Question

我正在使用Hibernate中的Many-To-One编写程序，当我在DAO中编写以下代码时：

sessionFactory = HibernateUtility.createSessionFactory();
            session = sessionFactory.openSession();
           PatientEntity patientEntity=new PatientEntity();
           DoctorEntity doctorEntity=(DoctorEntity) session.get(DoctorEntity.class, doctorId);
         System.out.println(doctorEntity);
           if (doctorEntity!= null) 
           {
               System.out.println("hello");
                patientEntity.setId(patient.getId());
                patientEntity.setName(patient.getName());
                patientEntity.setAge(patient.getAge());
                patientEntity.setPhoneNumber(patient.getPhoneNumber());
                patientEntity.setDoctor(doctorEntity);
            }

            session.getTransaction().begin();
            session.persist(patientEntity);
            session.getTransaction().commit();t the

我得到以下异常：

org.hibernate.id.IdentifierGenerationException: ids for this class must be manually assigned before calling save(): entity.PatientEntity

我的实体课程：

@Entity
@Table(name="Doctor")
public class DoctorEntity {
    @Id
    @Column(name="id")
    private String id;
    private String name;
    private String phoneNumber;
    private String address;


    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getPhoneNumber() {
        return phoneNumber;
    }
    public void setPhoneNumber(String phoneNumber) {
        this.phoneNumber = phoneNumber;
    }
    public String getAddress() {
        return address;
    }
    public void setAddress(String address) {
        this.address = address;
    }
}

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

    @Id
    private Integer id;
    private String name;
    private String phoneNumber;
    private Integer age;
    @ManyToOne(cascade=CascadeType.ALL)
    @JoinColumn(name="id",unique=true,insertable=false,updatable=false)
    private DoctorEntity doctor;
    public Integer getId() 
    {
        return id;
    }
    public void setId(Integer id) 
    {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getPhoneNumber() {
        return phoneNumber;
    }
    public void setPhoneNumber(String phoneNumber) {
        this.phoneNumber = phoneNumber;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
    public DoctorEntity getDoctor() {
        return doctor;
    }
    public void setDoctor(DoctorEntity doctor) {
        this.doctor = doctor;
    }
}

我通过不同的链接，但无法将我的问题与它相关联。 Hibernate Many-To-One Relationship without Primary Key or Join Table

Repeated column in mapping for entity (should be mapped with insert="false" update="false")

Another Repeated column in mapping for entity error

Caused by: org.hibernate.MappingException: Repeated column in mapping for entity

感谢任何帮助！

Answer 1

您可能需要指定@GeneratedValue(strategy=GenerationType.AUTO)或使用自己的自定义生成器。

Answer 2

您需要在 Patient 类中使用您选择的生成策略指定 @GeneratedValue Annotation。

org.hibernate.id.IdentifierGenerationException：在调用save（）之前必须手动分配此类的ID：entity.PatientEntity

2 个答案: