Spring mvc from doesn't call controller

Question

I'm new using spring framework and I'm just creating my own project in order to catch the idea. The flow of this is loging -> customer list -> select one cusstomer -> Pet list. I have a button on first page with a form in order to add a customer and it is working properly. However, similar code to a second button in pet page to add a pet is not working. When I try to save the new pet, it is returning HTTP 400 – Bad Request and nothing in the console

pet-form.jsp:

 <form:form action="${pageContext.request.contextPath}/pet/savePet"
                modelAttribute="pet" method="POST">

                <!-- need to associate this data with customer id -->
                <form:hidden path="owner.id" />
    ......
    <td><input type="submit" value="Save" class="save" /></td>
                        </tr>

                    </tbody>
                </table>

PetController.java

@Controller
@RequestMapping("/pet")
public class PetController {
.....

    @PostMapping("/savePet")
    public String savePet(@ModelAttribute("pet") Pet thePet) {
        System.out.println("New Pet " + thePet.toString());

        thePet.setOwner(customerService.getCustomer(thePet.getOwner().getId()));

        System.out.println("Controller" + thePet);
        // save the customer using our service
        petService.savePet(thePet);

        return "redirect:/pet/showListPets";
    }

Any ideas what is happening?

Thanks in advance

Answer 1

I resolved my question, however I dont understand why, so, if someone is so kind to explain me.. better:) The problem was solved adding BindingResult paramenter to the controller method:

@PostMapping("/savePets")
    public String savePets(@ModelAttribute("pet") Pet thePet, BindingResult result) {

Thanks