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;
}

@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;
}

@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看起来是这样的：

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，这样我就可以将if作为参数传递给VTypeDaoImpl）？

没有工厂类来获得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，我发现您希望在映射过程中对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）提交。MapStruct不会将此类类视为源或目标。但是，它将在该类中调用生命周期方法。请看一下这个示例：https://github.com/mapstruct/mapstruct-examples/tree/master/mapstruct-jpa-child-parent/src。

它是基于jpa的，但是您可以很容易地将它映射到您的问题…