如何在GAE上为grails应用程序设置一对多单向映射？

Question

我尝试使用JPA在Google App Engine（GAE）上的grails应用程序的一对多单向映射上执行测试。 我尝试定义的一对多单向映射是在User和Role类之间。 不幸的是，我被困住了。 奇怪的是，有没有开发人员能够使其成功工作。

以下是我的开发环境：

• Windows XP专业版
• App Engine SDK 1.2.2
• Grails 1.1.1
• 使用的插件：app引擎0.8.3，gorm-jpa 0.5

源代码位于：

• http://rapidshare.com/files/275369669/one2many.zip.html

完整的错误堆栈跟踪在这里：

 [java] Sep 4, 2009 2:08:42 AM com.google.apphosting.utils.jetty.JettyLogger warn
 [java] WARNING: Failed startup of context com.google.apphosting.utils.jetty.DevAppEngineWebAppContext@1ebd75b{/,C:\Documents and Settings\limcheekin\.grails\1.1.1\projects\one2many\stage}
 [java] org.springframework.beans.factory.access.BootstrapException: Error executing bootstraps; nested exception is org.codehaus.groovy.runtime.InvokerInvocationException: org.springframework.orm.jpa.JpaSystemException: Class "com.vobject.grailsfuse.User" has collection field "roles" and this has no mapping in the table for the element class "com.vobject.grailsfuse.Role"; nested exception is javax.persistence.PersistenceException: Class "com.vobject.grailsfuse.User" has collection field "roles" and this has no mapping in the table for the element class "com.vobject.grailsfuse.Role"
 [java]     at org.codehaus.groovy.grails.web.context.GrailsContextLoader.createWebApplicationContext(GrailsContextLoader.java:74)
 [java]     at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:199)
 [java]     at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:45)
 [java]     at org.mortbay.jetty.handler.ContextHandler.startContext(ContextHandler.java:530)
 [java]     at org.mortbay.jetty.servlet.Context.startContext(Context.java:135)
 [java]     at org.mortbay.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1218)
 [java]     at org.mortbay.jetty.handler.ContextHandler.doStart(ContextHandler.java:500)
 [java]     at org.mortbay.jetty.webapp.WebAppContext.doStart(WebAppContext.java:448)
 [java]     at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:40)
 [java]     at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:117)
 [java]     at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:40)
 [java]     at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:117)
 [java]     at org.mortbay.jetty.Server.doStart(Server.java:217)
 [java]     at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:40)
 [java]     at com.google.appengine.tools.development.JettyContainerService.startContainer(JettyContainerService.java:152)
 [java]     at com.google.appengine.tools.development.AbstractContainerService.startup(AbstractContainerService.java:116)
 [java]     at com.google.appengine.tools.development.DevAppServerImpl.start(DevAppServerImpl.java:218)
 [java]     at com.google.appengine.tools.development.DevAppServerMain$StartAction.apply(DevAppServerMain.java:162)
 [java]     at com.google.appengine.tools.util.Parser$ParseResult.applyArgs(Parser.java:48)
 [java]     at com.google.appengine.tools.development.DevAppServerMain.<init>(DevAppServerMain.java:113)
 [java]     at com.google.appengine.tools.development.DevAppServerMain.main(DevAppServerMain.java:89)
 [java] Caused by: org.codehaus.groovy.runtime.InvokerInvocationException: org.springframework.orm.jpa.JpaSystemException: Class "com.vobject.grailsfuse.User" has collection field "roles" and this has no mapping in the table for the element class "com.vobject.grailsfuse.Role"; nested exception is javax.persistence. PersistenceException: Class "com.vobject.grailsfuse.User" has collection field "roles" and this has no mapping in the table for the element class "com.vobject.grailsfuse.Role"
 [java]     ... 7 more
 [java] Caused by: org.springframework.orm.jpa.JpaSystemException: Class "com.vobject.grailsfuse.User" has collection field "roles" and this has no mapping in the table for the element class "com.vobject.grailsfuse.Role"; nested exception is javax.persistence.PersistenceException: Class "com.vobject.grailsfuse.User" has collection field "roles" and this has no mapping in the table for the element class "com.vobject.grailsfuse.Role"
