我使用@EnableTransactionManagement运行Sping Boot 应用程序，并希望使用@Transactional(readOnly = true)进行一些数据库查询。
但是我收到了一个令人困惑的错误消息。我正在使用Spring，Sping Boot 和Spring Data JPA。
MySpringBootApplication.java

@SpringBootApplication
@EnableTransactionManagement
@ComponentScan("com.deutscheboerse.regrephub")
@EntityScan(basePackages = "com.deutscheboerse.regrephub")
@EnableJpaRepositories(basePackages = "com.deutscheboerse.regrephub")
@Slf4j
public class MySpringBootApplication
{
   ... Some @Autowired variables ...

   public static void main(String[] args)
   {
      SpringApplication.run(MySpringBootApplication.class, args);
   }

   ... 
}

MySpringBootApplicationConfiguration.java

@Configuration
@EnableEncryptableProperties
@EnableTransactionManagement
@EnableAsync
@Slf4j
public class MySpringBootApplicationConfiguration
{
   ... Some @Autowired variables ...

   @Bean
   @ConfigurationProperties(prefix = "spring.datasource")
   public DataSource dataSource()
   {
      return DataSourceBuilder
            .create(this.dataSourceProperties.getClassLoader())
            .url(this.dataSourceProperties.getUrl())
            .username(this.dataSourceProperties.getUsername())
            .password(this.dataSourceProperties.getPassword())
            .build();
    }

    ...
}

MyBeanDao.java

@Repository
public interface MyBeanDao extends JpaRepository<MyBeanData, Long>
{
    @QueryHints(value = @QueryHint(name = HINT_FETCH_SIZE, value = "" + Integer.MIN_VALUE))
    @Query(value = "SELECT * FROM MY_TABLE", nativeQuery = true)
    @Transactional(readOnly = true)
    Stream<MyBeanData> streamAll();
}

MyBeanService.java

@Service
@Slf4j
public class MyBeanService extends AbstractService
{
    @Autowired
    public MyBeanService(...)
    {
       ...
    }

    @Override
    @Transactional(readOnly = true, propagation = Propagation.SUPPORTS)
    public void handleRequest(Object request, Message msg)
    {
       try (Stream<MyBeanData> data = myBeanDao.streamAll())
       {
          ...
       }
       catch (Exception e)
       {
          ...
       }
    }
}

当我运行SpringBootApplication时，我将收到以下日志消息/错误：

[TransactionInterceptor:474] Getting transaction for [org.springframework.data.jpa.repository.support.SimpleJpaRepository.streamAll]
[TransactionInterceptor:517] Completing transaction for [org.springframework.data.jpa.repository.support.SimpleJpaRepository.streamAll] after exception: org.springframework.dao.InvalidDataAccessApiUsageException: You're trying to execute a streaming query method without a surrounding transaction that keeps the connection open so that the Stream can actually be consumed. Make sure the code consuming the stream uses @Transactional or any other way of declaring a (read-only) transaction.
[RuleBasedTransactionAttribute:131] Applying rules to determine whether transaction should rollback on org.springframework.dao.InvalidDataAccessApiUsageException: You're trying to execute a streaming query method without a surrounding transaction that keeps the connection open so that the Stream can actually be consumed. Make sure the code consuming the stream uses @Transactional or any other way of declaring a (read-only) transaction.
[RuleBasedTransactionAttribute:148] Winning rollback rule is: null
[RuleBasedTransactionAttribute:153] No relevant rollback rule found: applying default rules

首先，JPA打开一个事务，然后立即关闭它，但出现了一个异常，即我想执行一个没有周围事务的流查询方法。