Java 当我尝试将JPA用于本地数据存储时，EclipseRCP引发异常

我的RCP应用程序中有以下代码：

EntityManagerFactory emf = Persistence.createEntityManagerFactory("todos");
EntityManager em = emf.createEntityManager();
Query q = em.createQuery("select t from Todo t");
@SuppressWarnings("unchecked")
List<Todo> todos = (List<Todo>)q.getResultList();

根本没有创建数据库文件。你知道这是什么原因吗

添加：下面是完整的堆栈跟踪：

Local Exception Stack: 
Exception [EclipseLink-30009] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.PersistenceUnitLoadingException
Exception Description: An exception was thrown while trying to load persistence unit at url: bundleresource://51.fwk998462082:10
Internal Exception: Exception [EclipseLink-30004] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.PersistenceUnitLoadingException
Exception Description: An exception was thrown while processing persistence.xml from URL: bundleresource://51.fwk998462082:10
Internal Exception: 
(1. URI was not reported to parser for entity [document])
at org.eclipse.persistence.exceptions.PersistenceUnitLoadingException.exceptionLoadingFromUrl(PersistenceUnitLoadingException.java:100)
at org.eclipse.persistence.internal.jpa.deployment.PersistenceUnitProcessor.processPersistenceArchive(PersistenceUnitProcessor.java:538)
at org.eclipse.persistence.internal.jpa.deployment.PersistenceUnitProcessor.getPersistenceUnits(PersistenceUnitProcessor.java:444)
at org.eclipse.persistence.internal.jpa.deployment.JPAInitializer.findPersistenceUnitInfoInArchive(JPAInitializer.java:172)
at org.eclipse.persistence.internal.jpa.deployment.JPAInitializer.findPersistenceUnitInfoInArchives(JPAInitializer.java:154)
at org.eclipse.persistence.internal.jpa.deployment.JPAInitializer.findPersistenceUnitInfo(JPAInitializer.java:135)
at org.eclipse.persistence.jpa.PersistenceProvider.createEntityManagerFactory(PersistenceProvider.java:73)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:83)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:60)
at com.diligentgaming.dcm.workstation.plugins.core.dashboard.DashboardView.createPartControl(DashboardView.java:64)
at org.eclipse.ui.internal.ViewReference.createPartHelper(ViewReference.java:375)
at org.eclipse.ui.internal.ViewReference.createPart(ViewReference.java:229)
at org.eclipse.ui.internal.WorkbenchPartReference.getPart(WorkbenchPartReference.java:595)
at org.eclipse.ui.internal.PartPane.setVisible(PartPane.java:313)
at org.eclipse.ui.internal.ViewPane.setVisible(ViewPane.java:534)
at org.eclipse.ui.internal.presentations.PresentablePart.setVisible(PresentablePart.java:180)
at org.eclipse.ui.internal.presentations.util.PresentablePartFolder.select(PresentablePartFolder.java:270)
at org.eclipse.ui.internal.presentations.util.LeftToRightTabOrder.select(LeftToRightTabOrder.java:65)
at org.eclipse.ui.internal.presentations.util.TabbedStackPresentation.selectPart(TabbedStackPresentation.java:473)
at org.eclipse.ui.internal.PartStack.refreshPresentationSelection(PartStack.java:1245)
at org.eclipse.ui.internal.PartStack.setSelection(PartStack.java:1198)
at org.eclipse.ui.internal.PartStack.showPart(PartStack.java:1597)
at org.eclipse.ui.internal.PartStack.createControl(PartStack.java:643)
at org.eclipse.ui.internal.PartStack.createControl(PartStack.java:570)
at org.eclipse.ui.internal.PartSashContainer.createControl(PartSashContainer.java:568)
at org.eclipse.ui.internal.PerspectiveHelper.activate(PerspectiveHelper.java:272)
at org.eclipse.ui.internal.Perspective.onActivate(Perspective.java:981)
at org.eclipse.ui.internal.WorkbenchPage.onActivate(WorkbenchPage.java:2714)
at org.eclipse.ui.internal.WorkbenchWindow$28.run(WorkbenchWindow.java:3030)
at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70)
at org.eclipse.ui.internal.WorkbenchWindow.setActivePage(WorkbenchWindow.java:3011)
at org.eclipse.ui.internal.WorkbenchWindow.busyOpenPage(WorkbenchWindow.java:799)
at org.eclipse.ui.internal.Workbench$23.runWithException(Workbench.java:1229)
at org.eclipse.ui.internal.StartupThreading$StartupRunnable.run(StartupThreading.java:31)
at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:135)
at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:3938)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3615)
at org.eclipse.ui.application.WorkbenchAdvisor.openWindows(WorkbenchAdvisor.java:803)
at org.eclipse.ui.internal.Workbench$33.runWithException(Workbench.java:1600)
at org.eclipse.ui.internal.StartupThreading$StartupRunnable.run(StartupThreading.java:31)
at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:135)
at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:3938)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3615)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2609)
at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2499)
at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:679)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:668)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at com.diligentgaming.dcm.workstation.plugins.core.Application.start(Application.java:20)
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:344)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:622)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:577)
at org.eclipse.equinox.launcher.Main.run(Main.java:1410)
at org.eclipse.equinox.launcher.Main.main(Main.java:1386)
Caused by: Exception [EclipseLink-30004] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.PersistenceUnitLoadingException
Exception Description: An exception was thrown while processing persistence.xml from URL: bundleresource://51.fwk998462082:10
Internal Exception: 
(1. URI was not reported to parser for entity [document])
at org.eclipse.persistence.exceptions.PersistenceUnitLoadingException.exceptionProcessingPersistenceXML(PersistenceUnitLoadingException.java:118)
at org.eclipse.persistence.internal.jpa.deployment.PersistenceUnitProcessor.processPersistenceXML(PersistenceUnitProcessor.java:587)
at org.eclipse.persistence.internal.jpa.deployment.PersistenceUnitProcessor.processPersistenceArchive(PersistenceUnitProcessor.java:536)
... 63 more
Caused by: 
(1. URI was not reported to parser for entity [document])
at org.eclipse.persistence.internal.jpa.deployment.xml.parser.XMLExceptionHandler.error(XMLExceptionHandler.java:28)
at org.eclipse.persistence.internal.jpa.deployment.xml.parser.XMLExceptionHandler.warning(XMLExceptionHandler.java:23)
at gnu.xml.aelfred2.SAXDriver.warn(SAXDriver.java:935)
at gnu.xml.aelfred2.SAXDriver.startExternalEntity(SAXDriver.java:631)
at gnu.xml.aelfred2.XmlParser.pushURL(XmlParser.java:3358)
at gnu.xml.aelfred2.XmlParser.doParse(XmlParser.java:159)
at gnu.xml.aelfred2.SAXDriver.parse(SAXDriver.java:320)
at gnu.xml.aelfred2.XmlReader.parse(XmlReader.java:294)
at org.eclipse.persistence.internal.jpa.deployment.PersistenceUnitProcessor.processPersistenceXML(PersistenceUnitProcessor.java:577)
... 64 more</code>

