Java 对象关系上的eclipselink缓存

我有两个实体：

@Entity
public class CustomerMainInformation {
@Id @GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String name;

@Column(unique = true, length = 10)
private String customerNumber;
@OneToMany(mappedBy = "firstCustomerRelationship", cascade = CascadeType.ALL)
private List<CustomerRelationship> firstCustomerRelationship;

@OneToMany(mappedBy = "secondCustomerRelationship", cascade = CascadeType.ALL)
private List<CustomerRelationship> secondCustomerRelationship;
// setter & getter
}

@Entity
public class CustomerRelationship {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;

@ManyToOne
@JoinColumn(columnDefinition = "first")
private CustomerMainInformation firstCustomerRelationship;

@ManyToOne
@JoinColumn(columnDefinition = "second")
private CustomerMainInformation secondCustomerRelationship;

// setter & getter
}

在此代码中，关系大小增加，但由于在调用.getSecondCustomerRelationship（）之前，列表大小未更改

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如果@Cacheable（false）添加到CustomerRelationship，则.size（）返回正确的列表大小。

在显示的代码中，您似乎没有维护关系的双方。调用setSecondCustomerRelationship将设置它的一侧，这一侧控制数据库中的外键字段。但是java对象模型与更改不同步，除非您还将customerRelationship添加到CustomerMinInformation的集合中。JPA不会为你维护你的关系，所以如果你改变了一方，你就有责任让另一方保持同步

您可以设置双方，也可以在提交后强制从数据库刷新CustomerMinion信息。第一种选择要有效得多

    CustomerMainInformation customerMainInformation =manager.getReference(CustomerMainInformation.class, 1L);
    System.out.println(customerMainInformation.getFirstCustomerRelationship().size());
    System.out.println(customerMainInformation.getSecondCustomerRelationship().size());

    CustomerMainInformation customerMainInformation2 = manager.getReference(customerMainInformation.getClass(), 2L);
    CustomerRelationship customerRelationship = new CustomerRelationship();
    customerRelationship.setFirstCustomerRelationship(customerMainInformation2);
    customerRelationship.setSecondCustomerRelationship(customerMainInformation);
    manager.persist(customerRelationship);
    transaction.commit();

    EntityManager manager2 = factory.createEntityManager();
    CustomerMainInformation customerMainInformation3 =  manager2.getReference(CustomerMainInformation.class, 1L);
    System.out.println(customerMainInformation3.getFirstCustomerRelationship().size());
    System.out.println(customerMainInformation3.getSecondCustomerRelationship().size());