我的Web應用程序存在一個小問題：一個與spring boot API連接的angular2應用程序。我無法從angular2應用訪問我的請求。我收到此錯誤：Failed to load http://localhost:8080/deliveryMan/: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:4200' is therefore not allowed access.Java代碼：@RestController@RequestMapping(value = "/deliveryMan")@CrossOriginpublic class DeliveryManController {    @Autowired    DeliveryManService deliveryManService;    @RequestMapping(value = "/getAllDeliveryMan", method = RequestMethod.GET)    public Iterable<DeliveryMan> getAllDeliveryMan(){        return deliveryManService.findAll();    }    @RequestMapping(method = RequestMethod.PUT, consumes = "application/json")    public DeliveryMan addDeliveryMan(@RequestBody DeliveryMan deliveryMan) throws InvalidObjectException {        deliveryManService.save(deliveryMan);        return deliveryMan;    }@SpringBootApplication@EnableAutoConfiguration@ComponentScanpublic class MyApp{    public static void main(String[] args) {        SpringApplication.run(MyApp.class, args);    }}angular2代碼：private apiUrl = 'http://localhost:8080/deliveryMan/';getAll(): Promise<DeliveryMan[]> {  const url = this.apiUrl + 'getAllDeliveryMan';  return this.http.get(url)    .toPromise()    .then(response => response.json().data as DeliveryMan[])    .catch(this.handleError);}saveDeliveryMan(deliveryMan: DeliveryMan): Promise<DeliveryMan> {  const url = this.apiUrl;  return this.http.put(url, JSON.stringify(deliveryMan), this.headers)    .toPromise()    .then(() => deliveryMan)    .catch(this.handleError);}為了解決該問題，我在控制器類中添加了@CrossOrigin。它解決了getAll方法的問題，但沒有解決其他方法的問題。如何解決它，以便我可以使用PUT方法而不會出現此錯誤？