Question

I get this error only on certain situations. What I’m coding is a registration form, here is the basic code:

@Controller
@SessionAttributes("registrationForm")
@RequestMapping(value = "/registration")
public class RegistrationController
{
    @Autowired
    private RegistrationValidator registrationValidator;

    @RequestMapping(method = RequestMethod.GET)
    public String setupForm(Model model) throws Exception
    {
        return setupForm(model, new RegistrationForm());
    }

    @RequestMapping(method = RequestMethod.POST)
    public String submitForm(@ModelAttribute("registrationForm") RegistrationForm registrationForm,
                             Model model,
                             BindingResult result,
                             SessionStatus sessionStatus) throws Exception
    {
        registrationValidator.validate(registrationForm, result);

        if(result.hasErrors())
        {
            return setupForm(model, registrationForm);
        }
        else
        {
            // Do stuff

            sessionStatus.setComplete();

            return "redirect:success";
        }
    }

    private String setupForm(Model model, RegistrationForm registrationForm) throws Exception
    {
        model.addAttribute("currentYear", Calendar.getInstance().get(Calendar.YEAR));
        model.addAttribute("registrationForm", registrationForm);
        return "registration";
    }

The form:

<form:form method="POST" modelAttribute="registrationForm">
    ...
</form:form>

The very strange problem I have, is that if I clear the session data and I go straight to /registration, the whole registration process works perfectly. But when I call a page that is mapped in another controller first (i.e. home page), then I get the error specified in the title.

Can anyone help me?

Thank you.

Answer 1

Adding this solved the problem:

@ModelAttribute("registrationForm")
public RegistrationForm populateRegistrationForm()
{
    return new RegistrationForm();
}