Problem with Hibernate: can't add new entity when the parent isn't already existing

Jens De Dycker 0
Viewed 41

I'm trying to make a library app, I have a oneToMany relationship between book and Author however I am running into trouble whenever I try to add a new book for an Author that isn't registered yet. Whenever i Try to register a book for an existing everything works fine.

Here is my code:

@Entity
@Getter
@Setter
public class Book {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    @NotBlank
    private String title;

    @ManyToOne
    private Author author;

    private boolean beschikbaar = true;

@Getter
@Setter
public class Author {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
@NotBlank
    private String voornaam;
@NotBlank
    private String familienaam;

@OneToMany(mappedBy = "author", cascade = CascadeType.ALL,orphanRemoval = true)
    private Set<Book> repertoire;
}

Controller:

    public String newBookView(Model model) {
        model.addAttribute("book", new Book());
        model.addAttribute("auteur", new Author());
        return "boekToevoegen";
    }


        @PostMapping("/books/new")
        public String addNewBook(@Valid Book book, @Valid Author author, BindingResult br)
        {
            Optional<Author> mogelijksNieuweAuteur = authorService.findAuthorByVoornaamAndFamilienaam(author.getVoornaam(),author.getFamilienaam());

            if(mogelijksNieuweAuteur.isPresent() && !br.hasErrors())
            {
                Author bestaandeAuteur = mogelijksNieuweAuteur.get();
                book.setAuthor(bestaandeAuteur);
                bookService.register(book);
                return "redirect:/books";

            } else if (!br.hasErrors()) {

                book.setAuthor(author);
                bookService.register(book);
                return "redirect:/books";
            }

            else
            {
                return "boekToevoegen";
            }

View:


  <div class="col-2">
    <label for="title" class="form-label">Titel</label>
    <input type="text" class="form-control required" id="title" th:field="${book.title}">
  </div>
  <div class="row" >
   <div class="col-3">
    <label for="auteurVoornaam" class="form-label">Voornaam auteur </label>
    <input type="text" class="form-control" id="auteurVoornaam" th:field="${auteur.voornaam}">
</div>
    <div class="col-3">
     <label for="auteurFamilienaam" class="form-label">familienaam auteur </label>
     <input type="text" class="form-control" id="auteurFamilienaam" th:field="${auteur.familienaam}">
   </div>
  </div>
  <button type="submit" class="button btn-primary"> Save </button>
</form>

Repo and corresponding servicefunction:


@Repository
public interface AuthorRepository extends JpaRepository<Author,Long> {

@Query(nativeQuery = true,value= "select * from author where voornaam = :voornaam and familienaam = :familienaam")
    Optional <Author> findByVoornaamAndFamilienaam(@Param(value = "voornaam") String voornaam, @Param(value="familienaam") String familienaam);
  public Optional<Author> findAuthorByVoornaamAndFamilienaam(String voornaam, String familienaam)
    {
        Optional <Author> gezochteAuteur = Optional.of(new Author());
        if(authorRepository.findByVoornaamAndFamilienaam(voornaam,familienaam).isPresent())
        {
            gezochteAuteur=  authorRepository.findByVoornaamAndFamilienaam(voornaam,familienaam);
        }

        return gezochteAuteur;
    }

Thanks in advance!

EDIT: Here is my errorpage

There was an unexpected error (type=Internal Server Error, status=500).
org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing : be.jeeeens.klasbib.entities.Book.author -> be.jeeeens.klasbib.entities.Author; nested exception is java.lang.IllegalStateException: org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing : be.jeeeens.klasbib.entities.Book.author -> be.jeeeens.klasbib.entities.Author
org.springframework.dao.InvalidDataAccessApiUsageException: org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing : be.jeeeens.klasbib.entities.Book.author -> be.jeeeens.klasbib.entities.Author; nested exception is java.lang.IllegalStateException: org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing : be.jeeeens.klasbib.entities.Book.author -> be.jeeeens.klasbib.entities.Author
    at org.springframework.orm.jpa.EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(EntityManagerFactoryUtils.java:371)
    at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:235)
    at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:566)
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:743)
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:711)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:654)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:407)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:119)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:137)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
    at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:174)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:97)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:215)
    at com.sun.proxy.$Proxy111.save(Unknown Source)
    at be.jeeeens.klasbib.service.BookServiceImpl.register(BookServiceImpl.java:23)
    at be.jeeeens.klasbib.model.BookController.addNewBook(BookController.java:54)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1070)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:681)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:764)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:360)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:399)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:890)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1789)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
    at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.lang.IllegalStateException: org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing : be.jeeeens.klasbib.entities.Book.author -> be.jeeeens.klasbib.entities.Author
    at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:151)
    at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:181)
    at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:188)
    at org.hibernate.internal.SessionImpl.doFlush(SessionImpl.java:1411)
    at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:489)
    at org.hibernate.internal.SessionImpl.flushBeforeTransactionCompletion(SessionImpl.java:3290)
    at org.hibernate.internal.SessionImpl.beforeTransactionCompletion(SessionImpl.java:2425)
    at org.hibernate.engine.jdbc.internal.JdbcCoordinatorImpl.beforeTransactionCompletion(JdbcCoordinatorImpl.java:449)
    at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.beforeCompletionCallback(JdbcResourceLocalTransactionCoordinatorImpl.java:183)
    at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.access$300(JdbcResourceLocalTransactionCoordinatorImpl.java:40)
    at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.commit(JdbcResourceLocalTransactionCoordinatorImpl.java:281)
    at org.hibernate.engine.transaction.internal.TransactionImpl.commit(TransactionImpl.java:101)
    at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:562)
    ... 66 more
Caused by: org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing : be.jeeeens.klasbib.entities.Book.author -> be.jeeeens.klasbib.entities.Author
    at org.hibernate.engine.spi.CascadingActions$8.noCascade(CascadingActions.java:379)
    at org.hibernate.engine.internal.Cascade.cascade(Cascade.java:169)
    at org.hibernate.event.internal.AbstractFlushingEventListener.cascadeOnFlush(AbstractFlushingEventListener.java:159)
    at org.hibernate.event.internal.AbstractFlushingEventListener.prepareEntityFlushes(AbstractFlushingEventListener.java:149)
    at org.hibernate.event.internal.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:82)
    at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:39)
    at org.hibernate.event.service.internal.EventListenerGroupImpl.fireEventOnEachListener(EventListenerGroupImpl.java:107)
    at org.hibernate.internal.SessionImpl.doFlush(SessionImpl.java:1407)
    ... 75 more
spring hibernate java
2 Answers

Hibernate CascadeType.ALL strategy includes the CascadeType.PERSIST option, when calling persist entity, Hibernate is going to persist both the Author and the Books child entities. Your code should look something like below. Where, you will persist the author object and hibernate will take care of persisting the children,

Author bestaandeAuteur = mogelijksNieuweAuteur.get();
Set<Book> books = new HashSet<Book>();
books.add(book);
bestaandeAuteur.setRepertoire(books);
authorService.persist(bestaandeAuteur);
Sreek5210

Ensure you set author into the book entity as well as adding a book to author. Then call save author. If you try and save book there is no cascade from book to author

johnnyutts0
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