如何从 Grails 服务中访问 EntityManager (JPA + GAE)

发布于 2024-10-03 04:52:04 字数 972 浏览 0 评论 0原文

我在从 grails 服务中访问 EntityManager 时遇到问题：

我的设置如下...

带有 AppEngine 和 GORM-JPA 插件的基本 Grails 应用程序
几乎所有内容的默认设置。我还没有接触过 resources.groovy、persistence.xml 等。

有些东西很好...

我只需添加“defentityManager”就可以从控制器内访问 EntityManager。

但是...

我有一个服务，我试图从中访问 EntityManager，但是，我收到“java.lang.IllegalStateException：EntityManager 已关闭！”例外。

插件是否在某处关闭了 EntityManager？我是否需要以某种方式更改 EntityManager 的范围？我是否需要更新一些 XML 文件以确保正确注入？

class GoogleCalendarService 实现 InitializingBean {
    无效 afterPropertiesSet() {
    }


 def 实体管理器


   公共 OAuthToken getAccessToken(用户 u) {
       //无法从这里访问entityManager
       entityManager.newQuery(...) //抛出IllegalStateException
   }


}

一个奇怪的注释：由于某种原因，如果我在 Jetty 启动并运行时重新保存服务，则该服务只能访问 EntityManager 一次。如果我单击重新加载（并让控制器再次访问该服务），该服务将无法再访问 EntityManager...

原文

I'm having trouble accessing the EntityManager from within a grails service:

My setup is as follows...

Basic Grails application with the AppEngine and GORM-JPA plugins
Default settings for pretty much everything. I haven't touched resources.groovy, persistence.xml etc.

Some things are good...

I am able to access the EntityManager from within controllers by simply adding "def entityManager".

But...

I have a service that I'm trying to access the EntityManager from, however, I get a "java.lang.IllegalStateException: EntityManager is already closed!" exception.

Is a plugin closing the EntityManager somewhere? Do I need to change the scope of the EntityManager somehow? Is there some XML file I need to update to ensure proper injection?

class GoogleCalendarService implements InitializingBean {
    void afterPropertiesSet() {
    }


   def entityManager


   public OAuthToken getAccessToken(User u) {
       //can't access entityManager from here
       entityManager.newQuery(...) //throws an IllegalStateException
   }

}

One weird note:
For some reason, if I re-save the service while Jetty is up and running the service is able to access the EntityManager just once. If I click reload (and have the controller access the service again) the service can no longer access the EntityManager...

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浮华 2024-10-10 04:52:04

我想正确的方法是使用 EntityManagerFactory，如下所示：

import org.springframework.orm.jpa.EntityManagerFactoryUtils

class GoogleCalendarService implements InitializingBean {
    void afterPropertiesSet() {

    }

    def entityManagerFactory
    EntityManager em

    public OAuthToken getAccessToken(User u) {
        em = EntityManagerFactoryUtils.getTransactionalEntityManager(entityManagerFactory)
        //do stuff with em
    }
}

I guess the right way to do this is use the EntityManagerFactory, like this:

import org.springframework.orm.jpa.EntityManagerFactoryUtils

class GoogleCalendarService implements InitializingBean {
    void afterPropertiesSet() {

    }

    def entityManagerFactory
    EntityManager em

    public OAuthToken getAccessToken(User u) {
        em = EntityManagerFactoryUtils.getTransactionalEntityManager(entityManagerFactory)
        //do stuff with em
    }
}

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