Question

I have a problem with map many-to-one relationship. When I create mapper for one-to-one, that s OK.

@Entity
@Table(name = "PATIENT")
public class PatientEntity {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(nullable = false)
    private String firstName;

    @OneToOne(
            cascade = CascadeType.ALL,
            fetch = FetchType.LAZY,
            optional = false
    )
    private AddressEntity address;

    @OneToMany(mappedBy = "patient")
    private List<VisitEntity> visit;

My mapper for one-to-one relationship:

public final class PatientMapper {
    public static PatientTO mapToTO(final PatientEntity patientEntity)
    {
        if (patientEntity == null)
        {
            return null;
        }
        final PatientTO patientTO = new PatientTO();
        patientTO.setId(patientEntity.getId());
        patientTO.setFirstName(patientEntity.getFirstName());

        final AddressTO addressTO = new AddressTO();
        addressTO.setId(patientEntity.getAddress().getId());
        addressTO.setCity(patientEntity.getAddress().getCity());

        patientTO.setAddress(addressTO);

        return patientTO;
    }

    public static PatientEntity mapToEntity(final PatientTO patientTO)
    {
        if(patientTO == null)
        {
            return null;
        }
        PatientEntity patientEntity = new PatientEntity();
        patientEntity.setId(patientTO.getId());
        patientEntity.setFirstName(patientTO.getFirstName());

        AddressEntity addressEntity = new AddressEntity();
        addressEntity.setId(patientTO.getAddress().getId());
        addressEntity.setCity(patientTO.getAddress().getCity());

        patientEntity.setAddress(addressEntity);

        return patientEntity;
    }
}

• 如何为多到一的关系制定法典[私人名单和设计;VisitEntity> visit]?

事先感谢你的帮助。

Answer 1

You need to map the List<VisitEntity> in your PatientEntity to List<VisitTO> in your PatientTO and vice-versa. I m assuming you also have a VisitMapper that maps between VisitEntity and VisitTO.

例如:

import java.util.List;
import java.util.stream.Collectors;

public final class PatientMapper {
    public static PatientTO mapToTO(final PatientEntity patientEntity)
    {
        if (patientEntity == null)
        {
            return null;
        }
        final PatientTO patientTO = new PatientTO();
        patientTO.setId(patientEntity.getId());
        patientTO.setFirstName(patientEntity.getFirstName());

        final AddressTO addressTO = new AddressTO();
        addressTO.setId(patientEntity.getAddress().getId());
        addressTO.setCity(patientEntity.getAddress().getCity());
        
        // Map VisitEntity list to VisitTO list
        List<VisitTO> visitTOs = patientEntity.getVisits()
            .stream()
            .map(VisitMapper::mapToTO)
            .collect(Collectors.toList());
        patientTO.setVisits(visitTOs);

        patientTO.setAddress(addressTO);

        return patientTO;
    }

    public static PatientEntity mapToEntity(final PatientTO patientTO)
    {
        if(patientTO == null)
        {
            return null;
        }
        PatientEntity patientEntity = new PatientEntity();
        patientEntity.setId(patientTO.getId());
        patientEntity.setFirstName(patientTO.getFirstName());

        AddressEntity addressEntity = new AddressEntity();
        addressEntity.setId(patientTO.getAddress().getId());
        addressEntity.setCity(patientTO.getAddress().getCity());
        
        // Map VisitTO list to VisitEntity list
        List<VisitEntity> visitEntities = patientTO.getVisits()
            .stream()
            .map(VisitMapper::mapToEntity)
            .collect(Collectors.toList());
        patientEntity.setVisits(visitEntities);

        patientEntity.setAddress(addressEntity);

        return patientEntity;
    }
}

这一修改假定你有<条码>。访问Mapper 类别:ToTO和 。访问:<>。如果你不这样做,那么你将需要与您的“条码”相类似。 AddressMapper。

Still, remember to set the patient in each VisitEntity when you are mapping from VisitTO to VisitEntity, otherwise you will lose the link back to the patient.

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