概述:
我正在构建一个 spring-boot 应用程序，它部分地从外部 REST 服务中检索一些实体，并将其与数据库中本地保存的实体的先前版本进行比较。
我正在注入(inject) EntityManager与 @PersistenceContext ，并使用它来处理数据库，因为有许多实体类型，并且该类型最初对模块是未知的。我可以得到 JpaRepository来自工厂，但不同实体类型的数量可能会增长，如果可能的话，我宁愿不依赖它。
问题:
当模块检索到它不在数据库中的实体时，它会执行一些业务逻辑，然后尝试持久化新实体。Person类是所讨论的实体之一，它包含三个 Site 类型的字段，它们通常持有相同的对象。
当我试图坚持一个新的Person具有相同的 Site具有 CascadeType.PERSIST 的多个字段中的对象，我得到一个 EntityExistsException (参见堆栈跟踪(1))。
当我从 Site 中删除 CascadeType.PERSIST 时字段，并尝试持久化一个新的 Person具有相同的 Site多个字段中的对象，我得到一个 TransientPropertyValueException (参见堆栈跟踪(2))。
我想我理解这两种异常发生的原因:
@Transactional注释试图在没有持久化站点实例的情况下刷新事务。 我试过删除
@Transactional自己注释并开始并提交一个 EntityTransaction，但我得到一个 IllegalStateException (请参阅堆栈跟踪(3))，尽管我认为这是预期的，因为 spring 应该自己处理事务。我查看了类似问题的答案(例如 this 、 this )，但都建议更改 CascadeType。
在另一个问题中，有人建议确保
equals() 正确评估了相关实体。方法，所以我检查了调试器，((Person)newEntity).currentSite.equals(((Person)newEntity).homeSite)评估为真。如何在多个字段中始终保持/合并具有相同对象的实体？
编辑:我还用
fetch = FetchType.EAGER 尝试了级联类型的各种组合。 , 但这不会改变它们各自的异常。编辑 2:我试过使用
JpaRepository而不是使用 EntityManager ，并根据我使用的级联类型有效地获得相同的异常集。如果我使用
PERSIST ，但没有 MERGE ，我得到一个 EntityNotFoundException (参见stacktrace (4))，如果我同时使用PERSIST和 MERGE我得到一个 InvalidDataAccessApiUsageException`(请参阅 stacktrace (5))。联系人:
@EqualsAndHashCode(callSuper = true)
@javax.persistence.Entity
@XmlDiscriminatorValue("person")
@XmlRootElement(name = "person")
@XmlAccessorType(XmlAccessType.FIELD)
@XmlSeeAlso({Subscriber.class})
public class Person extends MobileResource implements Serializable {
private static final Logger LOG = LogManager.getLogger(Person.class);
private String firstName;
private String surname;
public Person() {
super();
}
public Person(Long id) {
super(id);
}
public Person(Person that) {
super(that);
this.firstName = that.firstName;
this.surname = that.surname;
}
// getters && setters
}
移动资源:
@EqualsAndHashCode(callSuper = true)
@Entity
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
@XmlRootElement(name = "resource")
@XmlDiscriminatorNode("@type")
@XmlAccessorType(XmlAccessType.FIELD)
@XmlSeeAlso({Vehicle.class, Person.class})
public abstract class MobileResource extends Resource implements Serializable {
private static final Logger LOG = LogManager.getLogger(MobileResource.class);
@ManyToOne(cascade = CascadeType.ALL)
private MobileResourceStatus status;
private Long incidentId;
@ManyToOne(fetch = FetchType.LAZY, cascade = {CascadeType.PERSIST, CascadeType.REMOVE, CascadeType.DETACH})
private Site homeSite;
@ManyToOne(fetch = FetchType.LAZY, cascade = {CascadeType.PERSIST, CascadeType.REMOVE, CascadeType.DETACH})
private Site currentSite;
@ManyToOne(fetch = FetchType.LAZY, cascade = {CascadeType.PERSIST, CascadeType.REMOVE, CascadeType.DETACH})
private Site relocationSite;
public MobileResource() {
super();
}
public MobileResource(Long id) {
super(id);
}
public MobileResource(MobileResource that) {
super(that);
this.status = that.status;
this.incidentId = that.incidentId;
this.homeSite = that.homeSite;
this.currentSite = that.currentSite;
this.relocationSite = that.relocationSite;
}
// getters && setters
}
网站:
@EqualsAndHashCode(callSuper = true)
@javax.persistence.Entity
public class Site extends Resource implements Serializable {
private static final Logger LOG = LogManager.getLogger(Site.class);
private String location;
public Site() {
super();
}
public Site(Long id) {
super(id);
}
public Site(Site that) {
super(that);
this.location = that.location;
}
}
资源:
@EqualsAndHashCode
@MappedSuperclass
@XmlRootElement
@XmlSeeAlso({MobileResource.class})
public abstract class Resource implements Entity, Serializable {
private static final Logger LOG = LogManager.getLogger(Resource.class);
@Id
private Long id;
private String callSign;
@XmlPath(".")
