Java 运行application.TipCalculator时出现异常

所以我从教科书中得到了在eclipse中使用的代码，它实际上不会运行基本代码，即使我做了教授让我做的一切。我在运行application.TipCalculator时遇到一个错误异常，我不知道该怎么办。第一个代码段是我的主代码段，第二个是我的控制器，第三个是我的xml文件

TipCalculator.java

package application;


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

public class TipCalculator extends Application {
   @Override
   public void start(Stage stage) throws Exception {
       Parent root = FXMLLoader.load(getClass().getResource("/TipCalculator.fxml"));

      Scene scene = new Scene(root); // attach scene graph to scene
      stage.setTitle("Tip Calculator"); // displayed in window's title bar
      stage.setScene(scene); // attach scene to stage
      stage.show(); // display the stage
   }

   public static void main(String[] args) {
      // create a TipCalculator object and call its start method
      launch(args); 
   }
}

TipCalculatorController.java

package application;

import java.math.BigDecimal;
import java.math.RoundingMode;
import java.text.NumberFormat;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.scene.control.Label;
import javafx.scene.control.Slider;
import javafx.scene.control.TextField;

public class TipCalculatorController { 
   // formatters for currency and percentages
   private static final NumberFormat currency = 
      NumberFormat.getCurrencyInstance();
   private static final NumberFormat percent = 
      NumberFormat.getPercentInstance();
   
   private BigDecimal tipPercentage = new BigDecimal(0.15); // 15% default
   
   // GUI controls defined in FXML and used by the controller's code
   @FXML 
   private TextField amountTextField; 

   @FXML
   private Label tipPercentageLabel; 

   @FXML
   private Slider tipPercentageSlider;

   @FXML
   private TextField tipTextField;

   @FXML
   private TextField totalTextField;

   // calculates and displays the tip and total amounts
   @FXML
   private void calculateButtonPressed(ActionEvent event) {
      try {
         BigDecimal amount = new BigDecimal(amountTextField.getText());
         BigDecimal tip = amount.multiply(tipPercentage);
         BigDecimal total = amount.add(tip);

         tipTextField.setText(currency.format(tip));
         totalTextField.setText(currency.format(total));
      }
      catch (NumberFormatException ex) {
         amountTextField.setText("Enter amount");
         amountTextField.selectAll();
         amountTextField.requestFocus();
      }
   }

   // called by FXMLLoader to initialize the controller
   public void initialize() {
      // 0-4 rounds down, 5-9 rounds up 
      currency.setRoundingMode(RoundingMode.HALF_UP);
      
      // listener for changes to tipPercentageSlider's value
      tipPercentageSlider.valueProperty().addListener(
         new ChangeListener<Number>() {
            @Override
            public void changed(ObservableValue<? extends Number> ov, 
               Number oldValue, Number newValue) {
               tipPercentage = 
                  BigDecimal.valueOf(newValue.intValue() / 100.0);
               tipPercentageLabel.setText(percent.format(tipPercentage));
            }
         }
      );
   }
}

---

请帮助。

首先，您需要更改在

应用程序中添加的控制器

软件包：

注意：

将

/

设置为从src文件夹读取，因为它们不在同一个包中

TipController

更改此项：

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

到

然后更改指定控制器路径的fxml文件：

TipCalculator.fxml

<GridPane hgap="8.0" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" xmlns="http://javafx.com/javafx/8.0.60" xmlns:fx="http://javafx.com/fxml/1" fx:controller="application.TipCalculatorController">

完整代码：

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

<?import javafx.geometry.Insets?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.control.Slider?>
<?import javafx.scene.control.TextField?>
<?import javafx.scene.layout.ColumnConstraints?>
<?import javafx.scene.layout.GridPane?>
<?import javafx.scene.layout.RowConstraints?>

