按照here的说明（特别是任务3和4），我正在从Toplink 10g迁移到本机Eclipselink v2.6.4。一切都编译好，但当我尝试运行我的应用程序时，我得到以下错误。
我尝试使用旧的映射文件（仍然兼容）以及通过导入旧的Toplink工作台项目从Eclipselink工作台生成的新映射文件。
请注意，我只是从Toplink迁移到本机Eclispelink。没有涉及JPA。
关于什么错误的任何想法？似乎它试图不正确地使用String而不是我的实际类，但不确定。
此外，我的应用程序从未有过persistence.xml文件。我现在需要一个吗？
2017-02-20 14:55:52 ERROR - Presentation - Local Exception Stack:
Exception [EclipseLink-3002] (Eclipse Persistence Services - 2.6.4.v20160829-44060b6): org.eclipse.persistence.exceptions.ConversionException
Exception Description: The object [ca.ncams.wisor.refdata.AccessTandem], of class [class java.lang.String], from mapping [org.eclipse.persistence.oxm.mappings.XMLDirectMapping[javaClass-->class/text()]] with descriptor [XMLDescriptor(org.eclipse.persistence.descriptors.ClassDescriptor --> [DatabaseTable(class-mapping-descriptor)])], could not be converted to [class java.lang.Class].
Internal Exception: java.lang.ClassNotFoundException: ca.ncams.wisor.refdata.AccessTandem
at org.eclipse.persistence.exceptions.ConversionException.couldNotBeConvertedToClass(ConversionException.java:98)
at org.eclipse.persistence.internal.helper.ConversionManager.convertObjectToClass(ConversionManager.java:451)
at org.eclipse.persistence.internal.helper.ConversionManager.convertObject(ConversionManager.java:146)
at org.eclipse.persistence.internal.oxm.XMLConversionManager.convertObject(XMLConversionManager.java:197)
at org.eclipse.persistence.internal.databaseaccess.DatasourcePlatform.convertObject(DatasourcePlatform.java:179)
at org.eclipse.persistence.oxm.mappings.XMLDirectMapping.getAttributeValue(XMLDirectMapping.java:301)
at org.eclipse.persistence.oxm.mappings.XMLDirectMapping.valueFromRow(XMLDirectMapping.java:364)
at org.eclipse.persistence.mappings.DatabaseMapping.readFromRowIntoObject(DatabaseMapping.java:1539)
at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildAttributesIntoObject(ObjectBuilder.java:462)
at org.eclipse.persistence.internal.oxm.XMLObjectBuilder.buildAttributesIntoObject(XMLObjectBuilder.java:378)
at org.eclipse.persistence.internal.oxm.XMLObjectBuilder.buildObject(XMLObjectBuilder.java:291)
at org.eclipse.persistence.oxm.mappings.XMLCompositeCollectionMapping.buildCompositeObject(XMLCompositeCollectionMapping.java:380)
at org.eclipse.persistence.oxm.mappings.XMLCompositeCollectionMapping.buildObjectFromNestedRow(XMLCompositeCollectionMapping.java:587)
at org.eclipse.persistence.oxm.mappings.XMLCompositeCollectionMapping.valueFromRow(XMLCompositeCollectionMapping.java:511)
at org.eclipse.persistence.mappings.DatabaseMapping.readFromRowIntoObject(DatabaseMapping.java:1539)
at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildAttributesIntoObject(ObjectBuilder.java:462)
at org.eclipse.persistence.internal.oxm.XMLObjectBuilder.buildAttributesIntoObject(XMLObjectBuilder.java:378)
at org.eclipse.persistence.internal.oxm.XMLObjectBuilder.buildObject(XMLObjectBuilder.java:291)
at org.eclipse.persistence.internal.oxm.record.DOMUnmarshaller.xmlToObject(DOMUnmarshaller.java:469)
at org.eclipse.persistence.internal.oxm.record.DOMUnmarshaller.unmarshal(DOMUnmarshaller.java:267)
at org.eclipse.persistence.internal.oxm.record.DOMUnmarshaller.unmarshal(DOMUnmarshaller.java:246)
at org.eclipse.persistence.internal.oxm.XMLUnmarshaller.unmarshal(XMLUnmarshaller.java:530)
at org.eclipse.persistence.sessions.factories.XMLProjectReader.readObjectPersistenceRuntimeFormat(XMLProjectReader.java:293)
at org.eclipse.persistence.sessions.factories.XMLProjectReader.read(XMLProjectReader.java:186)
at org.eclipse.persistence.sessions.factories.XMLProjectReader.read(XMLProjectReader.java:242)
