java集合仍然存在，但不会出现在另一侧

Question

我在Hibernate中有一段多对多的关系。当我把一个物体和两个物体联系起来时，物体就是物体。getObjectB（）成功返回两个元素（包括数据库），但是objectB。getObjectA（）不返回objectA。只有在新的课程开始后才有效

@Entity
public class ObjectA implements java.io.Serializable {

    private List<ObjectB> objectsB;

    ...

    @ManyToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
    @JoinTable(name = "db_objectA_objectB", joinColumns = {
        @JoinColumn(name = "idObjectA", updatable = false)}, inverseJoinColumns = {
        @JoinColumn(name = "idObjectB", updatable = false)})
    public List<ObjectB> getObjectsB() {
        return objectsB;
    }

    public void setObjectsB(List<ObjectB> objectsB) {
        this.objectsB = objectsB;
    }
}

@Entity
public class ObjectB implements java.io.Serializable {

    private List<ObjectA> objectsA;

    ...

    @ManyToMany(fetch = FetchType.EAGER, mappedBy = "objectsB", cascade = CascadeType.ALL)
    public List<ObjectA> getObjectsA() {
        return objectsA;
    }

    public void setObjectsA(List<ObjectA> objectsA) {
        this.objectsA= objectsA;
    }
}

Answer 1

保持关系双方的一致性是应用程序代码的责任，而不是Hibernate的责任。在JPA 2.0规范中，这是通过以下文字来说明的：

Note that it is the application that bears responsibility for maintaining the consistency of run- time relationships—for example, for insuring that the “one” and the “many” sides of a bidirectional relationship are consistent with one another when the application updates the relationship at runtime.