java - 在springboot中获取存储库对象null

Question

我有以下项目结构

我的代码文件如下

DemoApplication.java

@SpringBootApplication
public class DemoApplication implements CommandLineRunner {

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

    @Override
    public void run(String... args) throws Exception {
        CarListGrabber grabber = new CarListGrabber();
        grabber.grabCarsWithName("Test");
    }

}

NewCarRepository.java

@Repository
public interface NewCarRepository extends CrudRepository<NewCar, Long> {

}

新汽车.java

@Entity
@Table(name = "new_car_details")
public class NewCar {
    // member variables with default constructor
}

CarListGrabber.java

@Service
public class CarListGrabber {

    @Autowired
    private NewCarRepository newCarRepository;

    // someOtherStuff
}

即使我使用了注释@Repository，@Service 我在服务中得到空存储库对象。

标签： javaspring-bootdependency-injection

Answer 1

您正在实例化一个新CarListGrabber的：

CarListGrabber grabber = new CarListGrabber();

它不会进行您需要注入的注射grabber，例如：

@Autowired
CarListGrabber grabber;