如何使用findBy方法

這是我的主表 @Entity（name = 「EnumMaster」）公共類EnumMaster { @Id @ org.hibernate.annotations.Type（TYPE = 「PG-UUID」） private UUID EnumerationID; 私人字符串名稱; private String Text; 私人字符串描述;如何使用findBy方法

public EnumMaster(String parentId) { 

     this.Name=parentId; 
    } 
getter setter 
}

此表中包含其值

Entity(name = "EnumValue") 
public class EnumValue { 

    @Id 
    @org.hibernate.annotations.Type(type="pg-uuid") 
    private UUID EnumValueID; 
    @ManyToOne 
    private EnumMaster enumMaster; 
    private String Name; 
    private String Text; 
    private String Description; 
    setter getters 
}

控制器

@RequestMapping(value="/retrivefromPublicationDropDown",method=RequestMethod.GET,produces="application/json") 
public @ResponseBody 
    ArrayList getPublicationStatus(NativeWebRequest req){ 
     ArrayList<EnumValue> arrayList=new ArrayList<EnumValue>(); 
     try{ 
      **String parentID="ePublicationStatus"; 
      Collection<EnumValue> list=dropDownService.findByEnumMaster(parentID);** 
      arrayList=this.populateStatus(list); 

     } 
     catch (Exception e) { 
      logger.error(" *** Get Brands by partner ID", e); 
     } 
     return arrayList; 

} 

private ArrayList<EnumValue> populateStatus(Collection<EnumValue> list) { 
    ArrayList<EnumValue>eval= new ArrayList<EnumValue>(); 
    for(EnumValue ev:list){ 
     eval.add(ev); 
    } 
    return eval; 
}

