如何配置EclipseLink 2.0和Spring 3.0.5以及Tomcat 6？

Question

我的Web应用程序使用Tomcat 6.0.18和Spring 3.0.5以及eclipselink 2.0.1和javax.persistence 2.0.0,SQL Server数据库.我无法弄清楚配置,也无法找到具有此类配置的工作示例.我尝试将loadTimeWeaver的属性添加到entityManagerFacotory中,但它在Spring 3中破坏了AutoWired批注,如下面的applicationContext.xml中所示:

<context:load-time-weaver/>

在appname-servlet.xml中:

但是当我禁用LoadTimeWeaver时,我的应用程序可以从JPA代码创建数据库,但无法将数据保存到数据库中.

<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="persistenceXmlLocation" value="classpath:persistence.xml" />
        <property name="dataSource" ref="dataSource" />         
        <property name="persistenceUnitName" value="restfulPU" />
        <property name="jpaVendorAdapter">
        <bean class="org.springframework.orm.jpa.vendor.EclipseLinkJpaVendorAdapter">
            <property name="showSql" value="true"/>
            <property name="generateDdl" value="true"/>
            <property name="databasePlatform" value="org.eclipse.persistence.platform.database.SQLServerPlatform"/>
        </bean>
        </property>
        <property name="jpaDialect">
        <bean class="org.springframework.orm.jpa.vendor.EclipseLinkJpaDialect" />
        </property>         
        <property name="jpaPropertyMap">
        <props>
            <prop key="eclipselink.weaving">false</prop>
        </props>
        </property>         
</bean> 

<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
    <property name="entityManagerFactory" ref="entityManagerFactory" />
</bean> 
<tx:annotation-driven transaction-manager="transactionManager"/>
  Persistence.xml
<persistence-unit name="restfulPU" transaction-type="RESOURCE_LOCAL">
    <class>com.generalform.eclipselink.model.Todo</class>
    <properties>
        <!-- EclipseLink should create the database schema automatically -->
        <property name="eclipselink.ddl-generation" value="drop-and-create-tables" />
        <property name="eclipselink.ddl-generation.output-mode"
           value="database" />
    </properties>

如果您能指导我将EclipseLink集成到Spring 3和Tomcat中,我将非常感激.

Answer 1

谢谢,詹姆斯.

在http://static.springsource.org/spring/docs/3.0.0.M4/reference/html/ch13s05.html上的Springsource指南之后,Tomcat 6开始编织.指南中提到的步骤在此处复制:

Step1.Copy spring-tomcat-weaver.jar到$ CATALINA_HOME/lib,其中$ CATALINA_HOME表示Tomcat安装的根目录)

第2步.通过修改context.xml告诉Tomcat使用自定义类加载器:

<Context path="/myWebApp" docBase="/my/webApp/location">
    <Loader loaderClass="org.springframework.instrument.classloading.tomcat.TomcatInstrumentableClassLoader"
        useSystemClassLoaderAsParent="false"/>
</Context>

我在$ CATALINA_HOME/conf/context.xml中没有指定path和docBase属性

第三步.将loadTimeWeaver属性设置为LocalContainerEntityManagerFactoryBean

<bean id="emf" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
  <property name="loadTimeWeaver">
    <bean class="org.springframework.instrument.classloading.ReflectiveLoadTimeWeaver"/>
  </property>
</bean> 

然后,我再次启动Tomcat 6,启动过程变得干净.但是,数据仍然无法持久存储到数据库中.错误如下:

不允许在共享的EntityManager上创建事务 - 使用Spring事务或EJB CMT

我的同事在这一点上通过指出使用@Transactional处理Spring事务而不使用实体管理器上的事务来避免上述问题来救了我.然后我注释掉em.getTransaction().begin()和em.getTransaction().commit(),只留下em.persist(todo).todo是这里的实体.它立即起作用.在这里,开发人员应该意识到JPA事务和Spring事务之间的区别.事实上,当EclipseLink/JPA使用Spring Transaction Management时,这是一个困惑的部分.

我也尝试过Tomcat 7,因为我认为它可能与Tomcat有关.实际上,这个问题与Tomcat版本无关.

启用LoadTimeWeaver后,它可以处理数据持久性.以下是applicationname-servlet.xml中transactionManager配置部分的工作版本:

   <context:property-placeholder location="classpath:generalform.properties"/>
   <context:component-scan base-package="com.generalform" />

   <tx:annotation-driven transaction-manager="transactionManager"/> 
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
    <property name="driverClassName" value="${mysql.database.driver}" />
    <property name="url" value="${mysql.database.url}" />
    <property name="username" value="${mysql.database.user}" />
    <property name="password" value="${mysql.database.password}" />
</bean>

<bean id="emf" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="persistenceXmlLocation" value="classpath:persistence.xml" />
        <property name="dataSource" ref="dataSource" />         
        <property name="persistenceUnitName" value="restfulPU" />
        <property name="jpaVendorAdapter">
        <bean class="org.springframework.orm.jpa.vendor.EclipseLinkJpaVendorAdapter">
            <property name="showSql" value="true"/>
            <property name="generateDdl" value="true"/>
            <property name="databasePlatform" value="org.eclipse.persistence.platform.database.MySQLPlatform"/>
        </bean>
        </property>
        <property name="jpaDialect">
        <bean class="org.springframework.orm.jpa.vendor.EclipseLinkJpaDialect" />
        </property>
        <property name="loadTimeWeaver">
        <bean class="org.springframework.instrument.classloading.ReflectiveLoadTimeWeaver" />
        </property>         

</bean> 

<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
    <property name="entityManagerFactory" ref="emf" />
</bean> 

下面是我的Dao类,以正式方式,try/catch应该包含在方法内部的代码中:

@Repository("todoDao")
public class TodoDao {  

    @PersistenceContext
    private EntityManager em;


    public void saveTodo(Todo todo) {

        System.out.println("TodoDao:saveTodo into DB >>>");
        //em.getTransaction().begin();
        em.persist(todo);
        //em.getTransaction().commit();
        em.close();
        System.out.println("TodoDao: complete saveTodo into DB close()>>>");
    }   

}   

TodoService类使用@Transactional注释声明Spring Transaction,@ Autowired在启用LoadTimeWeaver后也正在工作:

@Service("todoService")
@Transactional(propagation = Propagation.SUPPORTS, readOnly = true)
public class TodoService {
    @Autowired
    private TodoDao todoDao;

    public TodoService() {
    }

    @Transactional(propagation = Propagation.REQUIRED, readOnly = false)
    public void saveTodo(Todo todo) {
        System.out.println("TodoService -> saveTodo is called!");
        todoDao.saveTodo(todo);
    }
}