在Grails中使用JPA域类

Question

我想在使用最新的Grails里程碑(2.0.0.M1)开发的应用程序中使用JPA域模型.JPA域类位于src\java应用程序的目录中.

基于这篇描述如何在Grails应用程序中使用现有JPA域模型的博客文章,我创建grails-app/conf/hibernate/hibernate.cfg.xml了一个带有JPA注释类的列表.

如果有人对自己想要运行应用程序感到厌倦,可以在这里找到它.运行应用程序时,启动时会发生以下错误

Error 2011-08-04 23:28:19,777 [Thread-8] ERROR context.GrailsContextLoader  - Error executing bootstraps: Error creati
ng bean with name 'grailsDomainClassMappingContext': Instantiation of bean failed; nested exception is org.springframewo
rk.beans.BeanInstantiationException: Could not instantiate bean class [org.codehaus.groovy.grails.domain.GrailsDomainCla
ssMappingContext]: Constructor threw exception; nested exception is java.lang.NullPointerException
   Line | Method
->> 303 | innerRun in java.util.concurrent.FutureTask$Sync
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|   138 | run      in java.util.concurrent.FutureTask
|   886 | runTask  in java.util.concurrent.ThreadPoolExecutor$Worker
|   908 | run      in     ''
^   662 | run . .  in java.lang.Thread

Caused by BeanInstantiationException: Could not instantiate bean class [org.codehaus.groovy.grails.domain.GrailsDomainCl
assMappingContext]: Constructor threw exception; nested exception is java.lang.NullPointerException
->> 303 | innerRun in java.util.concurrent.FutureTask$Sync
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|   138 | run      in java.util.concurrent.FutureTask
|   886 | runTask  in java.util.concurrent.ThreadPoolExecutor$Worker
|   908 | run      in     ''
^   662 | run . .  in java.lang.Thread

Caused by NullPointerException: null
->> 123 | addPersistentEntityInternal in org.grails.datastore.mapping.model.AbstractMappingContext
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|   115 | addPersistentEntity in     ''
|   127 | addPersistentEntityInternal in     ''
|   115 | addPersistentEntity in     ''
|   127 | addPersistentEntityInternal in     ''
|   115 | addPersistentEntity in     ''
|   303 | innerRun in java.util.concurrent.FutureTask$Sync
|   138 | run      in java.util.concurrent.FutureTask
|   886 | runTask  in java.util.concurrent.ThreadPoolExecutor$Worker
|   908 | run      in     ''
^   662 | run . .  in java.lang.Thread

奇怪的是,这个问题似乎只是由与其他域类有关系的域类触发.如果删除除SystemProperty(不引用其他域类)之外的所有域类,则应用程序启动时不会出错.

Answer 1

尝试使用META-INF/persistence.xml（example）（我不知道到底要把它放在哪里，但它最终应该放在WEB-INF/META-INF/persistence.xml，并在那里包含你的 jar 文件（在<jar-file>元素中）。然后当然你将需要所有相应的 spring beans（LocalEntityManagerFactoryBean例如）