我有父子关系,当我尝试通过父级更新添加新子级时,我的问题就出现了。
当我的 parent 短暂时,一切正常
CreditCard cc = new CreditCard("1234");
//User
User u1 = new User("KILLER");
u1.addCreditCard(cc); // bi-directional happens here inside.
// An autowired Spring Data repository that implements CrudRepository
userRepository.save(u1);
Assert.assertEquals(1, u1.getCreditCardCollection().size());
Assert.assertNotNull
(
u1.getCreditCardCollection()
.stream()
.findFirst()
.get()
.getIdCreditCard()
);
以上测试已成功执行,并为 cc 对象生成了 ID。
但是当我这样做时:
User u2 = new User("Foo Bar McLoud"); // u2 is transient
userRepository.save(u2); // Now u2 is persistent
u2 = userRepository.findOne(u2.getIdLogin());// just to be sure I´m working with a persistent object ;)
CreditCard ccNew = new CreditCard("77777");
u2.addCreditCard(ccNew );// bidirectional happens here inside
userRepository.save(u2); // should insert a new credit card right???
Assert.assertEquals("User should have 1 credit card.",
1, u2.getCreditCardCollection().size()); // PASS
Set<CreditCard> ccs = u2.getCreditCardCollection();
for (CreditCard cc : ccs) {
Assert.assertNotNull("CreditCard ID is null", cc.getIdCreditCard()); // FAIL: id is not generated. The database entry was not set. Added credit card is still transient...
}
因此,在我的第二次测试中,我的 ccNew 在其父级更新后仍然是暂时的。
为什么它仍然是短暂的?
子配置:
@JoinColumn(name = "id_user")
@ManyToOne(optional = false)
private User user;
父配置:
@OneToMany(mappedBy = "user")
@org.hibernate.annotations.Cascade(org.hibernate.annotations.CascadeType.ALL)
private Set<CreditCard> creditCardCollection = new HashSet<>();
已经在父级上尝试过:
@OneToMany(mappedBy = "user",cascade=javax.persistence.CascadeType.ALL)
private Set<CreditCard> creditCardCollection = new HashSet<>();
最佳答案
您在一个事务中测试工作,在此您使用 (u2.getCreditCardCollection()) 使用对象中的值而不是实体中的值(尚未执行保存):
Assert.assertEquals("User should have 2 credit cards.", 1, u2.getCreditCardCollection().size());
当您迭代 u2.getCreditCardCollection() 并检查 id 时,它们为 null,因为插入和 id 生成仅在提交阶段或刷新/清除上下文中进行。
您需要调用 saveAndFlush() 而不是只调用 save()。
u2 = userRepository.findOne(u2.getIdLogin());
CreditCard ccNew = new CreditCard("77777");
u2.addCreditCard(ccNew );// bidirectional happens here inside
userRepository.saveAndFlush(u2);
Assert.assertEquals("User should have 2 credit cards.",
1, u2.getCreditCardCollection().size()); // PASS
Set<CreditCard> ccs = u2.getCreditCardCollection();
for (CreditCard cc : ccs) {
Assert.assertNotNull("CreditCard ID is null", cc.getIdCreditCard());
}
来自 API;
void flush() Flushes all pending changes to the database.
S saveAndFlush(S entity) Saves an entity and flushes changes instantly
关于Java Hibernate + spring-data : Cascading Childs not working when Parent is persistent,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/44915428/