如何为Springboot JPA建立通用的通用存储库

如何解决如何为Springboot JPA建立通用的通用存储库

这是我的模特：-

    @MappedSuperclass
public class IdCommon {

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

    @Version
    private Long version;

    @CreatedBy
    @Column(name = "created_by")
    private String createdBy;

    @CreatedDate
    private Instant created;

    @LastModifiedBy
    @Column(name = "updated_by")
    private String updatedBy;

    @LastModifiedDate
    private Instant updated;

}



    @Entity
@Table(name="TBL_EMPLOYEES")
public class EmployeeEntity extends IdCommon {
    
    @Column(name="first_name")
    private String firstName;
    
    @Column(name="last_name")
    private String lastName;
    
    @Column(name="email",nullable=false,length=200)
    private String email;
    
    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    @Override
    public String toString() {
        return "EmployeeEntity [id=" + 0 + ",firstName=" + firstName +
                ",lastName=" + lastName + ",email=" + email   + "]";
    }
}

我的存储库和服务：-

@Repository
public interface CommonRepository<E extends IdCommon> extends JpaRepository<E,Long>,JpaSpecificationExecutor<E> {

  }

 @Service
 public class EmployeeService {

//@Autowired
EmployeeRepository repository;

//@Autowired
CommonRepository<EmployeeEntity> commonRepository;

@Autowired
public EmployeeService(EmployeeRepository repository,CommonRepository<EmployeeEntity> commonRepository) {
    this.repository = repository;
    this.commonRepository = commonRepository;
}

public Page<EmployeeEntity> getAll(Pageable pageable){
    Specification<EmployeeEntity> specification = (Specification<EmployeeEntity>) (root,query,builder) -> null;
    return commonRepository.findAll(specification,pageable);
}
}

控制器：-

    @RestController
@RequestMapping(path = "/employee")
public class EmployeeController2 {

    @Autowired
    private EmployeeService employeeService;

    @GetMapping(path = "/all")

    @ApiImplicitParams({
            @ApiImplicitParam(name = "page",dataType = "integer",paramType = "query",value = "page number"),@ApiImplicitParam(name = "size",value = "Number of records per page."),})
    public Page<EmployeeEntity> getAll(@RequestParam(value = "sortBy",required = false,defaultValue = "created") String sortBy,@ApiIgnore Pageable pageable,@ApiParam(value = "sortDirection (desc/asc)")
                                       @RequestParam(value = "sortDirection",defaultValue = "asc") String sortDirection){
        if (sortDirection.equals("desc")) {
            pageable = PageRequest.of(pageable.getPageNumber(),pageable.getPageSize(),Sort.by(sortBy).descending());
        } else {
            pageable = PageRequest.of(pageable.getPageNumber(),Sort.by(sortBy).ascending());
        }
        return employeeService.getAll(pageable);
    }
}

我收到此错误：-

：Servlet [dispatcherServlet]中的Servlet.service（）路径[]引发异常[请求处理失败；嵌套异常是org.springframework.dao.InvalidDataAccessApiUsageException：不是实体：com.howtodoinjava.demo.model.IdCommon类；嵌套异常是java.lang.IllegalArgumentException：不是实体：类 com.howtodoinjava.demo.model.IdCommon]的根本原因

java.lang.IllegalArgumentException：不是实体：类 com.howtodoinjava.demo.model.IdCommon

如上述错误所述，它不是实体。因此，我在@IdCommon中添加了@Entity批注。然后我得到了新的错误：-

org.springframework.beans.factory.BeanCreationException：错误在类路径中创建名称为“ entityManagerFactory”的bean 资源 [org / springframework / boot / autoconfigure / orm / jpa / HibernateJpaConfiguration.class]：调用init方法失败；嵌套异常为 org.hibernate.AnnotationException：无法使用注释实体 @Entity和@MappedSuperclass： com.howtodoinjava.demo.model.IdCommon

我该如何实现？我的要求是具有通用存储库类型。我将有许多类似的实体。为了避免很多代码，我应该使用泛型。

解决方法

已经有一段时间了，希望您已经有了解决方案。但是，对于其他面临相同问题的人，我将尝试找出您的解决方案无法正常工作的原因。

第一件事是，您的存储库必须使用@NoRepositoryBean进行注释，如下所示：

@NoRepositoryBean
public interface CommonRepository<E extends IdCommon> extends JpaRepository<E,Long>,JpaSpecificationExecutor<E> {}

并将在EmployeeRepository中消失：

public interface EmployeeRepository extends CommonRepository<EmployeeEntity> {
    //you can override some or all of the methods if necessary
}

服务类别大致相同：

@Service
public class EmployeeService {

    private EmployeeRepository empRepository;

    public EmployeeService(EmployeeRepository repository) {
        this.empRepository = repository;
    }

    public void saveEmployee(EmployeeEntity entity) {//I added this for a test
        empRepository.save(entity);
    }
    
    public Page<EmployeeEntity> getAll(Pageable pageable) {
        Specification<EmployeeEntity> specification = (Specification<EmployeeEntity>) (root,query,builder) -> null;
        return empRepository.findAll(specification,pageable);
    }
}

并使用CommandLineRunner运行它（懒惰地添加控制器）

@SpringBootApplication
public class DemoApplication implements CommandLineRunner {

    @Autowired
    private EmployeeService service;

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class,args);
    }

    @Override
    public void run(String... args) throws Exception {
        EmployeeEntity entity = new EmployeeEntity();
        entity.setEmail("aa@so.com");
        entity.setFirstName("First name");
        entity.setLastName("Last name");
        
        service.saveEmployee(entity);
        
        Page<EmployeeEntity> page = service.getAll(PageRequest.of(0,1));
        page.getContent().stream().forEach(System.out::println); //output: EmployeeEntity [id=0,firstName=First name,lastName=Last name,email=aa@so.com]
    }

}