java - 在mapstruct映射器中实现自定义行为的问题

Question

我有以下 DTO 类:

@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
public class Conclusion {

    private Integer id;
    // ......
    private List<CType> cTypes;
}

@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
public class CType {

    private Integer id;
    // ......
    private VType vType;
}

还有它们对应的实体类:

@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
@Entity
@Table(name = "conclusion")
public class Conclusion {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id", nullable = false, updatable = false)
    private Integer id;

    // ......

    @OneToMany
    @JoinColumn(name = "id")
    private List<CTypeEntity> cTypeEntities;
}

@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
@Entity
@Table(name = "c_types")
public class CTypeEntity {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id", nullable = false, updatable = false)
    private Integer id;

    // ......

    @Column(name = "v_type_id")
    private Integer vTypeId;
}

此外，所有相应的 Dao 和 JPA Repository 接口(interface)也都存在。现在，我正在编写我的 mapstruct Mapper 接口(interface)，该接口(interface)应用于将实体映射到 DTO，反之亦然。这是映射器:

@Mapper
public interface ConclusionMapper {

    @Mappings({
            @Mapping(target = "cTypes", source = "cTypeEntities")
    })
    Conclusion toConclusion(ConclusionEntity entity);

    List<Conclusion> toConclusionList(List<ConclusionEntity> entities);

    @Mappings({
            @Mapping(target = "cTypeEntities", source = "cTypes")
    })
    ConclusionEntity fromConclusion(Conclusion conclusion);

    List<ConclusionEntity> fromConclusionList(List<Conclusion> conclusions);

    @Mappings({
            @Mapping(target = "cType", source = "vTypeId", qualifiedByName = "formVType")
    })
    ConclusionTaxType toCType(CTypeEntity cTypeEntity);

    List<CType> toCTypes(List<CTypeEntity> cTypeEntities);

    CTypeEntity fromCType(CType cType);

    List<CTypeEntity> fromCTypeList(List<CType> cTypes);

    @Named("formVType")
    default VType formVType(CTypeEntity entity) {
        // TODO: instantiate a DAO which will return an instance of VType
        VTypeDao dao; // instantiate somehow

        return vTypeDao.findById(entity.getVId()); 
    }
}

VTypeDao 看起来像这样:

public interface VTypeDao {
    VType findById(int id);

    boolean exists(int id);

    List<VType> findAll();
}

@Component
public class VTypeDaoImpl implements VTypeDao {
    private final VTypeRepo vTypeRepo;

    public VTypeDaoImpl(VTypeRepo vTypeRepo) {
        this.vTypeRepo = vTypeRepo;
    }

    // ............................. method implementations
}

我的问题是:如何实例化 VTypeDao 的对象(或者至少是 VTypeRepo，以便我可以将 if 作为参数传递给 VTypeDaoImpl)？

没有工厂类来获取 VTypeDao 的适当实现。

编辑: VTypeDao 及其实现是我的项目的第三方组件。

Answer 1

从您的评论中，我了解到您想在映射过程中对 VTypeDao 进行查找。您可以将其包装在另一个类中，并将其作为 @Context 注释为映射参数。 MapStruct 不会将此类视为源或目标。但是它会调用此类中的生命周期方法..看看这个示例:https://github.com/mapstruct/mapstruct-examples/tree/master/mapstruct-jpa-child-parent/src .

它基于 jpa，但您可以轻松地将其映射到您的问题..