SpringMVC controller: how to stay on page if form validation error occurs

Question

I have next working code in my SpringMVC controller:

@RequestMapping(value = \"/register\", method = RequestMethod.GET)
public void registerForm(Mod         


        

Answer 1

*I'm using Hibernate Validator APIs to validate my beans. To preserve form data along with displaying error messages, you need to do these 3 things:

1. Annotate your bean (eg. @NotEmpty, @Pattern, @Length, @Email etc.)

2. Inside controller:

   @Controller public class RegistrationController {

   @Autowired
   private RegistrationService registrationService;
   
   @RequestMapping(value="register.htm", method=RequestMethod.GET, params="new")
   public String showRegistrationForm(Model model) {
       if (!model.containsAttribute("employee")) {
           model.addAttribute("employee", new Employee());
       }
       return "form/registration";
   }
   
   @RequestMapping(value="register.htm", method=RequestMethod.POST)
   public String register(@Valid @ModelAttribute("employee") Employee employee, BindingResult bindingResult, RedirectAttributes redirectAttributes) {
       if (bindingResult.hasErrors()) {
           redirectAttributes.addFlashAttribute("org.springframework.validation.BindingResult.employee", bindingResult);
           redirectAttributes.addFlashAttribute("employee", employee);
           return "redirect:register.htm?new";
       }
       registrationService.save(employee);
       return "workspace";
   }
   // ....
   

   }

3. Update your view/jsp to hold error messages:

This article can surely be helpful.

Answer 2

You can change your POST implementation to this:

@RequestMapping(value = "/buy/{buyId}", method = RequestMethod.POST)
public String buyPost(@PathVariable long buyId,
                          @Valid @ModelAttribute("buyForm") BuyForm buyForm,
                          BindingResult result) {

    buyForm.setId(buyId); // important to do this also in the error case, otherwise, 
                          // if the validation fails multiple times it will not work.

    if (result.hasErrors()) {
        byForm.setId(buyId);
        return "/buy/{buyId}";
    }

    buyService.buy(buyForm);
    return "redirect:/show/{buyId}";
}

Optionally, you can also annotate the method with @PostMapping("/buy/{buyId}") if you use Spring 4.3 or higher.

Answer 3

I tried the solution metioned in this post at this weekend, but it doesn't work for BindingResult.

The code below works but not perfect.

@ModelAttribute("command")
public PlaceOrderCommand command() {
    return new PlaceOrderCommand();
}

@RequestMapping(value = "/placeOrder", method = RequestMethod.GET)
public String placeOrder(
        @ModelAttribute("command") PlaceOrderCommand command,
        ModelMap modelMap) {
    modelMap.put(BindingResult.MODEL_KEY_PREFIX + "command",
            modelMap.get("errors"));
    return "placeOrder";
}

@RequestMapping(value = "/placeOrder", method = RequestMethod.POST)
public String placeOrder(
        @Valid @ModelAttribute("command") PlaceOrderCommand command,
        final BindingResult bindingResult, Model model,
        final RedirectAttributes redirectAttributes) {
    if (bindingResult.hasErrors()) {
        redirectAttributes.addFlashAttribute("errors", bindingResult);

        //it doesn't work when passing this          
        //redirectAttributes.addFlashAttribute(BindingResult.MODEL_KEY_PREFIX + "command", bindingResult);

        redirectAttributes.addFlashAttribute("command", command);
        return "redirect:/booking/placeOrder";
    }
    ......
}