Question

我是Spring框架的初学者，

我在存储库和SQL连接部分遇到了一些问题。我想使用连接查询从两个表中获取详细信息。

请在错误下方查找

org.springframework.beans.factory.UnsatisfiedDependencyException：创建名称为'commentController'的bean时出错：不满意通过字段“ joinRepository”表示的依赖关系；嵌套异常是org.springframework.beans.factory.BeanCreationException：错误创建名称为“ joinRepository”的bean：初始化方法的调用失败嵌套异常是java.lang.IllegalArgumentException：不是托管类型：com.example.jpa.model.JoinQuery类，位于 org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor $ AutowiredFieldElement.inject（AutowiredAnnotationBeanPostProcessor.java:643）〜[spring-beans-5.2.6.RELEASE.jar：5.2.6.RELEASE]在 org.springframework.beans.factory.annotation.InjectionMetadata.inject（InjectionMetadata.java:130）〜[spring-beans-5.2.6.RELEASE.jar：5.2.6.RELEASE]在 org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties（AutowiredAnnotationBeanPostProcessor.java:399）〜[spring-beans-5.2.6.RELEASE.jar：5.2.6.RELEASE]在 org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean（AbstractAutowireCapableBeanFactory.java:1422）〜[spring-beans-5.2.6.RELEASE.jar：5.2.6.RELEASE]在 org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean（AbstractAutowireCapableBeanFactory.java:594）〜[spring-beans-5.2.6.RELEASE.jar：5.2.6.RELEASE]在 org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean（AbstractAutowireCapableBeanFactory.java:517）〜[spring-beans-5.2.6.RELEASE.jar：5.2.6.RELEASE]在 org.springframework.beans.factory.support.AbstractBeanFactory.lambda $ doGetBean $ 0（AbstractBeanFactory.java:323）〜[spring-beans-5.2.6.RELEASE.jar：5.2.6.RELEASE]在 org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton（DefaultSingletonBeanRegistry.java:226）〜[spring-beans-5.2.6.RELEASE.jar：5.2.6.RELEASE]在 org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean（AbstractBeanFactory.java:321）〜[spring-beans-5.2.6.RELEASE.jar：5.2.6.RELEASE]在 org.springframework.beans.factory.support.AbstractBeanFactory.getBean（AbstractBeanFactory.java:202）〜[spring-beans-5.2.6.RELEASE.jar：5.2.6.RELEASE]在 org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons（DefaultListableBeanFactory.java:895）〜[spring-beans-5.2.6.RELEASE.jar：5.2.6.RELEASE]在 org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization（AbstractApplicationContext.java:878）〜[spring-context-5.2.6.RELEASE.jar：5.2.6.RELEASE]在 org.springframework.context.support.AbstractApplicationContext.refresh（AbstractApplicationContext.java:550）〜[spring-context-5.2.6.RELEASE.jar：5.2.6.RELEASE]在 org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh（ServletWebServerApplicationContext.java:141）〜[spring-boot-2.2.7.RELEASE.jar：2.2.7.RELEASE]在 org.springframework.boot.SpringApplication.refresh（SpringApplication.java:747） [spring-boot-2.2.7.RELEASE.jar：2.2.7.RELEASE]位于 org.springframework.boot.SpringApplication.refreshContext（SpringApplication.java:397） [spring-boot-2.2.7.RELEASE.jar：2.2.7.RELEASE]位于 org.springframework.boot.SpringApplication.run（SpringApplication.java:315） [spring-boot-2.2.7.RELEASE.jar：2.2.7.RELEASE]位于 org.springframework.boot.SpringApplication.run（SpringApplication.java:1226） [spring-boot-2.2.7.RELEASE.jar：2.2.7.RELEASE]位于 org.springframework.boot.SpringApplication.run（SpringApplication.java:1215） [spring-boot-2.2.7.RELEASE.jar：2.2.7.RELEASE]位于 com.example.jpa.JpaOneToManyDemoApplication.main（JpaOneToManyDemoApplication.java:14） [classes /：na]

select c.created_at , c.updated_at , p.content,c.text , p.id , c.posting_dummy 
from     post p join  comment c 
on  p.id = c.posting_dummy;

存储库：

@Repository
public interface JoinRepository  extends JpaRepository<JoinQuery, Long>
{
@Query(value = " select  c.created_at , c.updated_at , p.content,c.text , p.id , c.posting_dummy "
            + "  from   post p join  comment c   on  p.id = :id ", nativeQuery = true)
public  List<JoinQuery> queryBy(Long id);
}

POJO：

public class JoinQuery 
{
private Long id;
private Date createdAt;
private Date updatedAt;
private String content;
private String text;
private  Post posting_dummy;

// Getter and Setter for fields       
}

控制器：

@RestController
public class CommentController {

@Autowired
private CommentRepository commentRepository;

@Autowired
private PostRepository postRepository;

@Autowired
private JoinRepository joinRepository;

@GetMapping("/posts/{postId}/comments")
public List<JoinQuery>  getAllCommentsByPostId(@PathVariable (value = "postId") Long postId
                                                    ) 
{
System.out.println("hi am here ");
return joinRepository.queryBy(postId);
}

}

Answer 1

public class JoinQuery需要@Entity注释。

@Entity
public class JoinQuery 
{
private Long id;
private Date createdAt;
private Date updatedAt;
private String content;
private String text;
private  Post posting_dummy;

// Getter and Setter for fields       
}

该查询也不应该是本机查询使用：

@Query(value = " select  new <package of jpaquery>.JoinQuery(c.created_at , c.updated_at , p.content,c.text , p.id , c.posting_dummy) "
            + "  from   post p.c")

BTW：请勿将Entity用作控件的返回值。了解3tier架构

春季JPA加入

1 个答案: