带有Spring的EclipseLink-无法持久到Db中 [英] EclipseLink with Spring - Can't persist into Db

问题描述

我正在使用Spring + EclipseLink 2来管理Derby数据库上的实体.从数据库中选择对象工作正常，但是当我尝试保留一个对象时，什么也没发生.程序正确执行，并且不会引发异常.由于我对Spring不熟悉，我可能做错了，感谢您的评论和建议:)

I am using Spring + EclipseLink 2 to manage entity on a Derby database. Select object from db works fine but when I try to persist one, nothing happens. Program executes correctly and no exception are thrown. I probably did something wrong, as I'm not familiar with Spring, thanks for your comments and suggestions :)

ServerDaoDb方法:

The ServerDaoDb method :

@Transactional
public void addServer(Server server) {
    EntityManager em = emf.createEntityManager();
    emf.createEntityManager().persist(server);
    em.close();
}

应用程序上下文为:

 ... 
 <tx:annotation-driven />

    <bean id="entityManagerFactory"
        class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean">
        <property name="persistenceUnitName" value="SpringPratiquePU" />
    </bean>

    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
    <property name="entityManagerFactory" ref="entityManagerFactory"/>
</bean>
<bean 
class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />
<bean class="org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor"/>

Persistence.xml:

Persistence.xml :

  <persistence-unit name="SpringPratiquePU" transaction-type="RESOURCE_LOCAL">
    <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
    <class>net.athom.spring.examples.models.eas.Server</class>
    <class>net.athom.spring.examples.models.eas.Node</class>
    <properties>
      <property name="eclipselink.target-database" value="DERBY"/>
      <property name="javax.persistence.jdbc.url" value="jdbc:derby://localhost:1527/SpringPratique"/>
      <property name="javax.persistence.jdbc.password" value="clem"/>
      <property name="javax.persistence.jdbc.driver" value="org.apache.derby.jdbc.ClientDriver"/>
      <property name="javax.persistence.jdbc.user" value="clem"/>
    </properties>
  </persistence-unit>
</persistence>

调试跟踪:

DEBUG JpaTransactionManager:365 - Creating new transaction with name [net.athom.spring.examples.service.impl.ServerManagerImpl.addServer]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT; ''
[EL Info]: 2010-10-29 15:33:27.443--ServerSession(14894886)--EclipseLink, version: Eclipse Persistence Services - 2.0.2.v20100323-r6872
[EL Info]: 2010-10-29 15:33:28.606--ServerSession(14894886)--file:/C:/netbeanProject/SpringPratique/src/_SpringPratiquePU login successful
15:33:28,893       DEBUG JpaTransactionManager:323 - Opened new EntityManager [org.eclipse.persistence.internal.jpa.EntityManagerImpl@1779885] for JPA transaction
15:33:28,951       DEBUG DefaultListableBeanFactory:242 - Returning cached instance of singleton bean 'transactionManager'
15:33:28,952       DEBUG JpaTransactionManager:286 - Found thread-bound EntityManager [org.eclipse.persistence.internal.jpa.EntityManagerImpl@1779885] for JPA transaction
15:33:28,953       DEBUG JpaTransactionManager:470 - Participating in existing transaction
15:33:29,266       DEBUG JpaTransactionManager:752 - Initiating transaction commit
15:33:29,267       DEBUG JpaTransactionManager:462 - Committing JPA transaction on EntityManager [org.eclipse.persistence.internal.jpa.EntityManagerImpl@1779885]
15:33:29,268       DEBUG JpaTransactionManager:548 - Closing JPA EntityManager [org.eclipse.persistence.internal.jpa.EntityManagerImpl@1779885] after transaction
15:33:29,308       DEBUG EntityManagerFactoryUtils:328 - Closing JPA EntityManager

推荐答案

您的错误在这里:

@Transactional
public void addServer(Server server) {
    EntityManager em = emf.createEntityManager();
    emf.createEntityManager().persist(server);
    em.close();
}

您正在创建两个不同的EntityManager实例，您正在关闭的em，以及在下一行与emf.createEntityManager()的新实例，您将直接使用它们来保存更改.

Your are creating two different EntityManager instances, the em, which you are closing, and a new one at the next line with emf.createEntityManager() which you are using directly to persist your changes.

尝试一下:

@Transactional
public void addServer(Server server) {
    EntityManager em = emf.createEntityManager();
    em.persist(server);
    em.close();
}

我猜想，当您关闭em实例时，所做的更改将写入数据库，但是，如果没有更改，则必须在关闭em实例之前添加em.flush();.

I guess that when you close your em instance, your changes are written to the DB, but, in case that they are not, you have to add em.flush(); right before closing the em instance.

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