Spring Data JPA+JUnit 执行更新语句成功但数据库却未更新

原代码

public interface CarRepository extends JpaRepository<Car, Integer>
        , JpaSpecificationExecutor<Car> {
    @Modifying
    @Query("update Car c set c.status = :newStatus where c.id = :carId and c.status = :oldStatus")
    void updateStatusById(@Param(value = "carId") int carId, @Param(value = "oldStatus") int oldStatus, @Param(value = "newStatus") int newStatus);

}

@RunWith(SpringRunner.class)
@SpringBootTest
public class CarRepositoryTest {
    @Resource
    CarRepository carRepository;
    
	@Transactional
    @Test
    public void updateStatusById(){
        carRepository.updateStatusById(1,0,1);
        carRepository.updateStatusById(2,1,0);
    }
}

发现Junit测试成功，但查看数据库中的数据并未更新成功

于是查看日志输出发现最后有一行如下

2019-05-19 22:50:12.985  INFO 4204 --- [           main] o.s.t.c.transaction.TransactionContext   : Rolled back transaction for test: 

原来是事务回滚的缘故，对代码进行如下改动可以阻止事务回滚，注意@Transactional的位置

改动后的代码

public interface CarRepository extends JpaRepository<Car, Integer>
        , JpaSpecificationExecutor<Car> {

	@Transactional
    @Modifying
    @Query("update Car c set c.status = :newStatus where c.id = :carId and c.status = :oldStatus")
    void updateStatusById(@Param(value = "carId") int carId, @Param(value = "oldStatus") int oldStatus, @Param(value = "newStatus") int newStatus);

}

@RunWith(SpringRunner.class)
@SpringBootTest
public class CarRepositoryTest {
    @Resource
    CarRepository carRepository;
    
    @Test
    public void updateStatusById(){
        carRepository.updateStatusById(1,0,1);
        carRepository.updateStatusById(2,1,0);
    }
}