---

答案是从类路径中删除gnujaxp.jar，之后一切似乎都正常。

你能包括完整的堆栈跟踪吗，你在非OSGi环境中尝试过相同的持久化单元吗？嗨，James，我没有在非OSGi环境中尝试过，这是完整的堆栈跟踪。看起来我的persistence.xml在某种程度上是错误的，但我不知道怎么回事，我觉得它还可以。

Could not create the view: 
Exception Description: An exception was thrown while searching for persistence archives with ClassLoader: org.eclipse.core.runtime.internal.adaptor.ContextFinder@4b51ac10
Internal Exception: Exception [EclipseLink-30009] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.PersistenceUnitLoadingException
Exception Description: An exception was thrown while trying to load persistence unit at url: bundleresource://51.fwk2013125681:10
Internal Exception: Exception [EclipseLink-30004] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.PersistenceUnitLoadingException
Exception Description: An exception was thrown while processing persistence.xml from URL: bundleresource://51.fwk2013125681:10
Internal Exception: 
(1. URI was not reported to parser for entity [document])

Local Exception Stack: 
Exception [EclipseLink-30009] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.PersistenceUnitLoadingException
Exception Description: An exception was thrown while trying to load persistence unit at url: bundleresource://51.fwk998462082:10
Internal Exception: Exception [EclipseLink-30004] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.PersistenceUnitLoadingException
Exception Description: An exception was thrown while processing persistence.xml from URL: bundleresource://51.fwk998462082:10
Internal Exception: 
(1. URI was not reported to parser for entity [document])
at org.eclipse.persistence.exceptions.PersistenceUnitLoadingException.exceptionLoadingFromUrl(PersistenceUnitLoadingException.java:100)
at org.eclipse.persistence.internal.jpa.deployment.PersistenceUnitProcessor.processPersistenceArchive(PersistenceUnitProcessor.java:538)
at org.eclipse.persistence.internal.jpa.deployment.PersistenceUnitProcessor.getPersistenceUnits(PersistenceUnitProcessor.java:444)
at org.eclipse.persistence.internal.jpa.deployment.JPAInitializer.findPersistenceUnitInfoInArchive(JPAInitializer.java:172)
at org.eclipse.persistence.internal.jpa.deployment.JPAInitializer.findPersistenceUnitInfoInArchives(JPAInitializer.java:154)
at org.eclipse.persistence.internal.jpa.deployment.JPAInitializer.findPersistenceUnitInfo(JPAInitializer.java:135)
at org.eclipse.persistence.jpa.PersistenceProvider.createEntityManagerFactory(PersistenceProvider.java:73)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:83)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:60)
at com.diligentgaming.dcm.workstation.plugins.core.dashboard.DashboardView.createPartControl(DashboardView.java:64)
at org.eclipse.ui.internal.ViewReference.createPartHelper(ViewReference.java:375)
at org.eclipse.ui.internal.ViewReference.createPart(ViewReference.java:229)
at org.eclipse.ui.internal.WorkbenchPartReference.getPart(WorkbenchPartReference.java:595)
at org.eclipse.ui.internal.PartPane.setVisible(PartPane.java:313)
at org.eclipse.ui.internal.ViewPane.setVisible(ViewPane.java:534)
at org.eclipse.ui.internal.presentations.PresentablePart.setVisible(PresentablePart.java:180)
at org.eclipse.ui.internal.presentations.util.PresentablePartFolder.select(PresentablePartFolder.java:270)
at org.eclipse.ui.internal.presentations.util.LeftToRightTabOrder.select(LeftToRightTabOrder.java:65)
at org.eclipse.ui.internal.presentations.util.TabbedStackPresentation.selectPart(TabbedStackPresentation.java:473)
at org.eclipse.ui.internal.PartStack.refreshPresentationSelection(PartStack.java:1245)
at org.eclipse.ui.internal.PartStack.setSelection(PartStack.java:1198)
at org.eclipse.ui.internal.PartStack.showPart(PartStack.java:1597)
at org.eclipse.ui.internal.PartStack.createControl(PartStack.java:643)
