我在 SO 上搜索了类似的问题,但没有找到非常具体的答案。
我是 Springboot 的新手。我在服务层定义了一个POJO。我想将存储库注入(inject)到此类中。不知何故,它总是null
。这是我的代码结构,
文件:service/ResultInstitute.java
@Document(indexName = "result_institute")
public class ResultInstitute implements Serializable {
@Inject
public CourseRepository courseRepository;
/**
*
*/
private static final long serialVersionUID = -2168910694195614091L;
public ResultInstitute(Institute institute) {
// Initialize all the values.
for (Course course : institute.getCourses()){
HashMap<String, String> courseDetails = courseRepository.getCourseDetails(course.getId());
course.setCourseDetails(courseDetails);
courses.add(course);
}
courses = institute.getCourses();
for (Course course : courses){
subCategories.put(course.getSubCategory().getId(), course.getSubCategory().getDisplayName());
categories.put(course.getSubCategory()
.getCategory()
.getId(),
course.getSubCategory()
.getCategory()
.getDisplayName());
}
}
public ResultInstitute (){}
private Long id;
private String code; ....
文件:repository/CourseRepository.java
public interface CourseRepository extends JpaRepository<Course,Long> {
@Query("select distinct course from Course course left join fetch course.institutes")
List<Course> findAllWithEagerRelationships();
@Query("select course from Course course left join fetch course.institutes where course.id =:id")
Course findOneWithEagerRelationships(@Param("id") Long id);
@Query(value="SELECT DISTINCT(ci.course_details) FROM course_institute ci WHERE ci.courses_id = ?1", nativeQuery = true)
HashMap<String, String> getCourseDetails(Long id);
}
每当我尝试使用courseRepository
时,它都会给我NullPointerException
。你能帮我解决这个问题吗?
最佳答案
在评论部分,您说您按如下方式启动 ResultInstitute 类,
ResultInstitute resultInstitute = new ResultInstitute(i); resultInstitute.locationFilterString(i);
启动是由您自己处理的,因此 @Autowired 在这种情况下不起作用。 @Autowired是一个注入(inject)bean的spring配置,因此为了注入(inject)Repository ResultInstitute应该由Spring Iteself处理。
我们必须告诉spring ResultInstitute是一个bean类,你可以将ResultIntitute类注释为@Component
@Component
public class ResultInititute
因此,每当您想要实例化 ResultInstitute 时,请使用 @Autowired 实例化为 bean 类
@Autowired
ResultInstitute resultInstitute;
And Using the Respository in Entity class is not good thing, we have to handle this in separate section.
关于java - SpringBoot : Inject repository into a class defined in service layer,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/36651457/