Spring Boot + Hibernate + JPA没有可用的事务性EntityManager

小编典典

Spring Boot + Hibernate + JPA没有可用的事务性EntityManager

spring-boot

我在Hibernate上通过JPA使用Spring Boot 1.2.3.RELEASE版本。我遇到以下异常

org.springframework.dao.InvalidDataAccessApiUsageException: No transactional EntityManager available; nested exception is javax.persistence.TransactionRequiredException: No transactional EntityManager available
at org.springframework.orm.jpa.EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(EntityManagerFactoryUtils.java:410) ~[EntityManagerFactoryUtils.class:4.1.6.RELEASE]
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:223) ~[HibernateJpaDialect.class:4.1.6.RELEASE]
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.translateExceptionIfPossible(AbstractEntityManagerFactoryBean.java:417) ~[AbstractEntityManagerFactoryBean.class:4.1.6.RELEASE]
at org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible(ChainedPersistenceExceptionTranslator.java:59) ~[ChainedPersistenceExceptionTranslator.class:4.1.6.RELEASE]
at org.springframework.dao.support.DataAccessUtils.translateIfNecessary(DataAccessUtils.java:213) ~[DataAccessUtils.class:4.1.6.RELEASE]
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:147) ~[PersistenceExceptionTranslationInterceptor.class:4.1.6.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) [ReflectiveMethodInvocation.class:4.1.6.RELEASE]
at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodIntercceptor.invoke(CrudMethodMetadataPostProcessor.java:122) ~[CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodIntercceptor.class:na]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) [ReflectiveMethodInvocation.class:4.1.6.RELEASE]
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92) [ExposeInvocationInterceptor.class:4.1.6.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) [ReflectiveMethodInvocation.class:4.1.6.RELEASE]
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:207) [JdkDynamicAopProxy.class:4.1.6.RELEASE]
at com.sun.proxy.$Proxy110.deleteByCustomerId(Unknown Source) ~[na:na]

Caused by: javax.persistence.TransactionRequiredException: No transactional EntityManager available
at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:275) ~[SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.class:4.1.6.RELEASE]
at com.sun.proxy.$Proxy102.remove(Unknown Source) ~[na:na]
at org.springframework.data.jpa.repository.query.JpaQueryExecution$DeleteExecution.doExecute(JpaQueryExecution.java:270) ~[JpaQueryExecution$DeleteExecution.class:na]
at org.springframework.data.jpa.repository.query.JpaQueryExecution.execute(JpaQueryExecution.java:74) ~[JpaQueryExecution.class:na]
at org.springframework.data.jpa.repository.query.AbstractJpaQuery.doExecute(AbstractJpaQuery.java:97) ~[AbstractJpaQuery.class:na]
at org.springframework.data.jpa.repository.query.AbstractJpaQuery.execute(AbstractJpaQuery.java:88) ~[AbstractJpaQuery.class:na]
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:395) ~[RepositoryFactorySupport$QueryExecutorMethodInterceptor.class:na]
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:373) ~[RepositoryFactorySupport$QueryExecutorMethodInterceptor.class:na]

以下是我的程序结构
Configuration类

@Configuration
@ComponentScan
@EnableAutoConfiguration
@EnableTransactionManagement
public class WSApplication {
    public static void main(final String[] args) {
        SpringApplication.run(WSApplication.class, args);
    }
}

@Entity
@Table(Orders)
public class Order {
    @id
    @GeneratedValue
    private long id;

    @Column(name = "customerId")
    private Long customerId;

    // getter & setter methods
    // equals & hashCode methods
}

public interface OrderRepository extends JpaRepository<Order, Long> {

    List<Order> findByCustomerId(Long customerId);

    // 4- @Transactional works fine
    void deleteByCustomerId(Long cusotmerId);

}

public class OrderService {

    @Autowired
    private OrderRepository repo;

    // 3- @Transactional works fine
    public void deleteOrder(long customerId){
        //1- throws exception
        repo.deleteByCustomerId(customerId);

        //2- following works fine
        //repo.delete(repo.findByCustomerId(customerId).get(0));
    }

}

在上面的服务类代码中，谁能指导我为什么2起作用而1抛出异常。

谢谢

阅读 1303

2020-05-30

共1个答案

小编典典

首先，我引用Spring-Data JPA文档来说明为什么该delete方法在您的情况下有效（我的意思是选项 2
）。

默认情况下，存储库实例上的CRUD方法是事务性的。对于读取操作，将事务配置readOnly标志设置为true，所有其他标志都配置为纯文本，@Transactional以便应用默认事务配置。有关详细信息，请参见CrudRepository的JavaDoc。

该delete方法实际上是的方法CrudRepository。您的存储库JpaRepository可以扩展CrudRespository，而扩展则可以扩展，因此它属于CrudRepository接口，并且根据上面的引用是事务性的。

如果阅读了“ 事务性查询方法 ”一节，您将看到与选项
4 相同的内容，并且您将知道如何对存储库的所有方法应用自定义事务行为。此外，文档的 示例61 显示了与选项 3 相同的场景。

现在请记住，您不是在使用JDBC逻辑，在这种情况下，数据库会处理事务，但要在基于ORM的框架中进行。ORM框架需要事务才能触发对象高速缓存和数据库之间的同步。因此，您必须了解并为执行ORM逻辑的方法提供事务上下文deleteByCustomerId。

默认情况下@Transactional（我的意思是没有任何参数）将传播模式设置REQUIRED为false，将readOnly标志设置为false。调用其中注释的方法时，如果不存在任何事务，则会初始化事务。这就是为什么的原因，
解决办法 @LucasSaldanha的（同例如 使用一个门面来定义多个库调用交易 ）和选项 4个作品。否则，如果没有事务，您将陷入选项
1 的抛出异常。

2020-05-30