at org.eclipse.persistence.sessions.factories.XMLProjectReader.read(XMLProjectReader.java:100)
at ca.ncams.wisor.persistence.toplink.PersistenceManager.initializeTopLink(PersistenceManager.java:491)
at ca.ncams.wisor.persistence.toplink.PersistenceManager.<init>(PersistenceManager.java:83)
at ca.ncams.wisor.persistence.toplink.PersistenceManager.getInstance(PersistenceManager.java:96)
at ca.ncams.wisor.persistence.toplink.AutoRollbackFilter.doFilter(AutoRollbackFilter.java:57)
at ca.ncams.wisor.filter.FilterChainImpl.doFilter(FilterChainImpl.java:124)
at ca.ncams.wisor.presentation.filters.CatchAllFilter.doFilter(CatchAllFilter.java:60)
at ca.ncams.wisor.filter.FilterChainImpl.doFilter(FilterChainImpl.java:124)
at ca.ncams.wisor.presentation.filters.NoCacheFilter.doFilter(NoCacheFilter.java:47)
at ca.ncams.wisor.filter.FilterChainImpl.doFilter(FilterChainImpl.java:124)
at ca.ncams.wisor.filter.FilterJspBase.service(FilterJspBase.java:111)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:286)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:260)
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:137)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:350)
at weblogic.servlet.internal.ServletStubImpl.onAddToMapException(ServletStubImpl.java:489)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:376)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:247)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.wrapRun(WebAppServletContext.java:3679)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.__run(WebAppServletContext.java:3649)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java)
at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:326)
at weblogic.security.service.SecurityManager.runAsForUserCode(SecurityManager.java:197)
at weblogic.servlet.provider.WlsSecurityProvider.runAsForUserCode(WlsSecurityProvider.java:203)
at weblogic.servlet.provider.WlsSubjectHandle.run(WlsSubjectHandle.java:71)
at weblogic.servlet.internal.WebAppServletContext.doSecuredExecute(WebAppServletContext.java:2433)
at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2281)
at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2259)
at weblogic.servlet.internal.ServletRequestImpl.runInternal(ServletRequestImpl.java:1691)
at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1651)
at weblogic.servlet.provider.ContainerSupportProviderImpl$WlsRequestExecutor.run(ContainerSupportProviderImpl.java:270)
at weblogic.invocation.ComponentInvocationContextManager._runAs(ComponentInvocationContextManager.java:348)
at weblogic.invocation.ComponentInvocationContextManager.runAs(ComponentInvocationContextManager.java:333)
at weblogic.work.LivePartitionUtility.doRunWorkUnderContext(LivePartitionUtility.java:54)
at weblogic.work.PartitionUtility.runWorkUnderContext(PartitionUtility.java:41)
at weblogic.work.SelfTuningWorkManagerImpl.runWorkUnderContext(SelfTuningWorkManagerImpl.java:640)
at weblogic.work.ExecuteThread.execute(ExecuteThread.java:406)
at weblogic.work.ExecuteThread.run(ExecuteThread.java:346)
Caused by: java.lang.ClassNotFoundException: ca.ncams.wisor.refdata.AccessTandem
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:348)
at org.eclipse.persistence.internal.helper.ConversionManager.convertObjectToClass(ConversionManager.java:448)
... 61 more
答案 0 :(得分：0)
这是我最终做的事情：
<wls:container-descriptor> <wls:prefer-application-packages> <wls:package-name>org.eclipse.persistence</wls:package-name> </wls:prefer-application-packages> </wls:container-descriptor>
现在Eclipselink找到了我的课程并启动了。
请注意，我的代码只是传递给映射文件，而不是传递给XMLProjectReader.read();的类加载器，所以我想使用的是默认的类加载器。
如果有人知道如何传入类加载器，我仍然很想知道（我从哪里得到它？）。