在main中加载fxml文件

问题描述 投票：0回答：2

我从 youtube 上完成了这个教程，我的代码与教程相同，但我使用 Scenebuilder 做了正确的 fxml。 这是代码：https://github.com/AlmasB/FXTutorials/tree/master/src/com/almasb/calc 我有相同的主控、相同的控制器和相同的型号.. 当我尝试编译时，它对我说：

`Exception in Application start method
java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(Unknown Source)
    at com.sun.javafx.application.LauncherImpl.launchApplication(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at sun.launcher.LauncherHelper$FXHelper.main(Unknown Source)
Caused by: java.lang.RuntimeException: Exception in Application start method
    at com.sun.javafx.application.LauncherImpl.launchApplication1(Unknown Source)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$147(Unknown Source)
    at com.sun.javafx.application.LauncherImpl$$Lambda$48/1394438858.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NullPointerException: Location is required.
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
    at javafx.fxml.FXMLLoader.load(Unknown Source)
    at application.Main.start(Main.java:12)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$153(Unknown Source)
    at com.sun.javafx.application.LauncherImpl$$Lambda$51/1252716230.run(Unknown Source)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$166(Unknown Source)
    at com.sun.javafx.application.PlatformImpl$$Lambda$45/1775282465.run(Unknown Source)
    at com.sun.javafx.application.PlatformImpl.lambda$null$164(Unknown Source)
    at com.sun.javafx.application.PlatformImpl$$Lambda$47/21202996.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$165(Unknown Source)
    at com.sun.javafx.application.PlatformImpl$$Lambda$46/2040495657.run(Unknown Source)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(Unknown Source)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$141(Unknown Source)
    at com.sun.glass.ui.win.WinApplication$$Lambda$37/1558600329.run(Unknown Source)
    ... 1 more
Exception running application application.Main

package application;

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

这是我的主要:

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

public class Main extends Application {

    @Override
    public void start(Stage primaryStage) {
       try {
        FXMLLoader loader = new FXMLLoader(getClass().getResource("view/Calculatorview.fxml"));
  //    Parent root = FXMLLoader.load(getClass().getResource("view/Calculatorview.fxml"));
        AnchorPane root = (AnchorPane) 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);
    }
}

这是我的 fxml 文件：

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

<?import javafx.embed.swing.*?>
<?import javafx.scene.effect.*?>
<?import javafx.scene.text.*?>
<?import javafx.scene.control.*?>
<?import java.lang.*?>
<?import javafx.scene.layout.*?>
<?import javafx.scene.layout.AnchorPane?>

