public class UserController {

    @PostMapping("/login")
    public ResponseEntity<String> login(@RequestBody LoginRequest request) {
        // Authenticate the user using Spring Security
        UsernamePasswordAuthenticationToken token = new UsernamePasswordAuthenticationToken(
            request.getUsername(),
            request.getPassword()
        );
        Authentication authentication = authenticationManager.authenticate(token);
        SecurityContextHolder.getContext().setAuthentication(authentication);

        // Generate JWT token
        String tokenValue = jwtUtil.generateToken(authentication);

        return ResponseEntity.ok().body(tokenValue);
    }
}

public class LoginPage extends WebPage {

    public LoginPage() {
        Form loginForm = new Form("loginForm");
        loginForm.add(new TextField("username"));
        loginForm.add(new PasswordTextField("password"));
        loginForm.add(new SubmitLink("submit"));

        // Authenticate the user using Shiro
        loginForm.onSubmit(event -> {
            Subject subject = ShiroSubject.getSubject();
            UsernamePasswordToken token = 
            new UsernamePasswordToken(
                getForm().get("username").getValue(),
                getForm().get("password").getValue()
            );
            subject.login(token);
        });
    }
}

public class MainView extends VerticalLayout {

    public MainView() {
        // Authenticate the user using Vaadin
        VaadinSession.getCurrent().setAttribute(AccessControlFactory.USER_ID_ATTRIBUTE, "user@example.com");

        // Check if the user is authorized to <a style='color:#f60; text-decoration:underline;' href="https://www.php.cn/zt/16380.html" target="_blank">access</a> this view
        if (!AccessControlFactory.checkUserRole("admin")) {
            Label unauthorizedLabel = new Label("Unauthorized");
            addComponent(unauthorizedLabel);
        } else {
            // Add authorized content
            Button button = new Button("Authorized button");
            addComponent(button);
        }
    }
}