org.springframework.orm.jpa.JpaSystemException：为：class oneToOne 生成空 id

Question

如题，当我尝试使用Spring Data jpa保存数据时出现以下异常。请帮我解决这个问题，因为我通过搜索熟悉的问题仍然无法解决。

课堂活动：

@Entity
@Table(name = "activity")
@Access(AccessType.FIELD)
public class Activity implements Serializable {

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String activityName;
private String startTime;
private String endTime;

@OneToOne(fetch = FetchType.LAZY, mappedBy = "activity", cascade = CascadeType.ALL, optional = false)
private ActivityContent activityContent;


private Integer isDelete;

@PrePersist
public void prePersist() {
    isDelete = 0;
}
//setters and getters
}

类活动内容：

@Entity
@Table(name = "activity_content")
@Access(AccessType.FIELD)
public class ActivityContent implements Serializable {

    @GenericGenerator(name = "generator", strategy = "foreign", parameters = @Parameter(name = "property", value = "activity"))
    @Id
    @GeneratedValue(generator = "generator")
    @Column(name = "activity_id", unique = true, nullable = false)
    private Long activityId;

    @Column(columnDefinition = "TEXT")
    private String content;

    @OneToOne(fetch = FetchType.LAZY)
    @PrimaryKeyJoinColumn
    private Activity activity;
//setters and getters
}

道接口：

public interface ActivityDao extends PagingAndSortingRepository<Activity,Long>,JpaSpecificationExecutor<Activity>{
}

在调用activityDao.save(activity)之前，我已经按照其他博客所说的将以下属性设置为activity和activityContent，但是没有用。

activityContent.setActivity(activity);
activity.setActivityContent(activityContent);
activityDao.save(activity);

如果有人帮助我，将不胜感激。

异常详情：

org.springframework.orm.jpa.JpaSystemException: null id generated for:class com.gauldin.activity.orm.ActivityContent; nested exception is org.hibernate.id.IdentifierGenerationException: null id generated for:class com.gauldin.activity.orm.ActivityContent
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.convertHibernateAccessException(HibernateJpaDialect.java:333)
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:244)
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.translateExceptionIfPossible(AbstractEntityManagerFactoryBean.java:488)
at org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible(ChainedPersistenceExceptionTranslator.java:59)
at org.springframework.dao.support.DataAccessUtils.translateIfNecessary(DataAccessUtils.java:213)
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:147)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:133)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:57)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213)
at com.sun.proxy.$Proxy123.save(Unknown Source)

Answer 1

在您的 ActivityContent 中尝试使用：

@OneToOne(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
@MapsId
@JoinColumn(name = "activity_Id", referencedColumnName = "id")
private Activity activity;

当您组装时，您应该将 ActivityContent 保存为 OneToOne 的所有者：

activityContent.setActivity(activity);
activityContentDao.save(activityContent);

如果您想保存 Activity，则必须将其设为拥有方。

编辑

同时尝试将生成器设置为：

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "activity_id", unique = true, nullable = false)
private Long activityId;