Spring数据lazyload没有LazyInitializationException

Question

@Component
@Transactional
public class TestClass extends AbstractClass
{
   @Autowire
   ClassARepo classARepo;

   @Override
   public void test() {
       ClassA classA = classARepo.findOne(1);
       List<ClassB> list = classA.getClassBs();
       list.size();
   }
}

ClassB 被映射为 onetomany 并延迟加载。

在上面的代码中

classARepo.findOne(1);

正确执行。但是

List<ClassB> list = classA.getClassBs();
list.size();

因 LazyInitializationException 失败。

public interface ClassARepo extends CrudRepository<ClassA, Integer> {
}

TestA 的实例创建如下所示

@PersistJobDataAfterExecution
@DisallowConcurrentExecution
@Transactional
@Component
public class TestClassJOB extends AbstractJob
{
    @Autowired
    TestClass indexer;
}

上下文：

<!-- JPA mapping configuration -->
<bean id="persistenceXmlLocation" class="java.lang.String">
    <constructor-arg value="classpath:/persistence.xml"></constructor-arg>
</bean>

<!-- entity manager -->
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean" 
    p:dataSource-ref="dataSource" p:persistenceUnitName="jpaData"
    p:persistenceXmlLocation-ref="persistenceXmlLocation">
    <property name="packagesToScan" value="com..persist.entity" />
    <property name="jpaVendorAdapter">
        <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" />
    </property>
</bean>

<!-- transaction manager -->
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager" 
    p:entityManagerFactory-ref="entityManagerFactory" lazy-init="true" p:dataSource-ref="dataSource" />

<!-- JPA repositories -->
<jpa:repositories base-package="com..persist.repo" 
    entity-manager-factory-ref="entityManagerFactory" transaction-manager-ref="transactionManager" />

我尝试了很多资源都无法解决问题。显示以下错误消息 "could not initialize proxy - no Session".

问题的原因可能是什么？当调用 classARepo.findOne(1) 时会话可用，为什么在延迟获取期间不可用 (list.size())?

Answer 1

问题是 TestClassJOB 的实例是由 Quartz 创建的。所以跨国代理没有应用到 class 这就是问题的原因。

我通过声明交易模板解决了这个问题

@Autowired
TransactionTemplate transactionTemplate;

然后将代码包装在

中

    transactionTemplate.execute(new TransactionCallbackWithoutResult()
    {
        @Override
        protected void doInTransactionWithoutResult(TransactionStatus status)
        {
           <code here>
        }
   }

Spring数据lazyload没有LazyInitializationException

Spring Data lazyload does not LazyInitializationException

spring

spring-data

lazy-loading

transactional