hibernate - 两个 OneToMany 集合到 Hibernate 中的同一个表

Question

我有一张用户表和一张用户之间的通话表。

public class User {

    @Id
    @Column(name="userId")
    private long userId;

    @OneToMany(mappedBy="caller")
    Set<Call> madeCalls;

    @OneToMany(mappedBy="callee")
    Set<Call> receivedCalls;

}

public class Call {

    @ManyToOne
    @JoinColumn(name="calleeId", referencedColumnName="userId")
    User callee;

    @ManyToOne
    @JoinColumn(name="callerId", referencedColumnName="userId")
    User caller;

}

为简洁起见，省略了 getter 和 setter 以及其他字段(id 等)等详细信息。

每次调用都涉及一名调用者和一名被调用者。每个用户都可以调用和接听许多电话。

简单地说:以上是 JPA 的有效使用，特别是 hibernate？

Answer 1

没有主键就无法拥有 hibernate 类。此外，您应该使用property-based acccess 而不是field-based access 否则hibernate 会给您编译时错误。您的代码应该是:

@Entity
@Table(name="user")
public class User {

    @Id // use all these annotation in  the getter method
    @GeneratedValue(strategy = GenerationType.AUTO, generator = "native")
    @GenericGenerator(name = "native", strategy = "native")
    private long userId;

    @OneToMany(mappedBy="caller") // use this annotation in  the getter method
    private Set<Call> madeCalls;

    @OneToMany(mappedBy="callee") // use this annotation in  the getter method
    private Set<Call> receivedCalls;

}

@Entity
@Table(name="call")
public class Call {

    @Id // use all these annotation in  the getter method
    @GeneratedValue(strategy = GenerationType.AUTO, generator = "native")
    @GenericGenerator(name = "native", strategy = "native")
    private long callId;

    @ManyToOne
    @JoinColumn(name="calleeId") // use this annotation in  the getter method
    private User callee;

    @ManyToOne
    @JoinColumn(name="callerId") // use this annotation in  the getter method
    private User caller;

}

Here is a very good tutorial for hibernate and performance .