Spring Boot - 查询方法公共抽象 java.util.stream.Stream

Question

我需要流式传输对象列表，但是当我使用 JpaRepository 和 @Query 尝试它时，我收到此异常：Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'MainApplication': Unsatisfied dependency expressed through field 'service'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'MyServiceImpl': Unsatisfied dependency expressed through field 'myDAO'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'MyDAO': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Validation failed for query for method public abstract java.util.stream.Stream com.my.package.dao.MyDAO.streamAll()!MyDAO 代码：@Repositorypublic interface MyDAO extends JpaRepository<MyEntity, Long> {    @QueryHints(value = @QueryHint(name = HINT_FETCH_SIZE, value = "" +         Integer.MIN_VALUE))    @Query(value = "SELECT m FROM MyEntity m")    Stream<MyEntity> streamAll();    ...}主要代码：@SpringBootApplication@ComponentScan("com.my.package.*")@EntityScan("com.my.package.*")@Configuration@EnableAutoConfigurationpublic class MainApplication implements CommandLineRunner {    @Autowired    MyServiceInterface service;    public static void main(String[] args) {        SpringApplication.run(MainApplication.class, args);    }    @Override    public void run(String... args) throws Exception {        try {            service.createCsv();        } catch (RuntimeException e) {            System.out.println(e);        }    }}我已经尝试了一切，但没有任何效果，请帮助我！

Answer 1

您将无法使用，Stream<MyEntity> findAll();因为JpaRepository已经定义了具有List返回类型的方法，因此您可以像这样重命名方法Stream<MyEntity> getAll();或使用 Ordering 将方法重命名为Stream<MyEntity> findAllByOrderByIdAsc();.

Answer 2

只需删除

@Query(value = "SELECT m FROM MyEntity m")

并使用 JPARepository 的 findAll() 方法，如下所示

Stream<MyEntity> findAll();