@GetMapping(value = "/pets/new")
    public String initCreationForm(Owner owner, ModelMap model) {
        Pet pet = new Pet();
        owner.addPet(pet);
        model.put("pet", pet);
        return VIEWS_PETS_CREATE_OR_UPDATE_FORM;
    }
@author Juergen Hoeller
@author Ken Krebs
@author Arjen Poutsma
src/main/java/org/springframework/samples/petclinic/web/PetController.java