带有 Kotlin 的 SpringBoot Hibernate 无法保存具有 OneToOne 关系的对象

Question

我正在开发一个获取宠物信息的 API，宠物必须有状态和类型，我是 Springboot 的新手，我可以获取与宠物相关的信息，但是当我尝试添加或更新宠物，似乎无法将信息保存在数据库中（我使用的是 MySQL）。

我每次尝试保存数据时收到的错误是：

org.hibernate.PersistentObjectException: detached entity passed to persist: androidcourseapi.models.StatusPet
    at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:120) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
    at org.hibernate.event.service.internal.EventListenerGroupImpl.fireEventOnEachListener(EventListenerGroupImpl.java:113) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
    at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:745) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
    at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:713) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
    at org.hibernate.engine.spi.CascadingActions$7.cascade(CascadingActions.java:298) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
    at org.hibernate.engine.internal.Cascade.cascadeToOne(Cascade.java:492) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
    at org.hibernate.engine.internal.Cascade.cascadeAssociation(Cascade.java:416) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
    at org.hibernate.engine.internal.Cascade.cascadeProperty(Cascade.java:218) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
    at org.hibernate.engine.internal.Cascade.cascade(Cascade.java:151) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
    at org.hibernate.event.internal.AbstractSaveEventListener.cascadeBeforeSave(AbstractSaveEventListener.java:427) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
    at org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:264) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
    at org.hibernate.event.internal.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:193) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
    at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:123) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
    at org.hibernate.event.internal.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:185) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
    at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:128) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
    at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:55) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
    at org.hibernate.event.service.internal.EventListenerGroupImpl.fireEventOnEachListener(EventListenerGroupImpl.java:102) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
    at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:721) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
    at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:707) ~[hibernate-core-5.4.21.Final.jar:5.4.21.Final]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_302]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_302]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_302]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_302]
    at org.springframework.orm.jpa.ExtendedEntityManagerCreator$ExtendedEntityManagerInvocationHandler.invoke(ExtendedEntityManagerCreator.java:366) ~[spring-orm-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at com.sun.proxy.$Proxy108.persist(Unknown Source) ~[na:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_302]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_302]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_302]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_302]
    at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:314) ~[spring-orm-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at com.sun.proxy.$Proxy108.persist(Unknown Source) ~[na:na]
    at org.springframework.data.jpa.repository.support.SimpleJpaRepository.save(SimpleJpaRepository.java:554) ~[spring-data-jpa-2.3.4.RELEASE.jar:2.3.4.RELEASE]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_302]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_302]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_302]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_302]
    at org.springframework.data.repository.core.support.ImplementationInvocationMetadata.invoke(ImplementationInvocationMetadata.java:72) ~[spring-data-commons-2.3.4.RELEASE.jar:2.3.4.RELEASE]
    at org.springframework.data.repository.core.support.RepositoryComposition$RepositoryFragments.invoke(RepositoryComposition.java:382) ~[spring-data-commons-2.3.4.RELEASE.jar:2.3.4.RELEASE]
    at org.springframework.data.repository.core.support.RepositoryComposition.invoke(RepositoryComposition.java:205) ~[spring-data-commons-2.3.4.RELEASE.jar:2.3.4.RELEASE]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$ImplementationMethodExecutionInterceptor.invoke(RepositoryFactorySupport.java:549) ~[spring-data-commons-2.3.4.RELEASE.jar:2.3.4.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.doInvoke(QueryExecutorMethodInterceptor.java:155) ~[spring-data-commons-2.3.4.RELEASE.jar:2.3.4.RELEASE]
    at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.invoke(QueryExecutorMethodInterceptor.java:130) ~[spring-data-commons-2.3.4.RELEASE.jar:2.3.4.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:80) ~[spring-data-commons-2.3.4.RELEASE.jar:2.3.4.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:367) ~[spring-tx-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:118) ~[spring-tx-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139) ~[spring-tx-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:178) ~[spring-data-jpa-2.3.4.RELEASE.jar:2.3.4.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:95) ~[spring-aop-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.data.repository.core.support.MethodInvocationValidator.invoke(MethodInvocationValidator.java:99) ~[spring-data-commons-2.3.4.RELEASE.jar:2.3.4.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212) ~[spring-aop-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at com.sun.proxy.$Proxy114.save(Unknown Source) ~[na:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_302]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_302]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_302]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_302]
    at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:344) ~[spring-aop-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:205) ~[spring-aop-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at com.sun.proxy.$Proxy79.save(Unknown Source) ~[na:na]
    at androidcourseapi.services.PetService.saveNewPet(PetService.kt:19) ~[main/:na]
    at androidcourseapi.controllers.PetsController.saveNewPet(PetsController.kt:20) ~[main/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_302]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_302]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_302]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_302]
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:878) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:792) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:652) ~[tomcat-embed-core-9.0.38.jar:4.0.FR]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) ~[tomcat-embed-core-9.0.38.jar:4.0.FR]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.38.jar:9.0.38]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.9.RELEASE.jar:5.2.9.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) [tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) [tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143) [tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) [tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374) [tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) [tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) [tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1590) [tomcat-embed-core-9.0.38.jar:9.0.38]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.38.jar:9.0.38]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_302]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_302]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.38.jar:9.0.38]
    at java.lang.Thread.run(Thread.java:748) [na:1.8.0_302]