<fx:root maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0" prefWidth="640.0" type="AnchorPane" xmlns="http://javafx.com/javafx/8.0.40" xmlns:fx="http://javafx.com/fxml/1" fx:controller="application.Controller">
   <children>
      <AnchorPane prefHeight="600.0" prefWidth="700.0" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0">
         <children>
            <SplitPane dividerPositions="0.19063545150501673" layoutX="149.0" layoutY="32.0" orientation="VERTICAL" prefHeight="600.0" prefWidth="500.0" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0">
              <items>
                <AnchorPane minHeight="0.0" minWidth="0.0" prefHeight="100.0" prefWidth="160.0">
                     <children>
                        <TextField alignment="CENTER_RIGHT" prefHeight="73.0" prefWidth="638.0" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0">
                           <font>
                              <Font size="47.0" />
                           </font>
                        </TextField>
                     </children>
                  </AnchorPane>
                <AnchorPane minHeight="0.0" minWidth="0.0" prefHeight="515.0" prefWidth="498.0">
                     <children>
                        <GridPane layoutX="90.0" layoutY="116.0" prefHeight="319.0" prefWidth="638.0" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0">
                          <columnConstraints>
                              <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
                            <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
                              <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
                              <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
                              <ColumnConstraints hgrow="SOMETIMES" maxWidth="116.0" minWidth="10.0" prefWidth="95.0" />
                              <ColumnConstraints hgrow="SOMETIMES" maxWidth="116.0" minWidth="10.0" prefWidth="95.0" />
                              <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
                              <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
                          </columnConstraints>
                          <rowConstraints>
                              <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
                            <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
                            <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
                              <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
                            <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
                          </rowConstraints>
                           <effect>
                              <Blend />
                           </effect>
                           <children>
                              <Button mnemonicParsing="false" onAction="#processOperator" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #EE543A; -fx-text-fill: #FFFFFF;" text="=" GridPane.columnIndex="7" GridPane.rowIndex="4">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button layoutX="620.0" layoutY="395.0" mnemonicParsing="false" onAction="#processOperator" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #EE543A; -fx-text-fill: #FFFFFF;" text="+" GridPane.columnIndex="7" GridPane.rowIndex="3">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button layoutX="620.0" layoutY="299.0" mnemonicParsing="false" onAction="#processOperator" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #EE543A; -fx-text-fill: #FFFFFF;" text="-" GridPane.columnIndex="7" GridPane.rowIndex="2">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button layoutX="620.0" layoutY="203.0" mnemonicParsing="false" onAction="#processOperator" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #EE543A; -fx-text-fill: #FFFFFF;" text="×" GridPane.columnIndex="7" GridPane.rowIndex="1">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button layoutX="620.0" layoutY="107.0" mnemonicParsing="false" onAction="#processOperator" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #EE543A; -fx-text-fill: #FFFFFF;" text="÷" GridPane.columnIndex="7">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button layoutX="532.0" layoutY="395.0" mnemonicParsing="false" prefHeight="70.0" prefWidth="76.0" style="-fx-background-color: #60646D; -fx-text-fill: #FFFFFF;" text="C" GridPane.columnIndex="4" GridPane.rowIndex="4">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button layoutX="358.0" layoutY="395.0" mnemonicParsing="false" onAction="#processNumpad" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #9E9D9B; -fx-text-fill: #FFFFFF;" text="0" GridPane.columnIndex="5" GridPane.rowIndex="4">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button layoutX="362.0" layoutY="395.0" mnemonicParsing="false" prefHeight="69.0" prefWidth="88.0" style="-fx-background-color: #60646D; -fx-text-fill: #FFFFFF;" text="M-" GridPane.columnIndex="4">
                                 <font>
                                    <Font size="28.0" />
                                 </font>
                              </Button>
                              <Button layoutX="10.0" layoutY="11.0" mnemonicParsing="false" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #60646D; -fx-text-fill: #FFFFFF;" text="e" GridPane.columnIndex="1" GridPane.rowIndex="4">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button layoutX="10.0" layoutY="11.0" mnemonicParsing="false" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #60646D; -fx-text-fill: #FFFFFF;" text="1/x" GridPane.columnIndex="3" GridPane.rowIndex="4">
                                 <font>
                                    <Font name="System" size="28.0" />
                                 </font>
                              </Button>
                              <Button layoutX="10.0" layoutY="11.0" mnemonicParsing="false" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #60646D; -fx-text-fill: #FFFFFF;" text="√" GridPane.columnIndex="3" GridPane.rowIndex="3">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button layoutX="10.0" layoutY="11.0" mnemonicParsing="false" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #60646D; -fx-text-fill: #FFFFFF;" text="MC" GridPane.columnIndex="3" GridPane.rowIndex="2">
                                 <font>
                                    <Font name="System" size="28.0" />
                                 </font>
                              </Button>
                              <Button layoutX="10.0" layoutY="11.0" mnemonicParsing="false" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #60646D; -fx-text-fill: #FFFFFF;" text="M+" GridPane.columnIndex="3" GridPane.rowIndex="1">
                                 <font>
                                    <Font size="27.0" />
                                 </font>
                              </Button>
                              <Button layoutX="10.0" layoutY="11.0" mnemonicParsing="false" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #60646D; -fx-text-fill: #FFFFFF;" text="x²" GridPane.columnIndex="2" GridPane.rowIndex="3">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button layoutX="10.0" layoutY="11.0" mnemonicParsing="false" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #60646D; -fx-text-fill: #FFFFFF;" text="tan" GridPane.columnIndex="2" GridPane.rowIndex="2">
                                 <font>
                                    <Font name="System" size="28.0" />
                                 </font>
                              </Button>
                              <Button layoutX="10.0" layoutY="11.0" mnemonicParsing="false" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #60646D; -fx-text-fill: #FFFFFF;" text="sin" GridPane.columnIndex="2" GridPane.rowIndex="1">
                                 <font>
                                    <Font name="System" size="30.0" />
                                 </font>
                              </Button>
