Hibernate@OneToOne @NotNull
它是有效申报@OneToOne
,并@NotNull
在关系的双方,如:
class ChangeEntry{
@OneToOne(cascade=CascadeType.ALL)
@NotNull
ChangeEntryDetails changeEntryDetails;
public void addDetails(ChangeEntryDetails details) {
this.changeEntryDetails = details;
details.setChangeEntry(this);
}
}
class ChangeEntryDetails
{
@OneToOne(cascase=CascadeType.ALL)
@NotNull
ChangeEntry changeEntry;
public void setChangeEntry(ChangeEntry changeEntry)
{
this.changeEntry = changeEntry;
}
}
我找不到任何表明这是无效的信息,但似乎在持久性过程中,至少必须违反关系的一侧。(例如,如果首先写入changeEntry,则changeEntryDetails临时为null)。
尝试此操作时,我看到抛出了异常not-null property references a null or transient value
。
我想避免在可能的情况下放宽约束,因为双方都 存在。
回答:
声明
@OneToOne
并@NotNull
在关系的两边是否合法(…)我找不到任何表明无效的内容,但是在持久性过程中,似乎至少必须违反关系的一侧。(例如,如果changeEntry
先写,changeEntryDetails
则暂时为null)。
这是有效的,并且在正确映射的实体上一切正常。您需要将双向关联的一侧声明为“拥有”侧(此“控制”插入顺序)。一种可行的解决方案:
@Entity@NamedQueries( { @NamedQuery(name = ChangeEntry.FIND_ALL_CHANGEENTRIES, query = "SELECT c FROM ChangeEntry c") })
public class ChangeEntry implements Serializable {
public final static String FIND_ALL_CHANGEENTRIES = "findAllChangeEntries";
@Id
@GeneratedValue
private Long id;
@OneToOne(optional = false, cascade = CascadeType.ALL)
@JoinColumn(name = "DETAILS_ID", unique = true, nullable = false)
@NotNull
private ChangeEntryDetails changeEntryDetails;
public void addDetails(ChangeEntryDetails details) {
this.changeEntryDetails = details;
details.setChangeEntry(this);
}
// constructor, getters and setters
}
对于其他实体(请注意mappedBy
在关联的非所有权方设置的属性):
@Entitypublic class ChangeEntryDetails implements Serializable {
@Id
@GeneratedValue
private Long id;
@OneToOne(optional = false, mappedBy = "changeEntryDetails")
@NotNull
private ChangeEntry changeEntry;
// constructor, getters and setters
}
对于这些实体,以下测试(用于演示目的)通过:
public class ChangeEntryTest { private static EntityManagerFactory emf;
private EntityManager em;
@BeforeClass
public static void createEntityManagerFactory() {
emf = Persistence.createEntityManagerFactory("TestPu");
}
@AfterClass
public static void closeEntityManagerFactory() {
emf.close();
}
@Before
public void beginTransaction() {
em = emf.createEntityManager();
em.getTransaction().begin();
}
@After
public void rollbackTransaction() {
if (em.getTransaction().isActive()) {
em.getTransaction().rollback();
}
if (em.isOpen()) {
em.close();
}
}
@Test
public void testCreateEntryWithoutDetails() {
try {
ChangeEntry entry = new ChangeEntry();
em.persist(entry);
fail("Expected ConstraintViolationException wasn't thrown.");
} catch (ConstraintViolationException e) {
assertEquals(1, e.getConstraintViolations().size());
ConstraintViolation<?> violation = e.getConstraintViolations()
.iterator().next();
assertEquals("changeEntryDetails", violation.getPropertyPath()
.toString());
assertEquals(NotNull.class, violation.getConstraintDescriptor()
.getAnnotation().annotationType());
}
}
@Test
public void testCreateDetailsWithoutEntry() {
try {
ChangeEntryDetails details = new ChangeEntryDetails();
em.persist(details);
fail("Expected ConstraintViolationException wasn't thrown.");
} catch (ConstraintViolationException e) {
assertEquals(1, e.getConstraintViolations().size());
ConstraintViolation<?> violation = e.getConstraintViolations()
.iterator().next();
assertEquals("changeEntry", violation.getPropertyPath()
.toString());
assertEquals(NotNull.class, violation.getConstraintDescriptor()
.getAnnotation().annotationType());
}
}
@Test
public void validEntryWithDetails() {
ChangeEntry entry = new ChangeEntry();
ChangeEntryDetails details = new ChangeEntryDetails();
entry.addDetails(details);
em.persist(entry);
Query query = em.createNamedQuery(ChangeEntry.FIND_ALL_CHANGEENTRIES);
assertEquals(1, query.getResultList().size());
}
}
以上是 Hibernate@OneToOne @NotNull 的全部内容, 来源链接: utcz.com/qa/398996.html