我正在创建Sping Boot 应用程序。这里有MediaContent实体：

@Entity
@AllArgsConstructor
@NoArgsConstructor
@Data
@Table(name = "media_content")
public class MediaContent extends AbstractEntity{

    @Column(unique = true)
    private String name;
    @Column
    @Lob
    private byte[] video;
    @Column
    @Lob
    private byte[] previewImage;
    @Column
    private String description;
    @Column
    @Enumerated(value = EnumType.STRING)
    private Status status;

    @ManyToOne(cascade = CascadeType.REFRESH, fetch = FetchType.EAGER)
    @JoinColumn
    private User user;

    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "content")
    private List<Like> likes = new ArrayList<>();

    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "content")
    private List<MediaComments> comments = new ArrayList<>();

    public enum Status{
        ACCEPTED, REJECTED, UNDER_REVIEW
        }
}

我还有MediaConentRepository、Service和Service Implementation

public interface MediaContentRepository extends JpaRepository<MediaContent, UUID> {
    MediaContent findMediaContentByName(String name);
}

public interface MediaContentService {

    List<MediaContent> findAllContent();

    List<MediaComments> findAllComments(MediaContent content);

    Integer getAllLikes(MediaContent content);

    boolean isLiked(MediaContent content, Principal principal);

    User getUserByPrincipal(Principal principal);

    MediaContent findContentById(UUID id);

    void updateMediaContent(MediaContent content, MultipartFile imageFile, MultipartFile videoFile) throws IOException;

    void addMediaContent(Principal principal, MediaContent content, MultipartFile imageFile, MultipartFile videoFile) throws IOException;

    boolean deleteMediaContent(User user, UUID id);
}

@Service
@RequiredArgsConstructor
public class MediaContentServiceImpl implements MediaContentService {

    private final MediaContentRepository repository;
    private final UserRepository userRepository;
    private final MediaCommentsRepository commentsRepository;

    @Override
    public List<MediaContent> findAllContent() {
        return repository.findAll().stream().filter(content -> content.getStatus()== MediaContent.Status.ACCEPTED).collect(Collectors.toList());
    }

    @Override
    public List<MediaComments> findAllComments(MediaContent content) {
        List<MediaComments> commentList = new ArrayList<>();
        commentsRepository.findAll().forEach(comments -> {
            if(comments.getMediaID().equals(content.getUuid())){
                commentList.add(comments);
            }
        });
        return commentList;
    }

    @Override
    public Integer getAllLikes(MediaContent content) {
        return content.getLikes().size();
    }

    @Override
    public boolean isLiked(MediaContent content, Principal principal) {
        User user = userRepository.findUserByUsername(principal.getName());
        if(content.getLikes().stream().filter(like->like.getUser()==user).count() == 1){
            return true;
        }
        return false;
    }

    @Override
    public MediaContent findContentById(UUID id) {
        return repository.findById(id).orElse(null);
    }

    @Override
    public void updateMediaContent(MediaContent content, MultipartFile imageFile, MultipartFile videoFile) throws IOException {
        MediaContent content1 = repository.findById(content.getUuid()).orElse(null);
        if(content1!=null){
            byte[] imageBytes = imageFile.getBytes();
            content.setPreviewImage(imageBytes);
            byte[] videoBytes = videoFile.getBytes();
            content.setVideo(videoBytes);
            content.setStatus(MediaContent.Status.UNDER_REVIEW);
            repository.delete(content1);
            repository.save(content);
        } else{
            log.error("not such content1 in database");
        }
    }

    @Override
    public void addMediaContent(Principal principal, MediaContent content, MultipartFile imageFile, MultipartFile videoFile) throws IOException {
        User user = getUserByPrincipal(principal);
        if(user.getRole() == User.Role.ADMIN){
            content.setStatus(MediaContent.Status.ACCEPTED);
        }
        content.setUser(user);
        byte[] imageBytes = imageFile.getBytes();
        byte[] videoBytes = videoFile.getBytes();
        content.setVideo(videoBytes);
        content.setPreviewImage(imageBytes);
        repository.save(content);
    }

    @Override
    public User getUserByPrincipal(Principal principal) {
        if (principal == null) return new User();
        return userRepository.findUserByUsername(principal.getName());
    }

    @Override
    public boolean deleteMediaContent(User user, UUID id) {
        MediaContent content = repository.findById(id).orElse(null);
        if(content!=null){
            if(content.getUser().getUuid().equals(user.getUuid())){
                repository.delete(content);
                return true;
            }
            log.error("Media content with id = {} is not found", id);

        } else{
            log.error("not such content in database");
        }
        return false;
    }
}

我想得到我所有的媒体内容。我为RestController写了两个不同的方法：

@RestController
@RequiredArgsConstructor
public class MediaContentController {
    private final MediaContentServiceImpl service;

    @PermitAll
    @GetMapping("/media")
    @ResponseBody
    private List<MediaContentResponse> getAllMediaContents(){
        List<MediaContent> contentList = service.findAllContent();
        List<MediaContentResponse> list = new ArrayList<>();
        contentList.forEach(content -> {
            list.add(new MediaContentResponse(
                    content.getUuid(), content.getName(), content.getDescription(), content.getUser()
            ));
        });
        return list;
    }

    @PermitAll
    @GetMapping("/media")
    public ResponseEntity<List<MediaContent>> getAll(){
        List<MediaContent> mediaContents = service.findAllContent();
        return ResponseEntity.ok(mediaContents);
    }
}

但在第一种情况下，我遇到了这个异常“无法调用”org.example.service.impl.MediaContentServiceImpl.findAllContent（）“，因为“this.service”为null”。当我使用第二个时，我得到数据
请帮帮我，问题出在哪里？我在其他控制器中也有类似的异常。我试图删除一些注解，将RestController更改为Controller，但这一切都没有t help me.您的文本`