at org.eclipse.ui.internal.PartStack.createControl(PartStack.java:570)
at org.eclipse.ui.internal.PartSashContainer.createControl(PartSashContainer.java:568)
at org.eclipse.ui.internal.PerspectiveHelper.activate(PerspectiveHelper.java:272)
at org.eclipse.ui.internal.Perspective.onActivate(Perspective.java:981)
at org.eclipse.ui.internal.WorkbenchPage.onActivate(WorkbenchPage.java:2714)
at org.eclipse.ui.internal.WorkbenchWindow$28.run(WorkbenchWindow.java:3030)
at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70)
at org.eclipse.ui.internal.WorkbenchWindow.setActivePage(WorkbenchWindow.java:3011)
at org.eclipse.ui.internal.WorkbenchWindow.busyOpenPage(WorkbenchWindow.java:799)
at org.eclipse.ui.internal.Workbench$23.runWithException(Workbench.java:1229)
at org.eclipse.ui.internal.StartupThreading$StartupRunnable.run(StartupThreading.java:31)
at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:135)
at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:3938)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3615)
at org.eclipse.ui.application.WorkbenchAdvisor.openWindows(WorkbenchAdvisor.java:803)
at org.eclipse.ui.internal.Workbench$33.runWithException(Workbench.java:1600)
at org.eclipse.ui.internal.StartupThreading$StartupRunnable.run(StartupThreading.java:31)
at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:135)
at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:3938)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3615)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2609)
at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2499)
at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:679)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:668)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at com.diligentgaming.dcm.workstation.plugins.core.Application.start(Application.java:20)
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:344)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:622)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:577)
at org.eclipse.equinox.launcher.Main.run(Main.java:1410)
at org.eclipse.equinox.launcher.Main.main(Main.java:1386)
Caused by: Exception [EclipseLink-30004] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.PersistenceUnitLoadingException
Exception Description: An exception was thrown while processing persistence.xml from URL: bundleresource://51.fwk998462082:10
Internal Exception: 
(1. URI was not reported to parser for entity [document])
at org.eclipse.persistence.exceptions.PersistenceUnitLoadingException.exceptionProcessingPersistenceXML(PersistenceUnitLoadingException.java:118)
at org.eclipse.persistence.internal.jpa.deployment.PersistenceUnitProcessor.processPersistenceXML(PersistenceUnitProcessor.java:587)
at org.eclipse.persistence.internal.jpa.deployment.PersistenceUnitProcessor.processPersistenceArchive(PersistenceUnitProcessor.java:536)
... 63 more
Caused by: 
(1. URI was not reported to parser for entity [document])
at org.eclipse.persistence.internal.jpa.deployment.xml.parser.XMLExceptionHandler.error(XMLExceptionHandler.java:28)
at org.eclipse.persistence.internal.jpa.deployment.xml.parser.XMLExceptionHandler.warning(XMLExceptionHandler.java:23)
at gnu.xml.aelfred2.SAXDriver.warn(SAXDriver.java:935)
at gnu.xml.aelfred2.SAXDriver.startExternalEntity(SAXDriver.java:631)
at gnu.xml.aelfred2.XmlParser.pushURL(XmlParser.java:3358)
at gnu.xml.aelfred2.XmlParser.doParse(XmlParser.java:159)
at gnu.xml.aelfred2.SAXDriver.parse(SAXDriver.java:320)
at gnu.xml.aelfred2.XmlReader.parse(XmlReader.java:294)
at org.eclipse.persistence.internal.jpa.deployment.PersistenceUnitProcessor.processPersistenceXML(PersistenceUnitProcessor.java:577)
... 64 more</code>