报错 org.hibernate.AnnotationException: No identifier specified for entity:

场景：在springboot整合springdata jpa时抛出错误

Caused by: org.hibernate.AnnotationException: No identifier specified for entity: com.csii.wgc.entity.User
    at org.hibernate.cfg.InheritanceState.determineDefaultAccessType(InheritanceState.java:266) ~[hibernate-core-5.2.16.Final.jar:5.2.16.Final]
    at org.hibernate.cfg.InheritanceState.getElementsToProcess(InheritanceState.java:211) ~[hibernate-core-5.2.16.Final.jar:5.2.16.Final]
    at org.hibernate.cfg.AnnotationBinder.bindClass(AnnotationBinder.java:730) ~[hibernate-core-5.2.16.Final.jar:5.2.16.Final]
    at org.hibernate.boot.model.source.internal.annotations.AnnotationMetadataSourceProcessorImpl.processEntityHierarchies(AnnotationMetadataSourceProcessorImpl.java:249) ~[hibernate-core-5.2.16.Final.jar:5.2.16.Final]
    at org.hibernate.boot.model.process.spi.MetadataBuildingProcess$1.processEntityHierarchies(MetadataBuildingProcess.java:222) ~[hibernate-core-5.2.16.Final.jar:5.2.16.Final]
    at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:265) ~[hibernate-core-5.2.16.Final.jar:5.2.16.Final]
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:861) ~[hibernate-core-5.2.16.Final.jar:5.2.16.Final]
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:888) ~[hibernate-core-5.2.16.Final.jar:5.2.16.Final]
    at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:57) ~[spring-orm-5.0.5.RELEASE.jar:5.0.5.RELEASE]

解决：

①在实体类的主键上加上@Id主键 

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

②查看注解是否引入错误

@Id 注解的包不是 org.springframework.data.annotation.Id 而是 javax.persistence.Id