实体是：

@Entity
@Table(name = "Pets")
data class Pet(
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    var id: Long = 0,
    var name: String = "",
    var age: Int = 0,
    var image: String = "",
    @OneToOne(cascade = [(CascadeType.ALL)], fetch = FetchType.EAGER)
    @JoinColumn(name = "type_id")
    var type: TypePet? = null,
    @OneToOne(cascade = [(CascadeType.ALL)], orphanRemoval = true, fetch = FetchType.EAGER)
    @JoinColumn(name = "status_id")
    var status: StatusPet? = null
)

@Entity
data class TypePet(
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    var id: Long = 0,
    var name: String = ""
)

@Entity
data class StatusPet(
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    var id: Long = 0,
    var name: String = ""
)

宠物控制器：

@RestController
@RequestMapping("/api/pets")
class PetsController(private val service: PetService) {

    @GetMapping
    fun getPets(): List<Pet> = service.getPets()

    @GetMapping("/{id}")
    fun getPetById(@PathVariable(value = "id") idPet: Long): ResponseEntity<Pet> =
        service.getPetById(idPet)

    @PostMapping
    fun saveNewPet(@RequestBody pet: Pet): ResponseEntity<Pet> = service.saveNewPet(pet)

    @PutMapping("/{id}")
    fun updatePetById(@PathVariable(value = "id") idPet: Long, @RequestBody newPet: Pet): ResponseEntity<Pet> =
        service.updatePet(idPet, newPet)

    @DeleteMapping("/{id}")
    fun deletePetById(@PathVariable(value = "id") idPet: Long): ResponseEntity<Unit> =
        service.deletePet(idPet)
}

存储库是：

@Repository
@Transactional(Transactional.TxType.MANDATORY)
interface PetsRepository : JpaRepository<Pet, Long>

服务：

@Service
class PetService(private val repository: PetsRepository) {

    fun getPets(): List<Pet> = repository.findAll().toList()

    fun getPetById(idPet: Long): ResponseEntity<Pet> =
        repository.findById(idPet).map {
            ResponseEntity.ok(it)
        }.orElse(ResponseEntity.notFound().build())

    fun saveNewPet(pet: Pet): ResponseEntity<Pet> =
        ResponseEntity.ok().body(repository.save(pet))

    fun updatePet(idPet: Long, newPet: Pet): ResponseEntity<Pet> =
        repository.findById(idPet).map {
            val updatedPet = it.copy(
                name = newPet.name,
                age = newPet.age,
                image = newPet.image,
                type = newPet.type,
                status = newPet.status
            )
            ResponseEntity.ok().body(repository.save(updatedPet))
        }.orElse(ResponseEntity.notFound().build())

    fun deletePet(idPet: Long): ResponseEntity<Unit> =
        repository.findById(idPet).map {
            ResponseEntity.ok().body(repository.delete(it))
        }.orElse(ResponseEntity.notFound().build())
}

正如我所说，我在数据库通信方面没有任何问题，因为我可以使用端点从表 Pets 中获取数据，问题是当我尝试保存或更新时，我'我不确定为什么会失败或如何解决它。我希望有人知道我为什么会收到此错误和/或如何解决它。

Answer 1

1. 为澄清实际问题，请告知我们您向保存 API 发送的请求正文。
2. 更一般地说，从软件架构的角度来看，我建议您在控制器层中为请求主体使用不同的类，而不是 JPA 实体类。 （我认为它会给你的程序带来很多问题） 我们称这些类主要用于控制器层 DTO 类。
3. 为了改进您的数据库建模，如果您只想保存类型名称和状态名称而没有任何信息（例如类型名称或状态名称的创建日期），我建议使用枚举类而不是 One-to-一实体。如果符合您的需要，您可以在 JPA 中使用 @Enumerated(EnumType.STRING) 注释。