java - spring jpa中根据实体从多个表中获取数据

标签 java spring spring-boot jpa spring-data-jpa

我有如下三个实体:

评论:

@Entity
@Table(name = "comments")
public class CommentBean implements Serializable {

    @Id
    @Column(name = "id")
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @Column(name = "commentId")
    private long commentId;

    @Column(name = "topicId")
    private String topicId;
}

主题:

@Entity
@Table(name = "topics")
public class TopicBean implements Serializable {

    @Id
    @Column(name = "id")
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @Column(name = "topicId")
    private String topicId;
    @Column(name = "title")
    private String title;
    @Column(name = "details")
    private String details;
    @Column(name = "username")
    private String username;
    @Column(name = "userImage")
    private String userImage;
    @Column(name = "dayPosted")
    private String dayPosted;
}

喜欢:

@Entity
@Table(name = "comment_likes")
public class CommentLikes implements Serializable {

    @Id
    @Column(name = "id")
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @Column(name = "commentLikes")
    private String commentLikes;

    @Column(name = "commentId")
    private long commentId;
}

我想根据请求获取三个表/实体的所有数据:

@RequestMapping(path = "/get_data_on_login", method = RequestMethod.GET)
public ResponseEntity get_data_on_login()) throws Exception {

}

我该如何实现这一目标？我已经看到使用 @query 的示例和一些使用 searchByAnd... 的示例，但遵循哪种方法更令人困惑。

更新:

尝试使用 @JoinColumn 映射表以使用 bean.findAll() 获取数据，但是，我收到此错误:

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 javax.persistence.PersistenceException: [PersistenceUnit: default] Unable to build Hibernate SessionFactory
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1589) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:554) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1081) ~[spring-context-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:856) ~[spring-context-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:542) ~[spring-context-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:761) [spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:371) [spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) [spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1186) [spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1175) [spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE]
    at seconds47.Application.main(Application.java:24) [classes/:?]
Caused by: javax.persistence.PersistenceException: [PersistenceUnit: default] Unable to build Hibernate SessionFactory
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.persistenceException(EntityManagerFactoryBuilderImpl.java:954) ~[hibernate-entitymanager-5.0.11.Final.jar:5.0.11.Final]
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:882) ~[hibernate-entitymanager-5.0.11.Final.jar:5.0.11.Final]
    at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:60) ~[spring-orm-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:353) ~[spring-orm-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:373) ~[spring-orm-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:362) ~[spring-orm-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1648) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1585) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    ... 16 more
Caused by: org.hibernate.MappingException: Repeated column in mapping for entity: seconds47.beans.CommentBean column: topicId (should be mapped with insert="false" update="false")
    at org.hibernate.mapping.PersistentClass.checkColumnDuplication(PersistentClass.java:830) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
    at org.hibernate.mapping.PersistentClass.checkPropertyColumnDuplication(PersistentClass.java:848) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
    at org.hibernate.mapping.PersistentClass.checkColumnDuplication(PersistentClass.java:870) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
    at org.hibernate.mapping.PersistentClass.validate(PersistentClass.java:605) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
    at org.hibernate.mapping.RootClass.validate(RootClass.java:265) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
    at org.hibernate.boot.internal.MetadataImpl.validate(MetadataImpl.java:329) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
    at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:443) ~[hibernate-core-5.0.11.Final.jar:5.0.11.Final]
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:879) ~[hibernate-entitymanager-5.0.11.Final.jar:5.0.11.Final]
    at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:60) ~[spring-orm-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:353) ~[spring-orm-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:373) ~[spring-orm-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:362) ~[spring-orm-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1648) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1585) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    ... 16 more

更新代码:

主题 bean :

@Entity
@Table(name = "topics")
public class TopicBean implements Serializable {

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

    @Column(name = "topicId")
    private String topicId;
    @Column(name = "title")
    private String title;
    @Column(name = "details")
    private String details;
    @Column(name = "username")
    private String username;
    @Column(name = "userImage")
    private String userImage;
    @Column(name = "dayPosted")
    private String dayPosted;

    @OneToMany(mappedBy="topicBean")
    private List<CommentBean> commentBeans;
}

评论Bean:

@Entity
@Table(name = "comments")
public class CommentBean implements Serializable {

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

    @Column(name = "commentId")
    private long commentId;

    @Column(name = "topicId")
    private String topicId;

    @Column(name = "comments")
    private String comments;

    @Column(name = "commentDate")
    private String commentDate;

    @Column(name = "userImage")
    private String userImage;

    @Column(name = "username")
    private String username;

    @ManyToOne
    @JoinColumn(name="topicId")
    private TopicBean topicBean;
}

存储库:

评论喜欢 repo :

@Repository
public interface CommentLikeRepository extends JpaRepository<CommentLikes, Long>{

    CommentLikes findByCommentId(long commentId);
}

评论回复仓库:

@Repository
public interface CommentReplyRepository extends JpaRepository<CommentReply, Long> {

    CommentReply findByReplyId(String replyId);

    @Transactional
    Long deleteByReplyId(String replyId);

}

评论仓库:

@Repository
public interface CommentRepository extends JpaRepository<CommentBean, Long>{
    List<CommentBean> findByTopicId(String topicId);
    CommentBean findByCommentId(long commentId);

    @Transactional
    Long deleteByCommentId(long deleteId);
}

主题存储库:

@Repository
public interface TopicRepository extends JpaRepository<TopicBean, Long> {
    TopicBean findByTopicId(String topicId);

    @Transactional
    Long deleteByTopicId(String topicId);

    List<TopicBean> findByUsername(String username);
}

用户信息存储库:

@Repository
public interface UserInfoRepository extends JpaRepository<UserInfo, Long>{

    UserInfo findByUsername(String username);

    UserInfo findRoleByUsername(String username);
}

最佳答案

因为您的标签包括 spring-boot 和 spring-jpa。
我假设你可以使用 spring 数据存储库

发布的实体不以任何方式关联。因此，必须关联实体才能检索一个存储库的所有数据 实体的修改版本如下所示:

评论表

@Entity
@Table(name = "comments")
public class CommentBean implements Serializable {

    @Id
    @Column(name = "id")
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @Column(name = "commentId")
    private long commentId;

    @ManyToOne
    @JoinColumn(name="topicId")
    private TopicBean topicBean;

    @OneToMany(mappedBy="commentBean")
    private List<CommentLikes> commentLikesList;
}

主题表

@Entity
@Table(name = "topics")
public class TopicBean implements Serializable {

    @Id
    @Column(name = "id")
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @Column(name = "topicId")
    private String topicId;
    @Column(name = "title")
    private String title;
    @Column(name = "details")
    private String details;
    @Column(name = "username")
    private String username;
    @Column(name = "userImage")
    private String userImage;
    @Column(name = "dayPosted")
    private String dayPosted;

    @OneToMany(mappedBy="topicBean")
    private List<CommentBean> commentBeans;
}

comment_likes 表

@Entity
@Table(name = "comment_likes")
public class CommentLikes implements Serializable {

    @Id
    @Column(name = "id")
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @Column(name = "commentLikes")
    private String commentLikes;

    @ManyToOne
    @JoinColumn(name="commentId")
    private CommentBean commentBean;
}

请注意，上述重写是基于我根据原始实体所能做出的最合理的猜测。

现在这三个实体已正确关联。 您可以只使用 TopicBean 存储库来检索所有 TopicBean，另外两个也将被检索。
topicBeanRepo.findAll()

关于java - spring jpa中根据实体从多个表中获取数据，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/42037275/

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