Java ComboBox onAction方法导致ClassCastException引起的InvocationTargetException

得到了组合框和一些其他外汇项目

<ComboBox fx:id="YearComboBox" editable="true" layoutX="565.0" layoutY="14.0" onAction="#handleYear" prefWidth="150.0" promptText="Year" />

其中一些已经有了onAction方法，例如ChoiceBox工作正常，但ComboBox的行为很奇怪，因为它似乎调用onAction方法两次：在选择某个值和单击任何其他FX项（如按钮或选择框）时。当我将它打印到控制台时，它会出现两次：在combobox上执行某些操作时，第二次在另一个项目上执行某些操作时，并且不会引发异常，但是当我尝试将is的值赋给te变量时，我会得到异常，比如说“离开”combobox。已经搜索并找到了一些关于ComboBox相关bug的信息，但我认为这是关于其他方面的，为什么异常是由ClassCastException引起的？那么，原木“谈论”的是什么弦乐？ 重要提示：只有单击任何其他JavaFX项（按钮、选择框等）时，才会出现此错误

---

YearComboBox.getSelectionModel（）.getSelectedItem（）

正在返回一个

字符串。因此，尝试将其强制转换为
int
（系统将其重新解释为强制转换为
Integer
，然后取消装箱）失败。您应该改为使用
Integer.parseInt（YearComboBox.getSelectionModel（）.getSelectedItem（）.toString（））
，即使这样，您也需要准备好处理
NumberFormatException
，如果用户输入的数据不是整数的有效字符串表示形式，就会出现这种异常。
方法parseInt（string）在类型Integer不适用于参数（对象）的情况下，仅当“离开”组合框并单击另一个按钮等时才会出现问题。添加
toString（）
调用（应答更新）或将结果强制转换为
字符串，因为实际上就是这样。异常的时间与它的性质无关，这一点从发布的堆栈跟踪中可以清楚地看到。
addAll
的参数是
int
s autoboxed to
Integer
。由于选择模型应该使用
项目
列表中的项目，因此不需要进行字符串转换。（不用说，我无法用问题中提供的代码重现问题…@fabian只需添加一些随机按钮，即使没有onAction方法。当从组合框中选择某个位置时，一切正常，但在选择某个位置后，当您单击“随机”按钮时，组合框似乎再次调用它的操作（为什么？），然后抛出上述异常。@Sheb当您指定
editable=“true”
，可能会从文本字段触发更新，其内容是字符串。您负责指定如何将文本用户输入转换为域的对象。请看……与您的问题无关：请学习java命名约定并坚持它们。
        @FXML
        public void initialize(){
            YearComboBox.getItems().addAll(Calendar.getInstance().get(Calendar.YEAR)-1,Calendar.getInstance().get(Calendar.YEAR),Calendar.getInstance().get(Calendar.YEAR)+1);
            //setting another buttons etc.
        }

        @FXML
        private void handleYear() {
            System.out.println(YearComboBox.getSelectionModel().getSelectedItem());
            year = (int) YearComboBox.getSelectionModel().getSelectedItem();
        }

Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
    at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1774)
    at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1657)
    at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
    at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
    at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
    at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
    at javafx.event.Event.fireEvent(Event.java:198)
    at javafx.scene.Node.fireEvent(Node.java:8411)
    at com.sun.javafx.scene.control.skin.ComboBoxListViewSkin.handleControlPropertyChanged(ComboBoxListViewSkin.java:179)
    at com.sun.javafx.scene.control.skin.BehaviorSkinBase.lambda$registerChangeListener$70(BehaviorSkinBase.java:197)
    at com.sun.javafx.scene.control.MultiplePropertyChangeListenerHandler$1.changed(MultiplePropertyChangeListenerHandler.java:55)
    at javafx.beans.value.WeakChangeListener.changed(WeakChangeListener.java:89)
    at com.sun.javafx.binding.ExpressionHelper$Generic.fireValueChangedEvent(ExpressionHelper.java:361)
    at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:81)
    at javafx.beans.property.ObjectPropertyBase.fireValueChangedEvent(ObjectPropertyBase.java:105)
    at javafx.beans.property.ObjectPropertyBase.markInvalid(ObjectPropertyBase.java:112)
    at javafx.beans.property.ObjectPropertyBase.set(ObjectPropertyBase.java:146)
    at javafx.scene.control.ComboBoxBase.setValue(ComboBoxBase.java:150)
    at com.sun.javafx.scene.control.skin.ComboBoxPopupControl.setTextFromTextFieldIntoComboBoxValue(ComboBoxPopupControl.java:405)
    at com.sun.javafx.scene.control.skin.ComboBoxPopupControl.lambda$new$291(ComboBoxPopupControl.java:82)
    at com.sun.javafx.binding.ExpressionHelper$Generic.fireValueChangedEvent(ExpressionHelper.java:361)
    at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:81)
    at javafx.beans.property.ReadOnlyBooleanPropertyBase.fireValueChangedEvent(ReadOnlyBooleanPropertyBase.java:72)
    at javafx.scene.Node$FocusedProperty.notifyListeners(Node.java:7718)
    at javafx.scene.Scene$13.invalidated(Scene.java:2077)
    at javafx.beans.property.ObjectPropertyBase.markInvalid(ObjectPropertyBase.java:111)
    at javafx.beans.property.ObjectPropertyBase.set(ObjectPropertyBase.java:146)
    at javafx.scene.Scene$KeyHandler.setFocusOwner(Scene.java:3924)
    at javafx.scene.Scene$KeyHandler.requestFocus(Scene.java:3971)
    at javafx.scene.Scene$KeyHandler.access$1900(Scene.java:3910)
    at javafx.scene.Scene.requestFocus(Scene.java:2044)
    at javafx.scene.Node.requestFocus(Node.java:7879)
    at com.sun.javafx.scene.control.behavior.ChoiceBoxBehavior.mousePressed(ChoiceBoxBehavior.java:120)
    at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:95)
    at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:89)
    at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
    at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
    at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
    at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
    at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
    at javafx.event.Event.fireEvent(Event.java:198)
    at javafx.scene.Scene$MouseHandler.process(Scene.java:3757)
    at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3485)
    at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762)
    at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2494)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:394)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$358(GlassViewEventHandler.java:432)
    at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:431)
    at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
    at com.sun.glass.ui.View.notifyMouse(View.java:937)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$152(WinApplication.java:177)
    at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71)
    at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
    at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1771)
    ... 71 more
Caused by: java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Integer
    at application.controllers.ControllerCalendar.handleYear(ControllerCalendar.java:34)
    ... 81 more