java - mapstruct 映射实体 OneToMany 到 DTO 和反向

Question

我正在尝试使用 mapstruct我需要将 Entity 映射到子 Entity 列表，我有 oneToMany 和 manyToOne 关系，我需要两种情况下的映射:

@Data
@Entity
public class EmailEntity {

private int id;  

... // some fields

@ManyToOne
private DeliveredEmailInfoEntity deliveredEmailInfo;

}

.

@Data
@Entity
public class DeliveredEmailInfoEntity {

private int id;

... // some fields  

@OneToMany
private List<EmailEntity> emails;

}

映射到:

@Data
public class EmailDTO {

private int id;  

... // some fields

private DeliveredEmailInfoDTO deliveredEmailInfo;

}

.

@Data
public class DeliveredEmailInfoDTO {

private int id;

... // some fields  

private List<EmailDTO> emails;

}

如何以最好的方式做到这一点？

Answer 1

为了避免嵌套字段的无限交叉设置，您应该限制这种依赖性，例如在第二个嵌套级别上，即您的根 EmailDTO 将有一个嵌套的 DeliveredEmailInfoDTO 对象(多对一关系)，而您的根 DeliveredEmailInfoDTO 将具有嵌套的 EmailDTO 对象列表(一对多关系)，而在下一个嵌套级别上没有任何内容:

@Mapper(uses = DeliveredEmailInfoMapper.class)
public interface EmailMapper {

    @Mapping(target = "deliveredEmailInfo.emails", ignore = true)
    EmailDTO toDTO(EmailEntity entity);

    // other methods omitted 

    @Named("emailDTOList")
    default List<EmailDTO> toEmailDTOList(List<EmailEntity> source) {
        return source
                .stream()
                .map(this::toDTO)
                .peek(dto -> dto.setDeliveredEmailInfo(null))
                .collect(Collectors.toList());
    }
}

@Mapper(uses = EmailMapper.class)
public interface DeliveredEmailInfoMapper {

    @Mapping(target = "emails", source = "emails", qualifiedByName = "emailDTOList")
    DeliveredEmailInfoDTO toDTO(DeliveredEmailInfoEntity entity);

    // other methods omitted 

}