                              <Button layoutX="10.0" layoutY="11.0" mnemonicParsing="false" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #60646D; -fx-text-fill: #FFFFFF;" text="xʸ" GridPane.rowIndex="4">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button layoutX="10.0" layoutY="11.0" mnemonicParsing="false" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #60646D; -fx-text-fill: #FFFFFF;" text="log" GridPane.rowIndex="2">
                                 <font>
                                    <Font name="System" size="28.0" />
                                 </font>
                              </Button>
                              <Button graphicTextGap="0.0" layoutX="10.0" layoutY="11.0" mnemonicParsing="false" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #60646D; -fx-text-fill: #FFFFFF;" text="cos" GridPane.columnIndex="2">
                                 <font>
                                    <Font name="System" size="26.0" />
                                 </font>
                              </Button>
                              <Button layoutX="10.0" layoutY="11.0" mnemonicParsing="false" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #60646D; -fx-text-fill: #FFFFFF;" text=")">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button alignment="CENTER" layoutX="10.0" layoutY="11.0" mnemonicParsing="false" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #60646D; -fx-text-fill: #FFFFFF;" text="x³" GridPane.columnIndex="2" GridPane.rowIndex="4">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button layoutX="98.0" layoutY="11.0" mnemonicParsing="false" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #60646D; -fx-text-fill: #FFFFFF;" text="(" GridPane.rowIndex="1">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button layoutX="10.0" layoutY="11.0" mnemonicParsing="false" onAction="#processNumpad" prefHeight="64.0" prefWidth="95.0" style="-fx-background-color: #9E9D9B; -fx-text-fill: #FFFFFF;" text="3" GridPane.columnIndex="6" GridPane.rowIndex="3">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button layoutX="10.0" layoutY="11.0" mnemonicParsing="false" onAction="#processNumpad" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #9E9D9B; -fx-text-fill: #FFFFFF;" text="2" GridPane.columnIndex="5" GridPane.rowIndex="3">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button layoutX="10.0" layoutY="11.0" mnemonicParsing="false" onAction="#processNumpad" prefHeight="64.0" prefWidth="96.0" style="-fx-background-color: #9E9D9B; -fx-text-fill: #FFFFFF;" text="6" GridPane.columnIndex="6" GridPane.rowIndex="2">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button layoutX="10.0" layoutY="11.0" mnemonicParsing="false" onAction="#processNumpad" prefHeight="64.0" prefWidth="98.0" style="-fx-background-color: #9E9D9B; -fx-text-fill: #FFFFFF;" text="9" GridPane.columnIndex="6" GridPane.rowIndex="1">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button layoutX="10.0" layoutY="11.0" mnemonicParsing="false" onAction="#processNumpad" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #9E9D9B; -fx-text-fill: #FFFFFF;" text="8" GridPane.columnIndex="5" GridPane.rowIndex="1">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button layoutX="10.0" layoutY="11.0" mnemonicParsing="false" prefHeight="64.0" prefWidth="96.0" style="-fx-background-color: #60646D; -fx-text-fill: #FFFFFF;" text="±" GridPane.columnIndex="5">
                                 <font>
                                    <Font size="29.0" />
                                 </font>
                              </Button>
                              <Button layoutX="10.0" layoutY="11.0" mnemonicParsing="false" onAction="#processNumpad" prefHeight="58.0" prefWidth="76.0" style="-fx-background-color: #9E9D9B; -fx-text-fill: #FFFFFF;" text="1" GridPane.columnIndex="4" GridPane.rowIndex="3">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button layoutX="10.0" layoutY="11.0" mnemonicParsing="false" onAction="#processNumpad" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #9E9D9B; -fx-text-fill: #FFFFFF;" text="4" GridPane.columnIndex="4" GridPane.rowIndex="2">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button layoutX="10.0" layoutY="11.0" mnemonicParsing="false" onAction="#processNumpad" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #9E9D9B; -fx-text-fill: #FFFFFF;" text="5" GridPane.columnIndex="5" GridPane.rowIndex="2">
                                 <font>
                                    <Font size="35.0" />
                                 </font>
                              </Button>
                              <Button layoutX="10.0" layoutY="11.0" mnemonicParsing="false" onAction="#processNumpad" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #9E9D9B; -fx-text-fill: #FFFFFF;" text="7" GridPane.columnIndex="4" GridPane.rowIndex="1">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button layoutX="619.0" layoutY="395.0" mnemonicParsing="false" prefHeight="100.0" prefWidth="81.0" style="-fx-background-color: #EE543A; -fx-text-fill: #FFFFFF;" text="\%" GridPane.columnIndex="6">
                                 <font>
                                    <Font size="29.0" />
                                 </font>
                              </Button>
                              <Button mnemonicParsing="false" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #60646D; -fx-text-fill: #FFFFFF;" text="π" GridPane.rowIndex="3">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button layoutX="462.0" layoutY="202.0" mnemonicParsing="false" onAction="#processNumpad" prefHeight="64.0" prefWidth="95.0" style="-fx-background-color: #9E9D9B; -fx-text-fill: #FFFFFF;" text="." GridPane.columnIndex="6" GridPane.rowIndex="4">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button graphicTextGap="0.0" layoutX="172.0" layoutY="10.0" mnemonicParsing="false" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #60646D; -fx-text-fill: #FFFFFF;" text="cosh" GridPane.columnIndex="1">
                                 <font>
                                    <Font name="System" size="22.0" />
                                 </font>
                              </Button>
                              <Button layoutX="172.0" layoutY="74.0" mnemonicParsing="false" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #60646D; -fx-text-fill: #FFFFFF;" text="sinh" GridPane.columnIndex="1" GridPane.rowIndex="1">
                                 <font>
                                    <Font size="25.0" />
                                 </font>
                              </Button>
                              <Button layoutX="172.0" layoutY="138.0" mnemonicParsing="false" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #60646D; -fx-text-fill: #FFFFFF;" text="tanh" GridPane.columnIndex="1" GridPane.rowIndex="2">
                                 <font>
                                    <Font name="System" size="24.0" />
                                 </font>
                              </Button>
                              <Button layoutX="91.0" layoutY="266.0" mnemonicParsing="false" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #60646D; -fx-text-fill: #FFFFFF;" text="10ʸ" GridPane.columnIndex="1" GridPane.rowIndex="3">
                                 <font>
                                    <Font size="30.0" />
                                 </font>
                              </Button>
                              <Button layoutX="253.0" layoutY="74.0" mnemonicParsing="false" prefHeight="96.0" prefWidth="92.0" style="-fx-background-color: #60646D; -fx-text-fill: #FFFFFF;" text="MR" GridPane.columnIndex="3">
                                 <font>
                                    <Font size="28.0" />
                                 </font>
                              </Button>
                           </children>
                        </GridPane>
                     </children>
                  </AnchorPane>
              </items>
            </SplitPane>
         </children>
      </AnchorPane>
   </children>
</fx:root>

