Spring Boot应用启动失败：Category实体缺少标识符问题

启动Spring Boot应用时出现启动失败，报错核心原因是com.codewithshivam.blog.entities.Category实体类未声明或继承@Id/@EmbeddedId标识符，导致entityManagerFactory Bean创建失败，修改端口无法解决该问题。

报错详情 #

2024-03-03T22:59:00.898+05:30  INFO 11404 --- [  restartedMain] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2024-03-03T22:59:00.913+05:30  INFO 11404 --- [  restartedMain] .s.b.a.l.ConditionEvaluationReportLogger : 

Error starting ApplicationContext. To display the condition evaluation report re-run your application with 'debug' enabled.
2024-03-03T22:59:00.943+05:30 ERROR 11404 --- [  restartedMain] o.s.boot.SpringApplication               : Application run failed

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Entity 'com.codewithshivam.blog.entities.Category' has no identifier (every '@Entity' class must declare or inherit at least one '@Id' or '@EmbeddedId' property)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1773) ~[spring-beans-6.1.3.jar:6.1.3]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:599) ~[spring-beans-6.1.3.jar:6.1.3]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:521) ~[spring-beans-6.1.3.jar:6.1.3]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:325) ~[spring-beans-6.1.3.jar:6.1.3]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-6.1.3.jar:6.1.3]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:323) ~[spring-beans-6.1.3.jar:6.1.3]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-6.1.3.jar:6.1.3]
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1231) ~[spring-context-6.1.3.jar:6.1.3]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:949) ~[spring-context-6.1.3.jar:6.1.3]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:624) ~[spring-context-6.1.3.jar:6.1.3]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:146) ~[spring-boot-3.2.2.jar:3.2.2]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:754) ~[spring-boot-3.2.2.jar:3.2.2]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:456) ~[spring-boot-3.2.2.jar:3.2.2]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:334) ~[spring-boot-3.2.2.jar:3.2.2]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1354) ~[spring-boot-3.2.2.jar:3.2.2]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1343) ~[spring-boot-3.2.2.jar:3.2.2]
    at com.codewithshivam.blog.BlogAppApisApplication.main(BlogAppApisApplication.java:12) ~[classes/:na]
    at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103) ~[na:na]
    at java.base/java.lang.reflect.Method.invoke(Method.java:580) ~[na:na]
    at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:50) ~[spring-boot-devtools-3.2.2.jar:3.2.2]
Caused by: org.hibernate.AnnotationException: Entity 'com.codewithshivam.blog.entities.Category' has no identifier (every '@Entity' class must declare or inherit at least one '@Id' or '@EmbeddedId' property)
    at org.hibernate.boot.model.internal.InheritanceState.determineDefaultAccessType(InheritanceState.java:279) ~[hibernate-core-6.4.1.Final.jar:6.4.1.Final]
    at org.hibernate.boot.model.internal.InheritanceState.getElementsToProcess(InheritanceState.java:215) ~[hibernate-core-6.4.1.Final.jar:6.4.1.Final]
    at org.hibernate.boot.model.internal.InheritanceState.postProcess(InheritanceState.java:160) ~[hibernate-core-6.4.1.Final.jar:6.4.1.Final]
    at org.hibernate.boot.model.internal.EntityBinder.handleIdentifier(EntityBinder.java:345) ~[hibernate-core-6.4.1.Final.jar:6.4.1.Final]
    at org.hibernate.boot.model.internal.EntityBinder.bindEntityClass(EntityBinder.java:234) ~[hibernate-core-6.4.1.Final.jar:6.4.1.Final]
    at org.hibernate.boot.model.internal.AnnotationBinder.bindClass(AnnotationBinder.java:423) ~[hibernate-core-6.4.1.Final.jar:6.4.1.Final]
    at org.hibernate.boot.model.source.internal.annotations.AnnotationMetadataSourceProcessorImpl.processEntityHierarchies(AnnotationMetadataSourceProcessorImpl.java:256) ~[hibernate-core-6.4.1.Final.jar:6.4.1.Final]
    at org.hibernate.boot.model.process.spi.MetadataBuildingProcess$1.processEntityHierarchies(MetadataBuildingProcess.java:279) ~[hibernate-core-6.4.1.Final.jar:6.4.1.Final]
    at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:322) ~[hibernate-core-6.4.1.Final.jar:6.4.1.Final]
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:1432) ~[hibernate-core-6.4.1.Final.jar:6.4.1.Final]
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:1503) ~[hibernate-core-6.4.1.Final.jar:6.4.1.Final]
    at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:75) ~[spring-orm-6.1.3.jar:6.1.3]
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:376) ~[spring-orm-6.1.3.jar:6.1.3]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:409) ~[spring-orm-6.1.3.jar:6.1.3]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:396) ~[spring-orm-6.1.3.jar:6.1.3]
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.afterPropertiesSet(LocalContainerEntityManagerFactoryBean.java:352) ~[spring-orm-6.1.3.jar:6.1.3]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1820) ~[spring-beans-6.1.3.jar:6.1.3]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1769) ~[spring-beans-6.1.3.jar:6.1.3]
    ... 19 common frames omitted


Process finished with exit code 0

解决方案 #

• 添加主键标识符：在Category实体类的主键字段上添加@Id注解，若需要自动生成主键，可搭配@GeneratedValue指定生成策略，示例代码：

import jakarta.persistence.Entity;
import jakarta.persistence.Id;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;

@Entity
public class Category {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY) // 自增策略，可根据需求调整
    private Long id;
    
    // 其他业务字段、getter、setter方法
}

• 复合主键处理：如果使用复合主键，可通过@EmbeddedId注解嵌入主键类，或使用@IdClass注解指定主键类
• 检查注解导入：Spring Boot 3及以上版本需导入jakarta.persistence包下的注解，而非旧版javax.persistence
• 继承场景检查：若Category继承自基类，确认基类中已声明@Id且子类正确继承

内容的提问来源于stack exchange，提问作者Shivam