Question

我有一个名为 employee 的生成表，作为两个表之间的关系：

人，的 MedicalCompany

我想知道如何在这个生成的表和另一个表之间建立manyToMany关系，如：

@ManyToMany(fetch = FetchType.EAGER)
    @JoinTable(name = "employee_role", joinColumns = { @JoinColumn(name = "employee_id") }, inverseJoinColumns = { @JoinColumn(name = "role_id") })
    private Set<Role> roles = new HashSet<Role>(0);

1- 生成表：

@SuppressWarnings("serial")
@Entity
@Table(name = "employee")
@AssociationOverrides(value = {
        @AssociationOverride(name = "pk.medicalCompany", joinColumns = @JoinColumn(name = "company_id", referencedColumnName = "id")),
        @AssociationOverride(name = "pk.person", joinColumns = @JoinColumn(name = "employee_id", referencedColumnName = "person_id")),
        @AssociationOverride(name = "pk.titleText"),
        @AssociationOverride(name = "pk.employeeManager") })
public class Employee implements Serializable {

    @EmbeddedId
    private EmployeeCompanyId pk = new EmployeeCompanyId();

    @Transient
    public void setEmployeeManager(long employeeManager) {
        this.pk.setEmployeeManager(employeeManager);
    }

    public long getEmployeeManager() {
        return pk.getEmployeeManager();
    }

    @Transient
    public void setTitleText(String titleText) {
        this.pk.setTitleText(titleText);
    }

    public String getTitleText() {
        return pk.getTitleText();
    }

    public void setPerson(Person person) {
        this.pk.setPerson(person);
    }

    @Transient
    public Person getPerson() {
        return this.pk.getPerson();
    }

    public void setMedicalCompany(MedicalCompany medicalCompany) {
        this.pk.setMedicalCompany(medicalCompany);
    }

    @Transient
    public MedicalCompany getMedicalCompany() {
        return this.pk.getMedicalCompany();
    }

    public void setPk(EmployeeCompanyId pk) {
        this.pk = pk;
    }

    public EmployeeCompanyId getPk() {
        return pk;
    }

}

2- EmployeeCompanyId ：

@SuppressWarnings("serial")
@Embeddable
public class EmployeeCompanyId implements Serializable {

    @ManyToOne
    private Person person;

    @ManyToOne
    private MedicalCompany medicalCompany;

    @Size(max = 150, message = "{long.value}")
    @Column(name = "title_text", length = 150, nullable = true)
    private String titleText;

    @Column(name = "employee_manager")
    private long employeeManager;

    public Person getPerson() {
        return person;
    }

    public void setPerson(Person person) {
        this.person = person;
    }

    public MedicalCompany getMedicalCompany() {
        return medicalCompany;
    }

    public void setMedicalCompany(MedicalCompany medicalCompany) {
        this.medicalCompany = medicalCompany;
    }

    public String getTitleText() {
        return titleText;
    }

    public void setTitleText(String titleText) {
        this.titleText = titleText;
    }

    public long getEmployeeManager() {
        return employeeManager;
    }

    public void setEmployeeManager(long employeeManager) {
        this.employeeManager = employeeManager;
    }

}

Answer 1

您不能在@Embeddable内@EmbeddedId之间建立关系。您只能在常规@Embeddable中建立关系。

JPA 2.0 FR规范， 11.1.15 EmbeddedId Annotation ：

嵌入式id类中定义的关系映射不是支持的

Hibernate 3.5 doc， 2.2.3.2.1。 @EmbeddedId属性

在嵌入式id对象中，关联表示为关联实体的标识符。但您可以通过@MapsId注释将其值链接到实体中的常规关联。

您可以做的最少是在嵌入中使用主键类型。然后，您可以将它们映射到可嵌入存在的实体。换句话说，你可以有类似的东西：

@Embeddable public class EmployeeCompanyId implements Serializable { private int personId; // ... } @Entity public class Employee { @EmbeddedId private EmployeeCompanyId pk = new EmployeeCompanyId(); @MapsId("personId") @ManyToOne private Person person; // ... }

如何在生成的实体中定义@ManyToMany

1 个答案: