@InitBinder
    public void setAllowedFields(WebDataBinder dataBinder) {
        dataBinder.setDisallowedFields("id");
    }
@author Juergen Hoeller
@author Ken Krebs
@author Arjen Poutsma
@author Michael Isvy
src/main/java/org/springframework/samples/petclinic/web/VisitController.java