新主线： file structure

java javafx fxml scenebuilder
2个回答
3
投票

好吧。我尝试使用 Java 1.8 设置我的环境，并尝试了提供的链接中的教程。这就是我所做的。

  1. 已安装 Elcipse Kepler (Java EE)
  2. 遵循此处的 e(fx)clipse 说明 https://www.eclipse.org/efxclipse/install.html
  3. 安装了所有库/jar，如下所示

完成上述操作后，我在 eclipse 中创建了一个新的 Java 项目。我右键单击该项目并创建了两个源文件夹，即

src/main/java 
src/main/resources

然后我右键单击 src/main/java 并创建新包并将其命名为 application。在应用程序下，我创建了 4 个 java 类，并复制了教程链接中的内容。我确实修改了每个 java 文件顶部的包以仅反映 application。

这是java类

package application;

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

public class App extends Application {

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

        primaryStage.setScene(new Scene(root));
        primaryStage.show();
    }

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

控制器

 package application;

import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.scene.control.Button;
import javafx.scene.text.Text;

public class Controller {

    @FXML
    private Text output;

    private long number1 = 0;
    private String operator = "";
    private boolean start = true;

    private Model model = new Model();

    @FXML
    private void processNumpad(ActionEvent event) {
        if (start) {
            output.setText("");
            start = false;
        }

        String value = ((Button)event.getSource()).getText();
        output.setText(output.getText() + value);
    }

    @FXML
    private void processOperator(ActionEvent event) {
        String value = ((Button)event.getSource()).getText();

        if (!"=".equals(value)) {
            if (!operator.isEmpty())
                return;

            operator = value;
            number1 = Long.parseLong(output.getText());
            output.setText("");
        }
        else {
            if (operator.isEmpty())
                return;

            output.setText(String.valueOf(model.calculate(number1, Long.parseLong(output.getText()), operator)));
            operator = "";
            start = true;
        }
    }
}

型号

package application;

public class Model {

    public long calculate(long number1, long number2, String operator) {
        switch (operator) {
            case "+":
                return number1 + number2;
            case "-":
                return number1 - number2;
            case "*":
                return number1 * number2;
            case "/":
                if (number2 == 0)
                    return 0;

                return number1 / number2;
        }

        System.out.println("Unknown operator - " + operator);
        return 0;
    }
}

和 ui.fxml 

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

<?import java.net.*?>
<?import java.lang.*?>
<?import java.util.*?>
<?import javafx.beans.property.*?>
<?import javafx.geometry.*?>
<?import javafx.scene.shape.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.image.*?>
<?import javafx.scene.layout.*?>
<?import javafx.scene.text.*?>
<?import javafx.scene.paint.Color?>

