在JPA中将主键映射到复合键

Question

我有2个表，即user和user_session。

@Entity
@Table(name="user")
public class User {
    @Id
    @Email
    @Column(name = "user_id")
    private String userId;

    @Column(name = "password")
    private String password;

    @Column(name = "fname")
    private String fname;

    @OneToMany(fetch = FetchType.LAZY)
    @JoinColumn(name = "userId", referencedColumnName = "user_id")
    private UserSession userSession;
}

@Entity
@Table(name="user_session")
public class UserSession{
    @EmbeddedId
    private UserSessionPK userSessionPK;

    @Column(name = "remote_ip")
    private String remoteIp;
}

@Embeddable
public class UserSessionPK implements Serializable {
    private static final long serialVersionUID = 1L;

    @Column(name = "user_id")
    private String userId;

    @Temporal(TemporalType.TIMESTAMP)
    @Column(name = "time_in")
    private Date timeIn;
}

Answer 1

移除mappedBy属性。当您具有双向关系时，使用此属性来指示关系的哪一方是所有者。

但是您需要设置外键，也就是JoinColumn

@JoinColumn("user_id")
@OneToMany(fetch = FetchType.LAZY)
private UserSession userSession;