spring boot不能注入JpaRepository接口，提示找不到bean，解决方案

控制台报错信息：

Description:

Field userRepository in com.example.demo.controller.UserController required a bean of type 'com.example.demo.repository.UserRepository' that could not be found.

Action:

Consider defining a bean of type 'com.example.demo.repository.UserRepository' in your configuration.

UserRepository:

@Repository
public interface UserRepository extends JpaRepository<User, Long> {
 
}

UserController:

@RestController
public class UserController {
     @Autowired
     private UserRepository userRepository;
     @GetMapping("/simple/{id}")
     public User findById(@PathVariable Long id) {
         return this.userRepository.findOne(id);
     }
}

使spring 扫描到文件
解决方法：启动类进行扫描

@SpringBootApplication
@ComponentScan（"com"）//扫描com下所有文件
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class,args);
    }
}

翻译自https://stackoverflow.com/questions/40384056/consider-defining-a-bean-of-type-package-in-your-configuration-spring-boot