这是第5页上的示例中的动态

OrderController.java

@Controller
@RequestMapping("/orders")
@SessionAttributes("order")
public class OrderController {

    private OrderRepository orderRepo;

    public OrderController(OrderRepository orderRepo) {
        this.orderRepo = orderRepo;
    }

    @GetMapping("/current")
    public String orderForm() {
        return "orderForm";
    }

    @PostMapping
    public String processOrder(@Valid Order order,Errors errors,SessionStatus sessionStatus) {
        if (errors.hasErrors()) {
            return "orderForm";
        }

        orderRepo.save(order);
        sessionStatus.setComplete();

        return "redirect:/";
    }

}

OrderRepository.java

public interface OrderRepository {

  Order save(Order order);

}

为什么我可以使用此代码而不添加@Autowired 感谢您的帮助。

public OrderController(OrderRepository orderRepo) {
        this.orderRepo = orderRepo;
    }