mapstruct 将实体 OneToMany 映射到 DTO 并反向

Question

我试图用一个mapstruct，我需要映射Entity与子Entity列表，我有关系，oneToMany而且manyToOne，我需要在这两种情况下的映射：

@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将具有一个嵌套DeliveredEmailInfoDTO对象（多对一关系），而您的根DeliveredEmailInfoDTO将具有嵌套EmailDTO对象列表（一对多关系）并且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 

}