我尝试将 Observable 及其观察者存储到数据库中。我在执行期间收到
org.hibernate.AnnotationException: mappedBy reference an unknown target entity property
当然，我使用谷歌并找到了一些很好的答案。
所以我添加了注解mappedBy、targetEntity、fetch和cascade。
但我仍然遇到同样的错误。到目前为止，我实际上已经尝试了通过谷歌可以找到的所有内容，但没有成功。这可能只是一个小想法，我希望你能帮助我。 (我使用Spring Boot)
ObservableImpl
@Entity
public class ObservableImpl extends Observable {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String name;
@OneToMany(mappedBy = "oservableImpl", targetEntity = ObserverImpl.class, cascade = CascadeType.ALL, fetch = FetchType.LAZY)
List<ObserverImpl> observerList = new LinkedList<>();
public ObservableImpl(String name) {
this.name = name;
}
protected ObservableImpl() {
}
@Override
public synchronized void addObserver(Observer o) {
super.addObserver(o);
observerList.add((ObserverImpl) o);
}
@Override
public synchronized void deleteObserver(Observer o) {
super.deleteObserver(o);
observerList.remove(o);
}
public void change() {
setChanged();
notifyObservers();
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
ObservableImpl that = (ObservableImpl) o;
return id == that.id;
}
@Override
public String toString() {
return "ObservableImpl{" +
"ID=" + id +
'}';
}
}
ObserverImpl
@Entity
public class ObserverImpl implements Observer {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long ID;
private String name;
public Long getID() {
return ID;
}
public void setID(Long ID) {
this.ID = ID;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public ObserverImpl(String name) {
this.name = name;
}
protected ObserverImpl() {
}
@Override
public String toString() {
return "ObserverImpl{" +
"ID=" + ID +
'}';
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
ObserverImpl observer = (ObserverImpl) o;
return ID == observer.ID;
}
@Override
public void update(Observable o, Object arg) {
System.out.println(this);
}
}
错误消息:
2017-06-11 14:40:57.032 INFO 21156 --- [ main] c.e.hibernate.HibernateApplication : No active profile set, falling back to default profiles: default
2017-06-11 14:40:57.061 INFO 21156 --- [ main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@4516af24: startup date [Sun Jun 11 14:40:57 CEST 2017]; root of context hierarchy
2017-06-11 14:40:57.826 INFO 21156 --- [ main] trationDelegate$BeanPostProcessorChecker : Bean 'org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration' of type [org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration$$EnhancerBySpringCGLIB$$cfcf04d] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2017-06-11 14:40:58.032 INFO 21156 --- [ main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)
2017-06-11 14:40:58.039 INFO 21156 --- [ main] o.apache.catalina.core.StandardService : Starting service Tomcat
2017-06-11 14:40:58.039 INFO 21156 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet Engine: Apache Tomcat/8.5.14
2017-06-11 14:40:58.091 INFO 21156 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2017-06-11 14:40:58.091 INFO 21156 --- [ost-startStop-1] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 1031 ms
2017-06-11 14:40:58.163 INFO 21156 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean : Mapping servlet: 'dispatcherServlet' to [/]
2017-06-11 14:40:58.165 INFO 21156 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'characterEncodingFilter' to: [/*]
2017-06-11 14:40:58.166 INFO 21156 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2017-06-11 14:40:58.166 INFO 21156 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2017-06-11 14:40:58.166 INFO 21156 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'requestContextFilter' to: [/*]
2017-06-11 14:40:58.387 INFO 21156 --- [ main] j.LocalContainerEntityManagerFactoryBean : Building JPA container EntityManagerFactory for persistence unit 'default'
2017-06-11 14:40:58.394 INFO 21156 --- [ main] o.hibernate.jpa.internal.util.LogHelper : HHH000204: Processing PersistenceUnitInfo [
name: default
...]
2017-06-11 14:40:58.428 INFO 21156 --- [ main] org.hibernate.Version : HHH000412: Hibernate Core {5.0.12.Final}
2017-06-11 14:40:58.428 INFO 21156 --- [ main] org.hibernate.cfg.Environment : HHH000206: hibernate.properties not found
2017-06-11 14:40:58.429 INFO 21156 --- [ main] org.hibernate.cfg.Environment : HHH000021: Bytecode provider name : javassist
2017-06-11 14:40:58.449 INFO 21156 --- [ main] o.hibernate.annotations.common.Version : HCANN000001: Hibernate Commons Annotations {5.0.1.Final}
2017-06-11 14:40:58.501 INFO 21156 --- [ main] org.hibernate.dialect.Dialect : HHH000400: Using dialect: org.hibernate.dialect.H2Dialect
2017-06-11 14:40:58.596 WARN 21156 --- [ main] ationConfigEmbeddedWebApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaAutoConfiguration.class]: Invocation of init method failed; nested exception is org.hibernate.AnnotationException: mappedBy reference an unknown target entity property: com.example.hibernate.obs.ObserverImpl.oservableImpl in com.example.hibernate.obs.ObservableImpl.observerList
2017-06-11 14:40:58.598 INFO 21156 --- [ main] o.apache.catalina.core.StandardService : Stopping service Tomcat
2017-06-11 14:40:58.606 INFO 21156 --- [ main] utoConfigurationReportLoggingInitializer :
Error starting ApplicationContext. To display the auto-configuration report re-run your application with 'debug' enabled.
