@Autowired private UserService userService;
时间: 2024-05-25 20:17:32 浏览: 10
This code is using the Spring Framework's dependency injection feature to inject an instance of the UserService class into the current class.
The @Autowired annotation is used to mark the userService variable as a dependency to be injected, and Spring will automatically create and inject an instance of the UserService class into the variable when the current class is instantiated.
This reduces the need for manual instantiation of dependencies and makes the code more modular and easier to maintain.
相关问题
@Autowired private IUserService userService;
这是一个Java代码片段,使用了Spring框架的自动注入功能,将一个名为userService的bean注入到当前类中。通常情况下,会在ApplicationContext容器中定义一个名为userService的bean,并且该bean的类型是IUserService。这样,在运行时,Spring框架会自动将该bean注入到当前类中,使得我们可以在当前类中使用userService的相关方法和属性。
帮我改写以下代码,不要用servlet.代码为:@Controller public class CartController { @Autowired private UserService userService; @Autowired private CommodityService commodityService; @Autowired private CartService cartService; @GetMapping("/cart") public String cart(Model model, HttpServletRequest request) { HttpSession session = request.getSession(); User user = (User)session.getAttribute("user"); if (user == null) { return "redirect:/login"; } List<Cart> cartList = cartService.findByUid(user.getUid()); model.addAttribute("cartList", cartList); return "cart"; } @PostMapping("/cart/add") public String addCart(Integer cid, Integer cnum, HttpServletRequest request) { HttpSession session = request.getSession(); User user = (User)session.getAttribute("user"); if (user == null) { return "redirect:/login"; } Commodity commodity = commodityService.findById(cid); if (commodity == null) { return "redirect:/commodity"; } Cart cart = new Cart(); cart.setUid(user.getUid()); cart.setCid(cid); cart.setCnum(cnum); cartService.save(cart); return "redirect:/cart"; } @PostMapping("/cart/delete") public String deleteCart(Integer cartid) { cartService.deleteById(cartid); return "redirect:/cart"; }
以下是改写后的代码,使用了Spring Boot的@RestController注解和@ResponseBody注解来实现API风格的接口:
@RestController
public class CartController {
@Autowired
private UserService userService;
@Autowired
private CommodityService commodityService;
@Autowired
private CartService cartService;
@GetMapping("/cart")
public List<Cart> getCart(HttpServletRequest request) {
HttpSession session = request.getSession();
User user = (User)session.getAttribute("user");
if (user == null) {
return null;
}
List<Cart> cartList = cartService.findByUid(user.getUid());
return cartList;
}
@PostMapping("/cart/add")
public String addCart(Integer cid, Integer cnum, HttpServletRequest request) {
HttpSession session = request.getSession();
User user = (User)session.getAttribute("user");
if (user == null) {
return "redirect:/login";
}
Commodity commodity = commodityService.findById(cid);
if (commodity == null) {
return "redirect:/commodity";
}
Cart cart = new Cart();
cart.setUid(user.getUid());
cart.setCid(cid);
cart.setCnum(cnum);
cartService.save(cart);
return "success";
}
@PostMapping("/cart/delete")
public String deleteCart(Integer cartid) {
cartService.deleteById(cartid);
return "success";
}
}
这里将原来的@Controller注解改为@RestController注解,表示这是一个API控制器,不需要返回视图,而是直接返回数据。同时,将原来的Model和视图名称改为了List<Cart>,表示返回一个购物车列表。为了让返回的数据能够被前端页面接收到,我们使用@ResponseBody注解将返回值转为JSON格式。最后,将原来的重定向操作改为返回字符串"success",表示操作成功。
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