<GridPane hgap="8.0" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" xmlns="http://javafx.com/javafx/8.0.60" xmlns:fx="http://javafx.com/fxml/1" fx:controller="application.TipCalculatorController">
   <columnConstraints>
      <ColumnConstraints halignment="RIGHT" hgrow="SOMETIMES" minWidth="10.0" />
      <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" />
   </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>
   <children>
      <Label text="Amount" />
      <Label fx:id="tipPercentageLabel" text="15%" GridPane.rowIndex="1" />
      <Label text="Tip" GridPane.rowIndex="2" />
      <Label text="Total" GridPane.rowIndex="3" />
      <TextField fx:id="amountTextField" GridPane.columnIndex="1" />
      <TextField fx:id="tipTextField" editable="false" focusTraversable="false" GridPane.columnIndex="1" GridPane.rowIndex="2" />
      <TextField fx:id="totalTextField" editable="false" focusTraversable="false" GridPane.columnIndex="1" GridPane.rowIndex="3" />
      <Slider fx:id="tipPercentageSlider" blockIncrement="5.0" max="30.0" value="15.0" GridPane.columnIndex="1" GridPane.rowIndex="1" />
      <Button maxWidth="1.7976931348623157E308" mnemonicParsing="false" onAction="#calculateButtonPressed" text="Calculate" GridPane.columnIndex="1" GridPane.rowIndex="4" />
   </children>
   <padding>
      <Insets bottom="14.0" left="14.0" right="14.0" top="14.0" />
   </padding>
</GridPane>

您是否在同一个包中定义了所有文件？或者它们在默认包中？我相信是的，这是程序包的gyazo。我应该将父根行放在哪里？我尝试了这些更改，但仍然得到了相同的错误，非常感谢您的帮助。尝试使用应用于代码的新更改更新代码。@CSCSCStudent77更新了代码，问题在于您的fxml文件，因此我添加了完整的fxml文件done and done，虽然我没有足够的名声让它出现，哈哈

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

<GridPane hgap="8.0" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" xmlns="http://javafx.com/javafx/8.0.60" xmlns:fx="http://javafx.com/fxml/1" fx:controller="application.TipCalculatorController">

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

<?import javafx.geometry.Insets?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.control.Slider?>
<?import javafx.scene.control.TextField?>
<?import javafx.scene.layout.ColumnConstraints?>
<?import javafx.scene.layout.GridPane?>
<?import javafx.scene.layout.RowConstraints?>

<GridPane hgap="8.0" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" xmlns="http://javafx.com/javafx/8.0.60" xmlns:fx="http://javafx.com/fxml/1" fx:controller="application.TipCalculatorController">
   <columnConstraints>
      <ColumnConstraints halignment="RIGHT" hgrow="SOMETIMES" minWidth="10.0" />
      <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" />
   </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>
   <children>
      <Label text="Amount" />
      <Label fx:id="tipPercentageLabel" text="15%" GridPane.rowIndex="1" />
      <Label text="Tip" GridPane.rowIndex="2" />
      <Label text="Total" GridPane.rowIndex="3" />
      <TextField fx:id="amountTextField" GridPane.columnIndex="1" />
      <TextField fx:id="tipTextField" editable="false" focusTraversable="false" GridPane.columnIndex="1" GridPane.rowIndex="2" />
      <TextField fx:id="totalTextField" editable="false" focusTraversable="false" GridPane.columnIndex="1" GridPane.rowIndex="3" />
      <Slider fx:id="tipPercentageSlider" blockIncrement="5.0" max="30.0" value="15.0" GridPane.columnIndex="1" GridPane.rowIndex="1" />
      <Button maxWidth="1.7976931348623157E308" mnemonicParsing="false" onAction="#calculateButtonPressed" text="Calculate" GridPane.columnIndex="1" GridPane.rowIndex="4" />
   </children>
   <padding>
      <Insets bottom="14.0" left="14.0" right="14.0" top="14.0" />
   </padding>
</GridPane>