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

我正在使用 Spring Boot 1.2.3.RELEASE 版本和 JPA over hibernate。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
配置类

@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，任何人都可以指导我为什么 2 有效而 1 抛出异常。

Thanks

首先，我引用一下Spring-Data JPA 文档 http://docs.spring.io/spring-data/jpa/docs/current/reference/html/来证明为什么delete方法适用于你的情况（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。为了 读取操作交易配置readOnly标志已设置 为 true，所有其他都配置为普通@Transactional以便 应用默认事务配置。详细信息请参阅 JavaDoc Crud存储库

The delete方法实际上是一个方法CrudRepository。您的存储库扩展JpaRepository这延伸了CrudRespository，所以它属于 CrudRepository 接口，并且根据上面的引用是事务性的。

如果您阅读了该部分事务查询方法 http://docs.spring.io/spring-data/jpa/docs/current/reference/html/#transactional-query-methods你会看到它与选项相同4您将了解如何为存储库的所有方法应用自定义事务行为。 另外，实施例61文档显示了与该选项相同的场景3.

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），而是在基于 ORM 的框架内进行操作。 ORM 框架需要事务来触发对象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，例如deleteByCustomerId.

默认情况下@Transactional（我的意思是没有任何参数）将传播模式设置为REQUIRED并将 readOnly 标志设置为 false。当您调用其中注释的方法时，如果不存在事务，则会初始化事务。这就是为什么解决方法@LucasSaldanha（与示例相同使用外观来定义多个存储库调用的事务）和选项4作品。否则，如果没有交易，你就会陷入期权抛出的异常1.