 [java]     at org.grails.jpa.JpaPluginSupport$__clinit__closure3_closure6_closure11_closure38.doCall(JpaPluginSupport.groovy:452)
 [java]     at BootStrap$_closure1.doCall(BootStrap.groovy:13)
 [java]     ... 7 more
 [java] Caused by: javax.persistence.PersistenceException: Class "com.vobject.grailsfuse.User" has collection field "roles" and this has no mapping in the table for the element class "com.vobject.grailsfuse.Role"
 [java]     at org.datanucleus.jpa.NucleusJPAHelper.getJPAExceptionForNucleusException(NucleusJPAHelper.java:264)
 [java]     at org.datanucleus.jpa.EntityTransactionImpl.commit(EntityTransactionImpl.java:122)
 [java]     ... 9 more
 [java] Caused by: org.datanucleus.exceptions.NucleusUserException: Class "com.vobject.grailsfuse.User" has collection field "roles" and this has no mapping in the table for the element class "com.vobject.grailsfuse.Role"
 [java]     at org.datanucleus.store.mapped.scostore.FKSetStore.<init>(FKSetStore.java:184)
 [java]     at org.datanucleus.store.appengine.DatastoreFKSetStore.<init>(DatastoreFKSetStore.java:38)
 [java]     at org.datanucleus.store.appengine.DatastoreManager.newFKSetStore(DatastoreManager.java:353)
 [java]     at org.datanucleus.store.mapped.MappedStoreManager.getBackingStoreForCollection(MappedStoreManager.java:734)
 [java]     at org.datanucleus.store.mapped.MappedStoreManager.getBackingStoreForField(MappedStoreManager.java:646)
 [java]     at org.datanucleus.sco.backed.HashSet.<init>(HashSet.java:102)
 [java]     at org.datanucleus.util.ClassUtils.newInstance(ClassUtils.java:94)
 [java]     at org.datanucleus.sco.SCOUtils.newSCOInstance(SCOUtils.java:164)
 [java]     at org.datanucleus.state.JDOStateManagerImpl.wrapSCOField(JDOStateManagerImpl.java:3040)
 [java]     at org.datanucleus.store.fieldmanager.LoadFieldManager.internalFetchObjectField(LoadFieldManager.java:92)
 [java]     at org.datanucleus.store.fieldmanager.AbstractFetchFieldManager.fetchObjectField(AbstractFetchFieldManager.java:104)
 [java]     at org.datanucleus.state.AbstractStateManager.replacingObjectField(AbstractStateManager.java:1197)
 [java]     at com.vobject.grailsfuse.User.jdoReplaceField(User.groovy)
 [java]     at com.vobject.grailsfuse.User.jdoReplaceFields(User.groovy)
 [java]     at org.datanucleus.state.JDOStateManagerImpl.replaceFields(JDOStateManagerImpl.java:2772)
 [java]     at org.datanucleus.state.JDOStateManagerImpl.replaceFields(JDOStateManagerImpl.java:2791)
 [java]     at org.datanucleus.state.JDOStateManagerImpl.loadFieldsInFetchPlan(JDOStateManagerImpl.java:1610)
 [java]     at org.datanucleus.ObjectManagerImpl.performDetachAllOnCommitPreparation(ObjectManagerImpl.java:3192)
 [java]     at org.datanucleus.ObjectManagerImpl.preCommit(ObjectManagerImpl.java:2931)
 [java]     at org.datanucleus.TransactionImpl.internalPreCommit(TransactionImpl.java:369)
 [java]     at org.datanucleus.TransactionImpl.commit(TransactionImpl.java:256)
 [java]     at org.datanucleus.jpa.EntityTransactionImpl.commit(EntityTransactionImpl.java:104)
 [java]     ... 9 more
 [java] Sep 4, 2009 2:08:42 AM com.google.apphosting.utils.jetty.JettyLogger warn
 [java] WARNING: Nested in org.springframework.beans.factory.access.BootstrapException: Error executing bootstraps; nested exception is org.codehaus.groovy.runtime.InvokerInvocationException: org.springframework.orm.jpa.JpaSystemException: Class "com.vobject.grailsfuse.User" has collection field "roles" and this has no mapping in the table for the element class "com.vobject.grailsfuse.Role"; nested exception is javax.persistence.PersistenceException: Class "com.vobject.grailsfuse.User" has collection field "roles" and this has no mapping in the table for the element class "com.vobject.grailsfuse.Role":
 [java] Class "com.vobject.grailsfuse.User" has collection field "roles" and this has no mapping in the table for the element class "com.vobject.grailsfuse.Role"
