我有一些直接来自Java 8教科书的代码。我的任务是编辑代码，但是我无法运行基本代码。 文件包括TipCalculator.java，TipCalculatorController.java和TipCalculator.fxml
我不是在寻求实际分配的帮助。只是有关如何使代码不出错的提示。
我在Eclipse Photon和Neon中遇到相同的错误。
我在Eclipse中创建一个新的> Project> JavaFX Project。
LoadException显示第12行，即@Override行，但它显示了正确放置在项目中的TipCalculator.fxml文件路径。是的，.fxml文件已复制到应用程序区域中。我尝试了FXMLLoader.load（getClass（）。getResource（“ TipCalculator.fxml”）））的所有变体；我可以找到。没有任何东西可以消除错误。而且由于它是直接来自本书的，因此我认为它不需要任何更改。 与本书代码唯一不同的是.java文件顶部的“打包应用程序”。本书的代码没有，但是会自动在我的应用程序类中弹出。
TipCalculator.java
package application;
//Fig. 12.19: TipCalculator.java
//Main application class that loads and displays the Tip Calculator's GUI.
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);
}
}
/**************************************************************************
* (C) Copyright 1992-2018 by Deitel & Associates, Inc. and *
* Pearson Education, Inc. All Rights Reserved. *
* *
* DISCLAIMER: The authors and publisher of this book have used their *
* best efforts in preparing the book. These efforts include the *
* development, research, and testing of the theories and programs *
* to determine their effectiveness. The authors and publisher make *
* no warranty of any kind, expressed or implied, with regard to these *
* programs or to the documentation contained in these books. The authors *
* and publisher shall not be liable in any event for incidental or *
* consequential damages in connection with, or arising out of, the *
* furnishing, performance, or use of these programs. *
*************************************************************************/
TipCalculatorController.java
package application;
//TipCalculatorController.java
//Controller that handles calculateButton and tipPercentageSlider events
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));
}
}
);
}
}
/**************************************************************************
* (C) Copyright 1992-2018 by Deitel & Associates, Inc. and *
* Pearson Education, Inc. All Rights Reserved. *
* *
* DISCLAIMER: The authors and publisher of this book have used their *
* best efforts in preparing the book. These efforts include the *
* development, research, and testing of the theories and programs *
* to determine their effectiveness. The authors and publisher make *
* no warranty of any kind, expressed or implied, with regard to these *
* programs or to the documentation contained in these books. The authors *
* and publisher shall not be liable in any event for incidental or *
* consequential damages in connection with, or arising out of, the *
* furnishing, performance, or use of these programs. *
*************************************************************************/
TipCalculator.fxml
<?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="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>
StackTrace
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(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(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at sun.launcher.LauncherHelper$FXHelper.main(Unknown Source)
Caused by: java.lang.RuntimeException: Exception in Application start method
at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$154(LauncherImpl.java:182)
at java.lang.Thread.run(Unknown Source)
Caused by: javafx.fxml.LoadException:
/C:/Users/Carl/workspace2/TipCalculatorAttempt5/bin/application/TipCalculator.fxml:12
at javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2601)
at javafx.fxml.FXMLLoader.access$700(FXMLLoader.java:103)
at javafx.fxml.FXMLLoader$ValueElement.processAttribute(FXMLLoader.java:922)
at javafx.fxml.FXMLLoader$InstanceDeclarationElement.processAttribute(FXMLLoader.java:971)
at javafx.fxml.FXMLLoader$Element.processStartElement(FXMLLoader.java:220)
at javafx.fxml.FXMLLoader$ValueElement.processStartElement(FXMLLoader.java:744)
at javafx.fxml.FXMLLoader.processStartElement(FXMLLoader.java:2707)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2527)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3214)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3175)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3148)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3124)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3104)
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:3097)
at application.TipCalculator.start(TipCalculator.java:15)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$161(LauncherImpl.java:863)
at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$174(PlatformImpl.java:326)
at com.sun.javafx.application.PlatformImpl.lambda$null$172(PlatformImpl.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.application.PlatformImpl.lambda$runLater$173(PlatformImpl.java:294)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
... 1 more
Caused by: java.lang.ClassNotFoundException: TipCalculatorController
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at javafx.fxml.FXMLLoader$ValueElement.processAttribute(FXMLLoader.java:920)
... 22 more
Exception running application application.TipCalculator