java - 输入字符串的 NumberFormatException：“”
问题描述
我在运行我的 JavaFX 数独应用程序时遇到问题。
我有一个void updateBoard()方法，它使用 sudokuBoard 对象并将 textFields 中的数字分配给每个 sudokuBoard 字段。一个 textField 负责一个 sudokuBoard 字段。
public void updateBoard() {
for (int i = 0; i < 9; i++) {
for (int j = 0; j < 9; j++) {
if ((Integer) Integer.parseInt(textFields[i][j].getText()) != null) {
sudokuBoard.set(i, j, Integer.parseInt(textFields[i][j].getText()));
} else {
sudokuBoard.set(i, j, null);
}
index++;
}
}
}
然后我还有一个方法boolean checkBoard()检查数独板是否正确解决。
public boolean checkBoard() {
updateBoard();
int counter = 0;
if (difficultyLevel.getLevel() == 0) {
for (int i = 0; i < 9; i++) {
for (int j = 0; j < 9; j++) {
if (counter % 5 == 0) {
if (sudokuBoard.getValue(i, j) == null) {
return false;
}
if (sudokuBoard.getValue(i, j) != difficultyLevel.getRejectedNumbers()[i][j]) {
return false;
}
}
counter++;
}
}
}
if (difficultyLevel.getLevel() == 1) {
for (int i = 0; i < 9; i++) {
for (int j = 0; j < 9; j++) {
if (counter % 3 == 0) {
if (sudokuBoard.getValue(i, j) == null) {
return false;
}
if (sudokuBoard.getValue(i, j) != difficultyLevel.getRejectedNumbers()[i][j]) {
return false;
}
}
counter++;
}
}
}
if (difficultyLevel.getLevel() == 2) {
for (int i = 0; i < 9; i++) {
for (int j = 0; j < 9; j++) {
if (counter % 2 == 0) {
if (sudokuBoard.getValue(i, j) == null) {
return false;
}
if (sudokuBoard.getValue(i, j) != difficultyLevel.getRejectedNumbers()[i][j]) {
return false;
}
}
counter++;
}
}
}
return true;
}
当我从方法checkBoard()调用方法updateBoard()时，它可以正常工作。
但是，当我调用此方法时（按下按钮后）：
public void saveGameSudokuBoardButtonPushed() throws Exception {
updateBoard();
Stage stage = (Stage) saveGameSudokuBoardButton.getScene().getWindow();
FileChooser fileChooser = new FileChooser();
fileChooser.setTitle("Zapisz plik");
File file = fileChooser.showSaveDialog(stage);
FileSudokuBoardDao fileSudokuBoardDao = null;
try {
fileSudokuBoardDao = (FileSudokuBoardDao) SudokuBoardDaoFactory.getFileDao(file.toPath().toString());
} catch (NullPointerException exception) {
exception.printStackTrace();
}
fileSudokuBoardDao.write(sudokuBoard);
}
我收到以下错误：
Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
at javafx.fxml/javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1787)
at javafx.fxml/javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1670)
at javafx.base/com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at javafx.base/com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at javafx.base/com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
at javafx.base/javafx.event.Event.fireEvent(Event.java:198)
at javafx.graphics/javafx.scene.Node.fireEvent(Node.java:8879)
at javafx.controls/javafx.scene.control.Button.fire(Button.java:200)
at javafx.controls/com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:206)
at javafx.controls/com.sun.javafx.scene.control.inputmap.InputMap.handle(InputMap.java:274)
at javafx.base/com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
at javafx.base/com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at javafx.base/com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at javafx.base/com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.base/javafx.event.Event.fireEvent(Event.java:198)
at javafx.graphics/javafx.scene.Scene$MouseHandler.process(Scene.java:3851)
at javafx.graphics/javafx.scene.Scene$MouseHandler.access$1200(Scene.java:3579)
at javafx.graphics/javafx.scene.Scene.processMouseEvent(Scene.java:1849)
at javafx.graphics/javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2588)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:397)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:295)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:391)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$2(GlassViewEventHandler.java:434)
at javafx.graphics/com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:390)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:433)
at javafx.graphics/com.sun.glass.ui.View.handleMouseEvent(View.java:556)
at javafx.graphics/com.sun.glass.ui.View.notifyMouse(View.java:942)
at javafx.graphics/com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at javafx.graphics/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:174)
at java.base/java.lang.Thread.run(Thread.java:832)
Caused by: java.lang.reflect.InvocationTargetException
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at com.sun.javafx.reflect.Trampoline.invoke(MethodUtil.java:76)
at jdk.internal.reflect.GeneratedMethodAccessor2.invoke(Unknown Source)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at javafx.base/com.sun.javafx.reflect.MethodUtil.invoke(MethodUtil.java:273)
at javafx.fxml/com.sun.javafx.fxml.MethodHelper.invoke(MethodHelper.java:83)
at javafx.fxml/javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1784)
... 47 more
Caused by: java.lang.NumberFormatException: For input string: ""
at java.base/java.lang.NumberFormatException.forInputString(NumberFormatException.java:68)
at java.base/java.lang.Integer.parseInt(Integer.java:662)
at java.base/java.lang.Integer.parseInt(Integer.java:770)
at gui.SudokuBoardController.updateBoard(SudokuBoardController.java:86)
at gui.SudokuBoardController.saveGameSudokuBoardButtonPushed(SudokuBoardController.java:174)
... 58 more
Process finished with exit code 0
我不知道为什么在调用saveGameSudokuBoardButtonPushed()方法时会出现问题，而在调用checkBoard()方法时不会出现问题。
方法saveGameSudokuBoardButtonPushed()在没有调用方法updateBoard()时完美运行。
//编辑//
我应该补充一点，我的数独板已经实现了从数独板中删除某些字段的难度级别。那些被删除的字段被保存在那些难度级别的类中，并且在它们的地方，sudokuBoard 字段中为空。然后 sudokuBoard 字段被分配给 GUI 上的 textFields。因此，当我尝试保存电路板时，某些字段为空是可以的。但是我想知道为什么这取决于我是否在 checkBoard() 方法和 saveGameSudokuBoardButtonPushed() 中使用 updateBoard() 方法，如果它们的实现相同
解决方案
""不能解析成整数。因此，您需要跳过解析空白字符串。你可以这样做：
if (!textFields[i][j].getText().isBlank()) {
sudokuBoard.set(i, j, Integer.parseInt(textFields[i][j].getText()));
}
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