@Controller @RequestMapping("/user") public class UserController { @Autowired private UserService userService; @RequestMapping(value = "/{id}", method = RequestMethod.GET) public ResponseEntity<User> getUserById(@PathVariable("id") String id) { User user = userService.getUserById(id); if (user == null) { return new ResponseEntity<>(HttpStatus.NOT_FOUND); } return new ResponseEntity<>(user, HttpStatus.OK); } } <context:component-scan base-package="com.example.weibo.core" />