private LatLon latLon;
private Long brigadeId;
private Long batchId;
@ManyToMany(cascade = CascadeType.ALL)
private List<Attribute> attributes;
@ManyToOne(fetch = FetchType.LAZY, cascade = {CascadeType.PERSIST, CascadeType.REMOVE, CascadeType.DETACH})
private ResourceType type;
public Resource() {
}
public Resource(Long id) {
this.id = id;
}
public Resource(Resource that) {
this.id = that.id;
this.callSign = that.callSign;
this.latLon = that.latLon;
this.attributes = that.attributes;
this.batchId = that.batchId;
this.brigadeId = that.brigadeId;
this.type = that.type;
}
// getters && setters
}
默认实体消息处理程序:
@Component
public class DefaultEntityMessageHandler implements EntityMessageHandler {
@PersistenceContext
private EntityManager entityManager;
@Override
@Transactional
public void handleEntityMessage(EntityMessageData data, Message message) {
// business logic
if (newEntity != null) {
if (oldEntity != null)
entityManager.merge(newEntity);
else
entityManager.persist(newEntity);
}
}
}
堆栈跟踪 (1):
2018-06-06 12:05:15,975 ERROR ActiveMQMessageConsumer - ID:cpt-9225-1528283097161-1:1:1:1 Exception while processing message: ID:cpt-8919-1528281875592-1:1:1:1:4
javax.persistence.EntityExistsException: A different object with the same identifier value was already associated with the session : [my.class.path.entity.resource.site.Site#738]
at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:118)
at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:157)
at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:164)
at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:813)
at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:773)
at org.hibernate.jpa.event.internal.core.JpaPersistEventListener$1.cascade(JpaPersistEventListener.java:80)
at org.hibernate.engine.internal.Cascade.cascadeToOne(Cascade.java:467)
at org.hibernate.engine.internal.Cascade.cascadeAssociation(Cascade.java:392)
at org.hibernate.engine.internal.Cascade.cascadeProperty(Cascade.java:193)
at org.hibernate.engine.internal.Cascade.cascade(Cascade.java:126)
at org.hibernate.event.internal.AbstractSaveEventListener.cascadeBeforeSave(AbstractSaveEventListener.java:414)
at org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:252)
at org.hibernate.event.internal.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:182)
at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:125)
at org.hibernate.jpa.event.internal.core.JpaPersistEventListener.saveWithGeneratedId(JpaPersistEventListener.java:67)
at org.hibernate.event.internal.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:189)
at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:132)
...
更改 MobileResource 中的级联类型:
@ManyToOne(fetch = FetchType.LAZY, cascade = {CascadeType.REMOVE, CascadeType.DETACH})
private Site homeSite;
@ManyToOne(fetch = FetchType.LAZY, cascade = {CascadeType.REMOVE, CascadeType.DETACH})
private Site currentSite;
@ManyToOne(fetch = FetchType.LAZY, cascade = {CascadeType.REMOVE, CascadeType.DETACH})
堆栈跟踪 (2):
2018-06-06 12:19:24,084 ERROR ExceptionMapperStandardImpl - HHH000346: Error during managed flush [org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing : my.class.path.entity.resource.mobile_resource.person.Person.currentSite -> my.class.path.entity.resource.site.Site]
2018-06-06 12:19:24,093 ERROR ActiveMQMessageConsumer - ID:cpt-9436-1528283955454-1:1:1:1 Exception while processing message: ID:cpt-8919-1528281875592-1:1:1:1:8
org.springframework.dao.InvalidDataAccessApiUsageException: org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing : my.class.path.entity.resource.mobile_resource.person.Person.currentSite -> my.class.path.entity.resource.site.Site; nested exception is java.lang.IllegalStateException: org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing : my.class.path.entity.resource.mobile_resource.person.Person.currentSite -> my.class.path.entity.resource.site.Site
at org.springframework.orm.jpa.EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(EntityManagerFactoryUtils.java:365)
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:227)
at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:540)
at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:746)
at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:714)
...
