问如何从控制器调用服务

EN

@Service
class MyMailService {

    private final SendGrid sendGrid;

    @Inject
    public SendGridMailService(SendGrid sendGrid) {
        this.sendGrid = sendGrid;
    }

    void sendMail() {
        Request request = new Request();
        Response response = this.sendGrid.api(request);                
    }
}

# controller
public String index(Model model) {
    MyMailService.sendMail() // how to do this properly?
    return "register";
}