2017-06-11 14:40:58.612 ERROR 21156 --- [ main] o.s.boot.SpringApplication : Application startup failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaAutoConfiguration.class]: Invocation of init method failed; nested exception is org.hibernate.AnnotationException: mappedBy reference an unknown target entity property: com.example.hibernate.obs.ObserverImpl.oservableImpl in com.example.hibernate.obs.ObservableImpl.observerList
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1628) ~[spring-beans-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555) ~[spring-beans-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1081) ~[spring-context-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:856) ~[spring-context-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:542) ~[spring-context-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[spring-boot-1.5.3.RELEASE.jar:1.5.3.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:737) [spring-boot-1.5.3.RELEASE.jar:1.5.3.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:370) [spring-boot-1.5.3.RELEASE.jar:1.5.3.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:314) [spring-boot-1.5.3.RELEASE.jar:1.5.3.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1162) [spring-boot-1.5.3.RELEASE.jar:1.5.3.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1151) [spring-boot-1.5.3.RELEASE.jar:1.5.3.RELEASE]
at com.example.hibernate.HibernateApplication.main(HibernateApplication.java:19) [classes/:na]
Caused by: org.hibernate.AnnotationException: mappedBy reference an unknown target entity property: com.example.hibernate.obs.ObserverImpl.oservableImpl in com.example.hibernate.obs.ObservableImpl.observerList
at org.hibernate.cfg.annotations.CollectionBinder.bindStarToManySecondPass(CollectionBinder.java:769) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.cfg.annotations.CollectionBinder$1.secondPass(CollectionBinder.java:719) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.cfg.CollectionSecondPass.doSecondPass(CollectionSecondPass.java:54) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses(InFlightMetadataCollectorImpl.java:1655) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses(InFlightMetadataCollectorImpl.java:1623) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:278) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:847) ~[hibernate-entitymanager-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:874) ~[hibernate-entitymanager-5.0.12.Final.jar:5.0.12.Final]
at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:60) ~[spring-orm-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:353) ~[spring-orm-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:370) ~[spring-orm-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:359) ~[spring-orm-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1687) ~[spring-beans-4.3.8.RELEASE.jar:4.3.8.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1624) ~[spring-beans-4.3.8.RELEASE.jar:4.3.8.RELEASE]
... 16 common frames omitted
Process finished with exit code 1
非常感谢。
HibernateApplication
@SpringBootApplication
public class HibernateApplication {
private static final Logger log = LoggerFactory.getLogger(HibernateApplication.class);
public static void main(String[] args) {
SpringApplication.run(HibernateApplication.class);
}
@Bean
public CommandLineRunner addObservables(ObserveableRepository repository) {
return (args) -> {
useObserver(repository);
// fetch all customers
log.info("Observables found with findAll():");
log.info("-------------------------------");
for (ObservableImpl observable : repository.findAll()) {
log.info(observable.toString());
observable.change();
}
log.info("");
};
}
private void useObserver(ObserveableRepository repository) {
ObservableImpl observable = new ObservableImpl("1");
observable.addObserver(new ObserverImpl("firstObserver"));
observable.addObserver(new ObserverImpl("secondObserver"));
observable.addObserver(new ObserverImpl("thirdObserver"));
repository.save(observable);
}
}
ObservableRepository
public interface ObserveableRepository extends CrudRepository<ObservableImpl, Long> {
}
application.properties
spring.datasource.url=jdbc:h2:file:~/test3;DB_CLOSE_ON_EXIT=FALSE;AUTO_RECONNECT=TRUE
spring.datasource.username=admin
spring.datasource.password=password
spring.datasource.driver-class-name=org.h2.Driver
spring.jpa.show-sql=true
spring.jpa.hibernate.ddl-auto=update
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.H2Dialect
最佳答案
我建议您重命名您的实体并给它们提供“简单”且易于理解的名称。这将使您不必关心其字段的复杂定义和可能的错误。
例如:
@Entity
public class Experiment extends Observable {
//...
@OneToMany(mappedBy = "experiment")
private Set<Experimenter> experimenters = new HashSet<>();
//...
}
@Entity
public class Experimenter extends Observer {
//...
@ManyToOne
private Experiment experiment;
//...
}
所以我们这里有一个经典的双向 OneToMany association
<小时/>要从 IDE 访问 H2 数据库，您可以使用 this回答。
关于java - 映射通过引用带有注释的未知目标实体属性，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/44483712/