Spring mvc how to add a variable in controller and use it as a condition in jsp

Question

Hi i have the following code that is executed when i submit form:

@ActionMapping(params = "ConController=showPayment")
public void showPayment(ActionResponse response, @ModelAttribute("conPayForm") ConsiPayForm consiForm, Model model) {
        PaymentDetailsResponse paymentDetailsResponse = stand.getDet();

           ViewDet view = stand.getView();
            ...
            PaymentDetails paymentDetails = paymentDetailsResponse.getPayDetails();
            ....        
            model.addAttribute("paymentDetails", paymentDetails);
        }
    }

The bean is:

ViewDet.class

    List <String> colours;
    List <String> design;
    ...

Once showPayment method is completed view.jsp is displayed and i am using jstl in the jsp. I have a view button in the jsp, and basically I want to add a check in the view.jsp that if colours and design are empty then hide the view button. Any idea how to do it from the controller please?

Answer 1

You need to add values in modelAndView object which is equivalent to adding in request and you need to return modelAndView from controller method.

     @ActionMapping(params = "ConController=showPayment")
        public ModelAndView showPayment(ActionResponse response, @ModelAttribute("conPayForm") ConsiPayForm consiForm, Model model) {
                PaymentDetailsResponse paymentDetailsResponse = stand.getDet();

                   ViewDet view = stand.getView();
                    ...
                    PaymentDetails paymentDetails = paymentDetailsResponse.getPayDetails();
                    ....        
                    model.addAttribute("paymentDetails", paymentDetails);
                    ModelAndView modelAndView = new ModelAndView("view"); //as per view resolver
                    modelAndView.addObject("",colorsList);
                    modelAndView.addObject("design",designList);
                    return modelAndView;
                }
            }

In jsp you can check these attributes using jstl

<c:if test="${not empty colorsList}">
... display button
</c:if>

Here is some simple example.

Answer 2

use c:if tag

test your variable in the c:if condition pass  your variables from controller and check

    <c:if test="${colors}==null&&${design}==null">
// if condition is true then it will display the button otherwise not
    <input type=button value="view"/>

    </c:if>