我有两节课:
家长班:
@Entity
@Table(name = "parent_object")
public class ParentObject {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id", unique = true, nullable = false)
private Long id;
@Column(name = "age", nullable = false)
private Long age;
@OneToOne(orphanRemoval = true, cascade = CascadeType.ALL, mappedBy = "parentObject")
private ChildObject childObject;
public ParentObject() {
}
public ParentObject(Long age, ChildObject childObject) {
this.age = age;
this.childObject = childObject;
}
public Long getId() {
return id;
}
public Long getAge() {
return age;
}
public ChildObject getChildObject() {
return childObject;
}
}
儿童班:
@Entity
@Table(name = "child_object")
public class ChildObject implements Serializable {
@Id
@OneToOne
@JoinColumn(name = "id")
private ParentObject parentObject;
@Column(name = "name")
private String name;
public ChildObject() {
}
public ChildObject(String name) {
this.name = name;
}
public ParentObject getParentObject() {
return parentObject;
}
public String getName() {
return name;
}
}
架构:
create table parent_object
(
id bigserial not null
constraint pk_parent_object
primary key,
age bigint not null
)
;
create table child_object
(
id bigint not null,
name varchar(32)
);
存储库:
@Component
public interface ParentObjectRepository extends JpaRepository<ParentObject, Long>, JpaSpecificationExecutor<ParentObject> {
}
保存对象时抛出错误:
ParentObject parentObject = new ParentObject(12L, new ChildObject("name"));
parentObjectRepository.save(parentObject);
错误讯息:
2017-04-13 09:27:27.672 DEBUG 4496 --- [io-12500-exec-1] org.hibernate.SQL : insert into parent_object (age) values (?)
Hibernate: insert into parent_object (age) values (?)
2017-04-13 09:27:27.677 DEBUG 4496 --- [io-12500-exec-1] org.hibernate.SQL : select currval('parent_object_id_seq')
Hibernate: select currval('parent_object_id_seq')
2017-04-13 09:27:27.688 DEBUG 4496 --- [io-12500-exec-1] org.hibernate.SQL : insert into child_object (name, id) values (?, ?)
Hibernate: insert into child_object (name, id) values (?, ?)
2017-04-13 09:27:27.693 WARN 4496 --- [io-12500-exec-1] o.h.engine.jdbc.spi.SqlExceptionHelper : SQL Error: 0, SQLState: 23502
2017-04-13 09:27:27.693 ERROR 4496 --- [io-12500-exec-1] o.h.engine.jdbc.spi.SqlExceptionHelper : ERROR: null value in column "id" violates not-null constraint
Detail: Failing row contains (null, name).
2017-04-13 09:27:27.694 INFO 4496 --- [io-12500-exec-1] o.h.e.j.b.internal.AbstractBatchImpl : HHH000010: On release of batch it still contained JDBC statements
2017-04-13 09:27:27.705 ERROR 4496 --- [io-12500-exec-1] c.r.c.c.s.mvc.advice.ExceptionAdvice : Unexpected server error occurred: could not execute statement; SQL [n/a]; constraint [id]; nested exception is org.hibernate.exception.ConstraintViolationException: could not execute statement
org.springframework.dao.DataIntegrityViolationException: could not execute statement; SQL [n/a]; constraint [id]; nested exception is org.hibernate.exception.ConstraintViolationException: could not execute statement
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.convertHibernateAccessException(HibernateJpaDialect.java:278) ~[spring-orm-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:244) ~[spring-orm-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:521) ~[spring-orm-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:761) ~[spring-tx-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:730) ~[spring-tx-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:504) ~[spring-tx-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:292) ~[spring-tx-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96) ~[spring-tx-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:136) ~[spring-tx-4.3.6.RELEASE.jar:4.3.6.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.6.RELEASE.jar:4.3.6.RELEASE]
....
Caused by: org.postgresql.util.PSQLException: ERROR: null value in column "id" violates not-null constraint
Detail: Failing row contains (null, name).
at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2455) ~[postgresql-9.4.1212.jre7.jar:9.4.1212.jre7]
at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:2155) ~[postgresql-9.4.1212.jre7.jar:9.4.1212.jre7]
at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:288) ~[postgresql-9.4.1212.jre7.jar:9.4.1212.jre7]
at org.postgresql.jdbc.PgStatement.executeInternal(PgStatement.java:430) ~[postgresql-9.4.1212.jre7.jar:9.4.1212.jre7]
at org.postgresql.jdbc.PgStatement.execute(PgStatement.java:356) ~[postgresql-9.4.1212.jre7.jar:9.4.1212.jre7]
at org.postgresql.jdbc.PgPreparedStatement.executeWithFlags(PgPreparedStatement.java:168) ~[postgresql-9.4.1212.jre7.jar:9.4.1212.jre7]
at org.postgresql.jdbc.PgPreparedStatement.executeUpdate(PgPreparedStatement.java:135) ~[postgresql-9.4.1212.jre7.jar:9.4.1212.jre7]
at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:204) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
... 106 common frames omitted
任何想法有什么问题,即为什么ChildObject没有从ParentObject获取id?
更新: 这是一个有效的代码:
@Entity
@Table(name = "parent_object")
public class ParentObject {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id", unique = true, nullable = false)
private Long id;
@Column(name = "age")
private Long age;
@OneToOne(cascade = CascadeType.ALL, mappedBy = "parentObject")
private ChildObject childObject;
public ParentObject() {
}
public ParentObject(Long age, ChildObject childObject) {
this.age = age;
this.childObject = childObject;
}
public Long getId() {
return id;
}
public Long getAge() {
return age;
}
public ChildObject getChildObject() {
return childObject;
}
public void setChildObject(ChildObject childObject) {
this.childObject = childObject;
}
}
@Entity
@Table(name = "child_object")
public class ChildObject {
@Id
@Column(name = "child_id", unique = true, nullable = false)
private Long id;
@MapsId
@OneToOne
@JoinColumn(name = "child_id")
private ParentObject parentObject;
@Column(name = "name")
private String name;
public ChildObject() {
}
public ChildObject(String name) {
this.name = name;
}
public Long getId() {
return id;
}
public ParentObject getParentObject() {
return parentObject;
}
public String getName() {
return name;
}
public void setParentObject(ParentObject parentObject) {
this.parentObject = parentObject;
}
}
但是,我真的不想将parentObject设置为ChildObject:
ChildObject childObject = new ChildObject("name");
ParentObject parentObject = new ParentObject(12L, childObject);
childObject.setParentObject(parentObject);
这是获得共享ID的唯一方法吗?如果未明确设置parentObject,则抛出以下错误:
Caused by: org.hibernate.id.IdentifierGenerationException: attempted to assign id from null one-to-one property [test.ChildObject.parentObject]
at org.hibernate.id.ForeignGenerator.generate(ForeignGenerator.java:83) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:101) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
at org.hibernate.jpa.event.internal.core.JpaPersistEventListener.saveWithGeneratedId(JpaPersistEventListener.java:67) ~[hibernate-entitymanager-5.0.11.Final.jar:5.0.11.Final]