java - org.springframework.beans.factory.UnsatisfiedDependencyException ，没有类型 [edu.sample.service.ItemService] 的合格 bean

Question

这个问题已经有答案了:

What is a NoSuchBeanDefinitionException and how do I fix it? (1 个回答)

已关闭 6 年前。

这是 Spring Boot 应用程序。我遇到了异常。如何解决它请帮助我 我的 Controller 类是

import edu.sample.model.Item;
import edu.sample.service.ItemService;

@ComponentScan(basePackages = "edu.*")
@RestController
public class ItemController {

    @Autowired
    @Qualifier(value="itemService")
    private ItemService itemService;

    @RequestMapping(value = "/getAllItems", method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE)
    public ResponseEntity<List<Item>> getAllItems() {
        List<Item> items = itemService.getAllItems();
        return new ResponseEntity<List<Item>>(items, HttpStatus.OK);
    }
}

服务类别是

@Service
public class ItemServiceImpl implements ItemService {

    @Autowired
    ItemDAO itemDAO;

    @Override
    public String addItem(Item item) {
        return itemDAO.addItem(item);
    }

    @Override
    public String deleteItem(Integer id) {
        return itemDAO.deleteItem(id);
    } 

    @Override
    public void updateItem(Item item) {

    }

    @Override
    public List<Item> getAllItems() {
        return itemDAO.getAllItems();
    }

}

和 DAO 类

@Resource
public class ItemDAOImpl implements ItemDAO {

    @PersistenceContext
    EntityManager entityManager;

    @Override
    public String addItem(Item item) {
        entityManager.persist(item);
        return item.getName();
    }

    @Override
    public String deleteItem(Integer id) {
        String name=entityManager.find(Item.class, id).getName();
        entityManager.remove(id);
        return name;
    }

    @Override
    public void updateItem(Item item) {

    }

    @Override
    public List<Item> getAllItems() {
        return entityManager.createQuery("from Item").getResultList();
    }

}

我收到此异常消息:

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'itemController': Unsatisfied dependency expressed through field 'itemService': No qualifying bean of type [edu.sample.service.ItemService] found for dependency [edu.sample.service.ItemService]: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true), @org.springframework.beans.factory.annotation.Qualifier(value=itemService)}; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [edu.sample.service.ItemService] found for dependency [edu.sample.service.ItemService]: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true), @org.springframework.beans.factory.annotation.Qualifier(value=itemService)}

Answer 1

您必须使用限定符 "itemService" 来命名 ItemServiceImpl，如下所示:

@Service("itemService")
public class ItemServiceImpl implements ItemService {
    ...