java.sql.date 的吸气剂和吸气剂

Question

我想 get/set 日期对象的年、月和日，但 eclipse 说它已被弃用，我在执行代码时得到 NullPointerException（老实说我不是确定我是否因此而得到异常，但它看起来是那样的）。

这是我想做的事的一个例子：

public TSTLocalDate dateToTSTLocalDate(Date date) {     

    this.calenderDate.year = date.getYear();            
    this.calenderDate.month = date.getMonth();          
    this.calenderDate.day = date.getDay();

    return this.calenderDate;
}

最终，我的目标是将 Date 转换为我自己创建的 Datetype。

还有其他方法可以get/set约会吗？

编辑：这是一个例外，但它指的是代码中的其他一些东西，我不能 post 这里的所有内容：

Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
at com.ferdec.tst.tstgui.domain.TSTHoliday.dateToTSTLocalDate(TSTHoliday.java:145)
at com.ferdec.tst.tstgui.domain.TSTHoliday.<init>(TSTHoliday.java:42)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at com.ferdec.tst.tstgui.view.StaticDataHandlerFactory.handle(StaticDataHandlerFactory.java:909)
at com.ferdec.tst.tstgui.view.StaticDataHandlerFactory.handle(StaticDataHandlerFactory.java:1)
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.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.handle(BehaviorSkinBase.java:96)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase.handle(BehaviorSkinBase.java:89)
at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3757)
at javafx.scene.Scene$MouseHandler.access00(Scene.java:3485)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762)
at javafx.scene.Scene$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$handleMouseEvent3(GlassViewEventHandler.java:432)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:431)
at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
at com.sun.glass.ui.View.notifyMouse(View.java:937)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null7(WinApplication.java:177)
at java.lang.Thread.run(Unknown Source)

Answer 1

在异常的第 2 行，它可能发生在确切的行：

TSTHoliday.dateToTSTLocalDate(TSTHoliday.java:145)

呼叫者

TSTHoliday.java:42

检查传递给这个方法的 date 对象是否为 null，像这样：

TSTLocalDate tSTLocalDate;
if(date != null) {
    tSTLocalDate = dateToTSTLocalDate(date);
}

并且在该方法中，您可以添加空值检查：

public TSTLocalDate dateToTSTLocalDate(Date date) {     

    if(date == null) {
        Log.d("TAGLOG", "Error date null in dateToTSTLocalDate");
    }
    else {
        this.calenderDate.year = date.getYear();            
        this.calenderDate.month = date.getMonth();          
        this.calenderDate.day = date.getDay();
    }

    return this.calenderDate;
}

Answer 2

`Objects.requireNonNull`

正如其他人指出的那样，您应该 check that incoming argument 不为空。

public TSTLocalDate dateToTSTLocalDate(Date date) {     
    Objects.requireNonNull( date , "Opps, received a NULL rather than a Date object. Message # e99b92a3-da0b-419b-9f93-8cfee36a757b." ) ;
…

您还有其他问题。

时区

Date 表示 UTC 中的一个时刻。确定日期需要时区。对于任何给定时刻，日期在全球范围内因地区而异。

但是你的代码忽略了这个关键的时区问题。当您忽略提供时区时，Calendar class（实际上是 GregorianCalendar）隐式使用 JVM 当前的默认时区。所以你的结果可能会有所不同。最好始终明确指定您的 desired/expected 时区。

java.time

另一个问题：您使用的日期时间 classes 多年前被现代 java.time classes 取代.

将您的 java.util.Date 转换为 Instant，这两个 class 代表 UTC 中的一个时刻。

Instant instant = myJavaUtilDate.toInstant() ;

指定您的 desired/expected 区域。

ZoneId z = ZoneId.of( "America/Montreal" ) ;
ZonedDateTime zdt = instant.atZone( z ) ;

提取只有日期的部分，没有时间，也没有时区。

LocalDate ld = zdt.toLocalDate() ;

您可以查询 LocalDate 的年月日。

您可以使用 DateTimeFormatter 生成表示 LocalDate 值的各种格式的字符串。

java.sql.date 的吸气剂和吸气剂

Getters and setters for java.sql.date

java

date

deprecated

getter-setter

`Objects.requireNonNull`

时区

java.time