 [java] org.datanucleus.exceptions.NucleusUserException: Class "com.vobject.grailsfuse.User" has collection field "roles" and this has no mapping in the table for the element class "com.vobject.grailsfuse.Role"
 [java]     at org.datanucleus.store.mapped.scostore.FKSetStore.<init>(FKSetStore.java:184)
 [java]     at org.datanucleus.store.appengine.DatastoreFKSetStore.<init>(DatastoreFKSetStore.java:38)
 [java]     at org.datanucleus.store.appengine.DatastoreManager.newFKSetStore(DatastoreManager.java:353)
 [java]     at org.datanucleus.store.mapped.MappedStoreManager.getBackingStoreForCollection(MappedStoreManager.java:734)
 [java]     at org.datanucleus.store.mapped.MappedStoreManager.getBackingStoreForField(MappedStoreManager.java:646)
 [java]     at org.datanucleus.sco.backed.HashSet.<init>(HashSet.java:102)
 [java]     at org.datanucleus.util.ClassUtils.newInstance(ClassUtils.java:94)
 [java]     at org.datanucleus.sco.SCOUtils.newSCOInstance(SCOUtils.java:164)
 [java]     at org.datanucleus.state.JDOStateManagerImpl.wrapSCOField(JDOStateManagerImpl.java:3040)
 [java]     at org.datanucleus.store.fieldmanager.LoadFieldManager.internalFetchObjectField(LoadFieldManager.java:92)
 [java]     at org.datanucleus.store.fieldmanager.AbstractFetchFieldManager.fetchObjectField(AbstractFetchFieldManager.java:104)
 [java]     at org.datanucleus.state.AbstractStateManager.replacingObjectField(AbstractStateManager.java:1197)
 [java]     at com.vobject.grailsfuse.User.jdoReplaceField(User.groovy)
 [java]     at com.vobject.grailsfuse.User.jdoReplaceFields(User.groovy)
 [java]     at org.datanucleus.state.JDOStateManagerImpl.replaceFields(JDOStateManagerImpl.java:2772)
 [java]     at org.datanucleus.state.JDOStateManagerImpl.replaceFields(JDOStateManagerImpl.java:2791)
 [java]     at org.datanucleus.state.JDOStateManagerImpl.loadFieldsInFetchPlan(JDOStateManagerImpl.java:1610)
 [java]     at org.datanucleus.ObjectManagerImpl.performDetachAllOnCommitPreparation(ObjectManagerImpl.java:3192)
 [java]     at org.datanucleus.ObjectManagerImpl.preCommit(ObjectManagerImpl.java:2931)
 [java]     at org.datanucleus.TransactionImpl.internalPreCommit(TransactionImpl.java:369)
 [java]     at org.datanucleus.TransactionImpl.commit(TransactionImpl.java:256)
 [java]     at org.datanucleus.jpa.EntityTransactionImpl.commit(EntityTransactionImpl.java:104)
 [java]     at org.grails.jpa.JpaPluginSupport$__clinit__closure3_closure6_closure11_closure38.doCall(JpaPluginSupport.groovy:452)
 [java]     at BootStrap$_closure1.doCall(BootStrap.groovy:13)
 [java]     at com.google.appengine.tools.development.JettyContainerService.startContainer(JettyContainerService.java:152)
 [java]     at com.google.appengine.tools.development.AbstractContainerService.startup(AbstractContainerService.java:116)
 [java]     at com.google.appengine.tools.development.DevAppServerImpl.start(DevAppServerImpl.java:218)
 [java]     at com.google.appengine.tools.development.DevAppServerMain$StartAction.apply(DevAppServerMain.java:162)
 [java]     at com.google.appengine.tools.util.Parser$ParseResult.applyArgs(Parser.java:48)
 [java]     at com.google.appengine.tools.development.DevAppServerMain.<init>(DevAppServerMain.java:113)
 [java]     at com.google.appengine.tools.development.DevAppServerMain.main(DevAppServerMain.java:89)

请指教。 看看您对出什么问题有任何想法...

谢谢。

Answer 1

对于更新，我将appengine-gorm插件发布到grails插件存储库，这是我编写该插件以支持批量插入操作的动机。 经过多次尝试后，由于无法使用在Google App Engine中运行的注释（@OneToMany）建立一对多关系，因此我决定手动管理该关系，而不使用映射。 但是，当我尝试在一对多关系的许多方面保存对象时，我面临着Google App Engine请求超时的问题。 然后，我发现数据存储支持的低级API在一个API调用中保留了许多对象，因此该插件诞生了。 希望对您和其他人有益。

最后，我设法使一对多关系手动工作并且没有映射。 请在http://grailsfuse.vobject.com/上观看名为GrailsFuse的实时演示应用程序。

我欢迎您的反馈和意见。 请随时通过limcheekin vobject dot com给我发送电子邮件。

谢谢。

Answer 2

看起来问题在于您在角色上没有用户，因为您需要在我认为的集合上指定maptedBy。

@OneToMany(mappedBy="user",fetch=FetchType.EAGER)
Set<Role> roles 

另外，由于您并不是真正在应用程序引擎中使用表，因此您实际上并不需要连接表的内容。 本质上，该角色将存在于用户实体下。

希望有帮助:)