【发布时间】：2025-12-27 21:20:12
【问题描述】：
我正在编写一个 JavaFX 应用程序，其中 FXController 是不同类的观察者。我需要获取观察者最后一次收到更新通知的时间。问题是我正在尝试使用LocalDateTime 和LocalDateTime 一起使用java8 时间API，并且每次我调用LocalDateTime.now() 它都会给我一个NullPointerException 指向一些不存在的tzbd 文件。
但是，如果我只是打开一个控制台项目并在那里运行代码，LocalDateTime.now() 可以在我的系统上完美运行。
那么 JavaFX 有问题吗？有什么解决方法吗？
抛出异常的代码：
public void getTimeStamp() {
LocalDateTime c = LocalDateTime.now();
System.out.println("Grand Total has been updated ... @ " + c);
}
@Override
public void update(Observable o, Object arg) {
grandTotal.setText(
Integer.toString(
controller.getReg().getGrandTotal()
)
);
System.out.println("Update() called @ ");
getTimeStamp();
}
这里是完整的异常堆栈跟踪：
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:8413)
at javafx.scene.control.Button.fire(Button.java:185)
at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:182)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:96)
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$MouseEventNotification.run(GlassViewEventHandler.java:381)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$354(GlassViewEventHandler.java:417)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:416)
at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
at com.sun.glass.ui.View.notifyMouse(View.java:937)
at com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method)
at com.sun.glass.ui.gtk.GtkApplication.lambda$null$49(GtkApplication.java:139)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71)
at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1771)
... 48 more
Caused by: java.lang.Error: java.io.FileNotFoundException: null/lib/tzdb.dat (No such file or directory)
at sun.util.calendar.ZoneInfoFile$1.run(ZoneInfoFile.java:261)
at java.security.AccessController.doPrivileged(Native Method)
at sun.util.calendar.ZoneInfoFile.<clinit>(ZoneInfoFile.java:251)
at sun.util.calendar.ZoneInfo.getTimeZone(ZoneInfo.java:589)
at java.util.TimeZone.getTimeZone(TimeZone.java:560)
at java.util.TimeZone.setDefaultZone(TimeZone.java:666)
at java.util.TimeZone.getDefaultRef(TimeZone.java:636)
at java.util.TimeZone.getDefault(TimeZone.java:625)
at java.time.ZoneId.systemDefault(ZoneId.java:274)
at java.time.Clock.systemDefaultZone(Clock.java:178)
at java.time.LocalDateTime.now(LocalDateTime.java:180)
at assignment.notifiers.BeepMaker.playBeep(BeepMaker.java:11)
at assignment.controller.RegistrationFxController.calculateDiscount(RegistrationFxController.java:178)
... 58 more
Caused by: java.io.FileNotFoundException: null/lib/tzdb.dat (No such file or directory)
at java.io.FileInputStream.open0(Native Method)
at java.io.FileInputStream.open(FileInputStream.java:195)
at java.io.FileInputStream.<init>(FileInputStream.java:138)
at sun.util.calendar.ZoneInfoFile$1.run(ZoneInfoFile.java:255)
... 70 more
Process finished with exit code 0
【问题讨论】：
-
Caused by: java.io.FileNotFoundException: null/lib/tzdb.dat (No such file or directory)- 您在哪个 JRE 版本上运行您的代码？当我查看 ZoneInfoFile 的源代码时，它与您的堆栈跟踪不匹配。 -
JRE 8 u121。
-
我也有这个问题：很好，这个文件在 OpenSUSE 上找不到，但我在 macOS 上试过了，同样的事情。您是否建议在 OpenSUSE 以外的操作系统上完全重新编译这些类？
标签： java javafx observer-pattern