我有一个Post实体和一个Post，目前正在尝试将DTO映射到实体，但是它给了我一个 Qualifier error. No method found annotated with @Named#value: [ getUserByUsername ]. --任何帮助都会非常感谢，这些是我当前的文件：

PostDTO：

@Getter
@Setter
public class PostDTO {
    private String author;
    @Size(max = 755)
    private String content;
}

员额实体：

@Entity
@Table(name = "POST")
@Getter
@Setter
@AllArgsConstructor
@NoArgsConstructor
public class Post {
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    @NotNull
    @ManyToOne(fetch = FetchType.EAGER, cascade= CascadeType.ALL)
    @JoinColumn(name = "POSTS")
    private User author;
    @Column(name = "POSTED_AT", nullable = false)
    private LocalDateTime dateTime;
    @Size(max = 755)
    @Column(name = "CONTENT", nullable = false, length = 755)
    private String content;
}

PostMapper：

@Mapper(componentModel = "spring", unmappedTargetPolicy = ReportingPolicy.IGNORE, uses = {MappingUtil.class, PostRepository.class})
public interface PostMapper {
    // since the author attribute on postDTO is a String, we use mapstruct to find
    // within our database the matching user to that username and return the user object
    @Mapping(source = "author", target = "author", qualifiedByName = {"getUserByUsername"})
    Post toEntity(PostDTO postDTO);
    PostDTO toDTO(Post post);
}

MappingUtils：

@Component
public class MappingUtil {
    private final UserRepository userRepository;
    MappingUtil(UserRepository userRepository) {
        this.userRepository = userRepository;
    @BeanMapping(qualifiedByName = "getUserByUsername")
    public User getUserByUsername(String username){
        return userRepository.findByUsername(username);
}

因此，每当我运行构建时，映射程序都找不到 @Named 注释，getUserByUsername方法在MappingUtil类上使用，我尝试了几种方法，但似乎无法修复它