堆栈跟踪 (3):
2018-06-06 13:29:35,594 ERROR ActiveMQMessageConsumer - ID:cpt-9864-1528288166188-1:1:1:1 Exception while processing message: ID:cpt-8919-1528281875592-1:1:1:1:9
java.lang.IllegalStateException: Not allowed to create transaction on shared EntityManager - use Spring transactions or EJB CMT instead
at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:254)
at com.sun.proxy.$Proxy114.getTransaction(Unknown Source)
at my.class.path.entity_controller.DefaultEntityMessageHandler.handleEntityMessage(DefaultEntityMessageHandler.java:60)
at my.class.path.entity_listener.listeners.IdExtractorMessageListener.onMessage(IdExtractorMessageListener.java:41)
...
堆栈跟踪 (4)
Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2018-06-06 15:26:36,143 ERROR SpringApplication - Application run failed
java.lang.IllegalStateException: Failed to execute CommandLineRunner
at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:793)
at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:774)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:335)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1246)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1234)
at my.class.path.OfficerSubscription.main(OfficerSubscription.java:44)
Caused by: org.springframework.orm.jpa.JpaObjectRetrievalFailureException: Unable to find my.class.path.entity.resource.site.Site with id 738; nested exception is javax.persistence.EntityNotFoundException: Unable to find my.class.path.entity.resource.site.Site with id 738
at org.springframework.orm.jpa.EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(EntityManagerFactoryUtils.java:373)
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:227)
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.translateExceptionIfPossible(AbstractEntityManagerFactoryBean.java:507)
at org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible(ChainedPersistenceExceptionTranslator.java:61)
at org.springframework.dao.support.DataAccessUtils.translateIfNecessary(DataAccessUtils.java:242)
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:153)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
...
堆栈跟踪 (5)
Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2018-06-06 15:31:54,840 ERROR SpringApplication - Application run failed
java.lang.IllegalStateException: Failed to execute CommandLineRunner
at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:793)
at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:774)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:335)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1246)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1234)
at my.class.path.OfficerSubscription.main(OfficerSubscription.java:44)
Caused by: org.springframework.dao.InvalidDataAccessApiUsageException: Multiple representations of the same entity [my.class.path.entity.resource.site.Site#738] are being merged. Detached: [FJE84 - Uckfield]; Detached: [FJE84 - Uckfield]; nested exception is java.lang.IllegalStateException: Multiple representations of the same entity [my.class.path.entity.resource.site.Site#738] are being merged. Detached: [FJE84 - Uckfield]; Detached: [FJE84 - Uckfield]
at org.springframework.orm.jpa.EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(EntityManagerFactoryUtils.java:365)
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:227)
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.translateExceptionIfPossible(AbstractEntityManagerFactoryBean.java:507)
at org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible(ChainedPersistenceExceptionTranslator.java:61)
at org.springframework.dao.support.DataAccessUtils.translateIfNecessary(DataAccessUtils.java:242)
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:153)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:135)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:61)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212)
at com.sun.proxy.$Proxy122.save(Unknown Source)
at my.class.path.OfficerSubscription.run(OfficerSubscription.java:81)
at my.class.path.OfficerSubscription$$FastClassBySpringCGLIB$$705870eb.invoke(<generated>)
...
最佳答案
经过几天的搜索，我终于在我的spring boot项目中解决了这个问题。
在 application.yaml 中添加以下 block 文件:
spring:
jpa:
properties:
hibernate:
enable_lazy_load_no_trans: true
event:
merge:
entity_copy_observer: allow
关于java - 如何使用 spring-boot 和 JPA 持久化包含另一个未持久化实体的多个相同实例的新实体？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/50721043/