Jpa Spring Boot“没有为这个类定义ID”

Question

在本课程中

@Entity
public class Journal  {

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String title;
private String content;

public Journal() {
}

public Journal(Long id, String title, String content) {
    this.id = id;
    this.title = title;
    this.content = content;
}

// getters and setters

@Override
public String toString() {
    return this.title+" | "+this.content;
}

我在公共类期刊行有一个错误没有为此实体层次结构定义ID。实体或IdClass类应该实现java.io.Serializable接口。，即使我实现java.io.Serializable接口，错误仍然存​​在。

运行简单的SpringApplication.run

时来自控制台的错误日志

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: No identifier specified for entity: com.example.Journal
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1628) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1081) ~[spring-context-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:856) ~[spring-context-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:542) ~[spring-context-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:737) [spring-boot-1.5.2.RELEASE.jar:1.5.2.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:370) [spring-boot-1.5.2.RELEASE.jar:1.5.2.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:314) [spring-boot-1.5.2.RELEASE.jar:1.5.2.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1162) [spring-boot-1.5.2.RELEASE.jar:1.5.2.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1151) [spring-boot-1.5.2.RELEASE.jar:1.5.2.RELEASE]
at com.example.JpaSpringApplication.main(JpaSpringApplication.java:12) [classes/:na]
Caused by: org.hibernate.AnnotationException: No identifier specified for entity: com.example.Journal
at org.hibernate.cfg.InheritanceState.determineDefaultAccessType(InheritanceState.java:265) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.cfg.InheritanceState.getElementsToProcess(InheritanceState.java:211) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.cfg.AnnotationBinder.bindClass(AnnotationBinder.java:717) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.boot.model.source.internal.annotations.AnnotationMetadataSourceProcessorImpl.processEntityHierarchies(AnnotationMetadataSourceProcessorImpl.java:245) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.boot.model.process.spi.MetadataBuildingProcess$1.processEntityHierarchies(MetadataBuildingProcess.java:222) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:265) ~[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-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:353) ~[spring-orm-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:370) ~[spring-orm-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:359) ~[spring-orm-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1687) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1624) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
... 15 common frames omitted