javafx.scene.layout.AnchorPane?>\n\n<fx:root id="AnchorPane" prefHeight="300.0" prefWidth="450.0" type="AnchorPane" xmlns="http://javafx.com/javafx/10.0.2" xmlns:fx="http://javafx.com/fxml/1" fx:controller="gruppo71.FXMLDocumentController">\n   <children>\n      <SplitPane dividerPositions="0.13087248322147652" layoutX="28.0" orientation="VERTICAL" prefHeight="200.0" prefWidth="320.0" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0">\n        <items>\n          <AnchorPane minHeight="0.0" minWidth="0.0" prefHeight="100.0" prefWidth="160.0">\n               <children>\n                  <Button fx:id="aggiungiButton" layoutX="10.0" layoutY="5.0" mnemonicParsing="false" onAction="#addEvento" text="Aggiungi Evento" AnchorPane.bottomAnchor="5.0" AnchorPane.leftAnchor="10.0" AnchorPane.topAnchor="5.0" />\n                  <DatePicker fx:id="dataPicker" layoutX="114.0" layoutY="6.0" prefHeight="26.0" prefWidth="150.0" AnchorPane.bottomAnchor="5.0" AnchorPane.leftAnchor="124.0" AnchorPane.topAnchor="5.0" />\n                  <TextField fx:id="descriptionField" layoutX="285.0" layoutY="6.0" text="aggiungi descrizione..." AnchorPane.bottomAnchor="5.0" AnchorPane.leftAnchor="284.0" AnchorPane.rightAnchor="10.0" AnchorPane.topAnchor="5.0" />\n               </children>\n            </AnchorPane>\n          <AnchorPane minHeight="0.0" minWidth="0.0" prefHeight="100.0" prefWidth="160.0">\n               <children>\n                  <TableView fx:id="mainTab" layoutX="14.0" prefHeight="256.0" prefWidth="448.0" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0">\n                    <columns>\n                      <TableColumn fx:id="dataColumn" prefWidth="136.0" text="Data" />\n                      <TableColumn fx:id="eventColumn" prefWidth="311.0" text="Evento" />\n                    </columns>\n                     <contextMenu>\n                        <ContextMenu>\n                           <items>\n                              <MenuItem fx:id="removeButton" mnemonicParsing="false" onAction="#removeEvent" text="Rimuovi Evento" />\n                              <MenuItem fx:id="importaButton" mnemonicParsing="false" onAction="#importCSV" text="Importa CSV" />\n                              <MenuItem fx:id="exportButton" mnemonicParsing="false" onAction="#exportCSV" text="Esporta CSV" />\n                           </items>\n                        </ContextMenu>\n                     </contextMenu>\n                  </TableView>\n               </children>\n            </AnchorPane>\n        </items>\n      </SplitPane>\n   </children>\n</fx:root>\n

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所有帮助将不胜感激！

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Answer 1

只是将其标记为已回答：请参阅@James_D'评论以获取解决方案。

<fx:root>在 FXML 文件中替换为或在调用之前<AnchorPane>设置根目录，例如如下所示：FXMLLoaderload()

FXMLLoader fxmlLoader = new FXMLLoader(getClass().getResource("FXMLDocument.fxml"));
fxmlLoader.setRoot(new AnchorPane());
Parent root = fxmlLoader.load();

另请参阅： 设置 root 时的 JavaFx FXML 加载文件问题