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

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.