Java 在Eclipse4中将值传递给其他视图时出错

我正在使用IEventBroker将事件同步发送到其他视图

@Inject
private IEventBroker eventBroker; 

发送方部件具有以下代码：

Map<String,List<TreeMap<Timestamp, Long>>> StatisticValue = new HashMap<String,List<TreeMap<Timestamp, Long>>>();
//some code to add values in statisticValue
eventBroker.send("value", StatisticValue);

---

我很困惑为什么我会犯这个错误。我已经检查了发送方中StatisticValue的大小（size=2）。但它显示了一些空指针异常。有人能帮我吗？

由于

entriesForTs

为空，因此在

getEvent

方法中报告了一个

NullPointerException

异常

处理代码的

@UIEventTopic

似乎在第一次使用事件处理程序时使用空值调用了它一次（然后使用正确的值再次调用）。所以只需在

getEvent

中检查null

更新：

您可以尝试使用

org.osgi.service.event.event

作为

getEvent

参数的类型，以防解析参数类型时出现问题：

public void getEvent(@UIEventTopic("value") Event event)
{
  data = event.getProperty(IEventBroker.DATA);

如果

@UIEventTopic

拒绝工作，您也可以尝试

IEventBroker.subscribe

更新2：

---

事件代理

send

（和

post

）方法专门处理

Map

，并假定它是包含要发送的值的映射。因此，它将在地图中查找

IEventBroker.DATA

键。最好将地图包装在容器类中。

我添加了一个检查（entriesForTs！=null）System.out.println（“value”+entriesForTs.size（））；但是，该值不会被打印出来。它没有进入if条件内部。添加了一些东西来尝试使用@UIEventTopic我可以传递字符串值，但只有当我尝试传递

HashMap

数据类型时，我才收到空值。请记住，Map在

send

调用中被特别处理，请参阅更新。

 Exception while dispatching event org.osgi.service.event.Event [topic=value] to handler org.eclipse.e4.ui.internal.di.UIEventObjectSupplier$UIEventHandler@6d79dea2
!STACK 0
org.eclipse.e4.core.di.InjectionException: java.lang.NullPointerException
    at org.eclipse.e4.core.internal.di.MethodRequestor.execute(MethodRequestor.java:63)
    at org.eclipse.e4.ui.internal.di.UIEventObjectSupplier$UIEventHandler$1.run(UIEventObjectSupplier.java:49)
    at org.eclipse.swt.widgets.Synchronizer.syncExec(Synchronizer.java:180)
    at org.eclipse.swt.widgets.Display.syncExec(Display.java:4688)
    at org.eclipse.e4.ui.internal.workbench.swt.E4Application$1.syncExec(E4Application.java:205)
    at org.eclipse.e4.ui.internal.di.UIEventObjectSupplier$UIEventHandler.handleEvent(UIEventObjectSupplier.java:47)
    at org.eclipse.equinox.internal.event.EventHandlerWrapper.handleEvent(EventHandlerWrapper.java:197)
    at org.eclipse.equinox.internal.event.EventHandlerTracker.dispatchEvent(EventHandlerTracker.java:197)
    at org.eclipse.equinox.internal.event.EventHandlerTracker.dispatchEvent(EventHandlerTracker.java:1)
    at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:230)
    at org.eclipse.osgi.framework.eventmgr.ListenerQueue.dispatchEventSynchronous(ListenerQueue.java:148)
    at org.eclipse.equinox.internal.event.EventAdminImpl.dispatchEvent(EventAdminImpl.java:135)
    at org.eclipse.equinox.internal.event.EventAdminImpl.sendEvent(EventAdminImpl.java:78)
    at org.eclipse.equinox.internal.event.EventComponent.sendEvent(EventComponent.java:39)
    at org.eclipse.e4.ui.services.internal.events.EventBroker.send(EventBroker.java:80)
    at com.xyz.abc.project.parts.StatisticsPart.processFiles(StatisticsPart.java:270)
    at com.xyz.abc.project.parts.StatisticsPart$5.selectionChanged(StatisticsPart.java:205)
    at org.eclipse.jface.viewers.Viewer$2.run(Viewer.java:164)
    at org.eclipse.jface.util.SafeRunnable$1.run(SafeRunnable.java:128)
    at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:175)
    at org.eclipse.jface.viewers.Viewer.fireSelectionChanged(Viewer.java:162)
    at org.eclipse.jface.viewers.StructuredViewer.updateSelection(StructuredViewer.java:2188)
    at org.eclipse.jface.viewers.StructuredViewer.handleSelect(StructuredViewer.java:1211)
    at org.eclipse.jface.viewers.StructuredViewer$4.widgetSelected(StructuredViewer.java:1241)
    at org.eclipse.jface.util.OpenStrategy.fireSelectionEvent(OpenStrategy.java:239)
    at org.eclipse.jface.util.OpenStrategy.access$4(OpenStrategy.java:233)
    at org.eclipse.jface.util.OpenStrategy$1.handleEvent(OpenStrategy.java:403)
    at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1057)
    at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4170)
    at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3759)
    at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$9.run(PartRenderingEngine.java:1113)
    at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
    at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:997)
    at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:138)
    at org.eclipse.e4.ui.internal.workbench.swt.E4Application.start(E4Application.java:162)
    at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
    at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
    at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:354)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:181)
    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 org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:636)
    at org.eclipse.equinox.launcher.Main.basicRun(Main.java:591)
    at org.eclipse.equinox.launcher.Main.run(Main.java:1450)
    at org.eclipse.equinox.launcher.Main.main(Main.java:1426)
Caused by: java.lang.NullPointerException
    at com.xyz.abc.project.parts.showGraph.getEvent(showGraph.java:109)
    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 org.eclipse.e4.core.internal.di.MethodRequestor.execute(MethodRequestor.java:56)
    ... 48 more

public void getEvent(@UIEventTopic("value") Event event)
{
  data = event.getProperty(IEventBroker.DATA);