<VBox spacing="10" alignment="CENTER" prefWidth="300" prefHeight="300" fx:controller="application.Controller" xmlns:fx="http://javafx.com/fxml">
    <fx:define>
        <Font fx:id="FONT" size="18" />
    </fx:define>

    <StackPane alignment="CENTER">
        <Rectangle fill="TRANSPARENT" stroke="GRAY" width="230" height="50" />
        <Text fx:id="output" font="$FONT" />
    </StackPane>

    <HBox spacing="10" alignment="CENTER">
        <Button text="7" prefWidth="50" font="$FONT" onAction="#processNumpad" />
        <Button text="8" prefWidth="50" font="$FONT" onAction="#processNumpad" />
        <Button text="9" prefWidth="50" font="$FONT" onAction="#processNumpad" />
        <Button text="/" prefWidth="50" font="$FONT" onAction="#processOperator" />
    </HBox>

    <HBox spacing="10" alignment="CENTER">
        <Button text="4" prefWidth="50" font="$FONT" onAction="#processNumpad" />
        <Button text="5" prefWidth="50" font="$FONT" onAction="#processNumpad" />
        <Button text="6" prefWidth="50" font="$FONT" onAction="#processNumpad" />
        <Button text="*" prefWidth="50" font="$FONT" onAction="#processOperator" />
    </HBox>

    <HBox spacing="10" alignment="CENTER">
        <Button text="1" prefWidth="50" font="$FONT" onAction="#processNumpad" />
        <Button text="2" prefWidth="50" font="$FONT" onAction="#processNumpad" />
        <Button text="3" prefWidth="50" font="$FONT" onAction="#processNumpad" />
        <Button text="-" prefWidth="50" font="$FONT" onAction="#processOperator" />
    </HBox>

    <HBox spacing="10" alignment="CENTER">
        <Button text="0" prefWidth="110" font="$FONT" onAction="#processNumpad" />
        <Button text="=" prefWidth="50" font="$FONT" onAction="#processOperator" />
        <Button text="+" prefWidth="50" font="$FONT" onAction="#processOperator" />
    </HBox>

</VBox>

我遇到了 Java 源库（参考 JRE）和 jfxrt.jar 文件的问题。所以我做了以下

  1. 删除了引用的库
  2. 删除了引用的外部jar
  3. 右键单击该项目并选择属性
  4. 选择Java构建路径
  5. 点击窗口右侧的Add Library，添加JRE System Library，如下图
  6. 添加了外部 jar jfxrt.jar

添加上面之后，代码就解决了，没有任何问题。

记住，我将 ui.fxml 放在 src/main/resources 文件夹下。因此，当我最初以 Java Application 运行该项目时，它会抱怨并给出与您所面临的相同的异常。所以我将“ui.fxml”更改为“/ui.fxml”，然后，我看到了计算器。 

Parent root = FXMLLoader.load(getClass().getResource("/ui.fxml"));

请参见下面的屏幕截图，我希望这些步骤有所帮助。

2
投票
NullPointerException：需要位置

从您调用的行开始 

FXMLLoader.load(...)
表示您为 FXML 文件提供的 URL 是 
null
：即资源的路径不正确。

getClass().getResource()
将在类路径上搜索相对于当前类的资源。根据您链接的屏幕截图，
Main
位于包
appication
中，
Calculatorview.fxml
位于
application.view
中。所以你需要

Parent root = FXMLLoader.load(getClass().getResource("view/Calculatorview.fxml"));

或者，您可以指定相对于类路径（而不是相对于当前类）的 fxml 文件：

Parent root = FXMLLoader.load(getClass().getResource("/application/view/Calculatorview.fxml"));

（注意与您的代码相比额外的前导 

/
）。

当然，请注意，该路径是在运行时搜索的，因此您需要确保在编译代码时将 fxml 文件与 class 文件一起部署。换句话说，如果 

Main
和 
Calculatorview.fxml
位于包 
application
中，那么某个地方应该有一个名为 
application
的文件夹，其中包含 
Main.class
（注意，类文件）和 
Calculatorview.fxml
。这通常位于名为 
bin
或 
classes
的文件夹中，具体取决于您的 IDE 及其设置（或者，如果您正在构建 jar，您将在 jar 文件中拥有 
application
结构）。

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