服務

public Collection<EnumValue> findByEnumMaster(String parentId) { 

     return dropDownRepository.findByEnumMaster(new EnumMaster(parentId)); 
    }

什麼其實我想要做的是在通過名稱來獲取值EnumMaster和ge t爲值所以，我怎麼可以使用findBy方法，因爲現在它給我的錯誤

錯誤： -

org.springframework.dao.InvalidDataAccessApiUsageException: org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: com.dts.adminportal.dto.EnumMaster; nested exception is java.lang.IllegalStateException: org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: com.dts.adminportal.dto.EnumMaster 
    at org.springframework.orm.jpa.EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(EntityManagerFactoryUtils.java:298) ~[spring-orm-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:106) ~[spring-orm-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.translateExceptionIfPossible(AbstractEntityManagerFactoryBean.java:403) ~[spring-orm-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible(ChainedPersistenceExceptionTranslator.java:58) ~[spring-tx-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at org.springframework.dao.support.DataAccessUtils.translateIfNecessary(DataAccessUtils.java:213) ~[spring-tx-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:163) ~[spring-tx-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) ~[spring-aop-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at org.springframework.data.jpa.repository.support.LockModeRepositoryPostProcessor$LockModePopulatingMethodIntercceptor.invoke(LockModeRepositoryPostProcessor.java:92) ~[spring-data-jpa-1.3.0.RELEASE.jar:na] 
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) ~[spring-aop-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:90) ~[spring-aop-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) ~[spring-aop-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202) ~[spring-aop-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at com.sun.proxy.$Proxy81.findByEnumMaster(Unknown Source) ~[na:na] 
    at com.dts.adminportal.service.DropDownServiceImpl.findByEnumMaster(DropDownServiceImpl.java:31) ~[classes/:na] 
    at com.dts.adminportal.controller.DropDownController.getPublicationStatus(DropDownController.java:35) ~[classes/:na] 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.7.0_45] 
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.7.0_45] 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.7.0_45] 
    at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.7.0_45] 
    at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:213) [spring-web-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:126) [spring-web-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:96) [spring-webmvc-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:617) [spring-webmvc-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:578) [spring-webmvc-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80) [spring-webmvc-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:923) [spring-webmvc-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852) [spring-webmvc-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882) [spring-webmvc-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:778) [spring-webmvc-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:617) [servlet-api-6.0.29.jar:na] 
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) [servlet-api-6.0.29.jar:na] 
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) [catalina-6.0.29.jar:6.0.29] 
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) [catalina-6.0.29.jar:6.0.29] 
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) [catalina-6.0.29.jar:6.0.29] 
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) [catalina-6.0.29.jar:6.0.29] 
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) [catalina-6.0.29.jar:6.0.29] 
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) [catalina-6.0.29.jar:6.0.29] 
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) [catalina-6.0.29.jar:6.0.29] 
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298) [catalina-6.0.29.jar:6.0.29] 
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:857) [coyote-6.0.29.jar:6.0.29] 
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588) [coyote-6.0.29.jar:6.0.29] 
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489) [coyote-6.0.29.jar:6.0.29] 
    at java.lang.Thread.run(Unknown Source) [na:1.7.0_45] 
Caused by: java.lang.IllegalStateException: org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: com.dts.adminportal.dto.EnumMaster 
    at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1211) ~[hibernate-entitymanager-3.6.3.Final.jar:3.6.3.Final] 
    at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1147) ~[hibernate-entitymanager-3.6.3.Final.jar:3.6.3.Final] 
    at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:255) ~[hibernate-entitymanager-3.6.3.Final.jar:3.6.3.Final] 
    at org.hibernate.ejb.criteria.CriteriaQueryCompiler$3.getResultList(CriteriaQueryCompiler.java:260) ~[hibernate-entitymanager-3.6.3.Final.jar:3.6.3.Final] 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.7.0_45] 
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.7.0_45] 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.7.0_45] 
    at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.7.0_45] 
    at org.springframework.orm.jpa.SharedEntityManagerCreator$DeferredQueryInvocationHandler.invoke(SharedEntityManagerCreator.java:310) ~[spring-orm-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at com.sun.proxy.$Proxy95.getResultList(Unknown Source) ~[na:na] 
    at org.springframework.data.jpa.repository.query.JpaQueryExecution$CollectionExecution.doExecute(JpaQueryExecution.java:77) ~[spring-data-jpa-1.3.0.RELEASE.jar:na] 
    at org.springframework.data.jpa.repository.query.JpaQueryExecution.execute(JpaQueryExecution.java:55) ~[spring-data-jpa-1.3.0.RELEASE.jar:na] 
    at org.springframework.data.jpa.repository.query.AbstractJpaQuery.doExecute(AbstractJpaQuery.java:95) ~[spring-data-jpa-1.3.0.RELEASE.jar:na] 
    at org.springframework.data.jpa.repository.query.AbstractJpaQuery.execute(AbstractJpaQuery.java:85) ~[spring-data-jpa-1.3.0.RELEASE.jar:na] 
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:312) ~[spring-data-commons-1.5.0.RELEASE.jar:na] 
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) ~[spring-aop-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110) ~[spring-tx-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) ~[spring-aop-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:155) ~[spring-tx-3.1.2.RELEASE.jar:3.1.2.RELEASE] 
    ... 37 common frames omitted 
Caused by: org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: com.dts.adminportal.dto.EnumMaster 
    at org.hibernate.engine.ForeignKeys.getEntityIdentifierIfNotUnsaved(ForeignKeys.java:243) ~[hibernate-core-3.6.3.Final.jar:3.6.3.Final] 
    at org.hibernate.type.EntityType.getIdentifier(EntityType.java:456) ~[hibernate-core-3.6.3.Final.jar:3.6.3.Final] 
    at org.hibernate.type.ManyToOneType.nullSafeSet(ManyToOneType.java:130) ~[hibernate-core-3.6.3.Final.jar:3.6.3.Final] 
    at org.hibernate.param.NamedParameterSpecification.bind(NamedParameterSpecification.java:67) ~[hibernate-core-3.6.3.Final.jar:3.6.3.Final] 
    at org.hibernate.loader.hql.QueryLoader.bindParameterValues(QueryLoader.java:571) ~[hibernate-core-3.6.3.Final.jar:3.6.3.Final] 
    at org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1716) ~[hibernate-core-3.6.3.Final.jar:3.6.3.Final] 
    at org.hibernate.loader.Loader.doQuery(Loader.java:801) ~[hibernate-core-3.6.3.Final.jar:3.6.3.Final] 
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:274) ~[hibernate-core-3.6.3.Final.jar:3.6.3.Final] 
    at org.hibernate.loader.Loader.doList(Loader.java:2533) ~[hibernate-core-3.6.3.Final.jar:3.6.3.Final] 
    at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2276) ~[hibernate-core-3.6.3.Final.jar:3.6.3.Final] 
    at org.hibernate.loader.Loader.list(Loader.java:2271) ~[hibernate-core-3.6.3.Final.jar:3.6.3.Final] 
    at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:452) ~[hibernate-core-3.6.3.Final.jar:3.6.3.Final] 
    at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:363) ~[hibernate-core-3.6.3.Final.jar:3.6.3.Final] 
    at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:196) ~[hibernate-core-3.6.3.Final.jar:3.6.3.Final] 
    at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1268) ~[hibernate-core-3.6.3.Final.jar:3.6.3.Final] 
    at org.hibernate.impl.QueryImpl.list(QueryImpl.java:102) ~[hibernate-core-3.6.3.Final.jar:3.6.3.Final] 
    at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:246) ~[hibernate-entitymanager-3.6.3.Final.jar:3.6.3.Final] 
    ... 53 common frames omitted

來源

2014-03-29 Sumeet

你findByEnumMaster方法需要EnumValueMaster，因爲它的參數，而不是字符串（這是它的id）。

這個事實可以在this教程

來源

2014-03-29 07:16:49 geoand

Thnaks可以看出但是現在可以ü請幫助我解決這個錯誤 – Sumeet

看來你試圖保存EnumValue在它未保存EnumMaster。您在EnumValue中設置的EnumMaster需要是數據庫中的一個託管實體，從存儲庫中檢索（或者，如果它是一個新值，則需要保存並將保存的值設置爲EnumValue） – geoand

如何使用findBy方法

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