CODEWITHSUNDEEP
javaspringjspspring-mvcspring-annotations
Human Being
Human Being

Reputation: 8387

Spring MVC form - No items in dropdown list?

My form has one text field and one dropdown list.When my form loads first time there is a list of values in the dropdown list.

If I am submitting the form , and my form has any errors , I am trying to return the same form to show the errors and to resubmit the missed data.

But if my form reloads through the POST method of controller , there is no values in the dropdown list.

My spring controller ,

@Controller
public class FormController {

    private ListStore getList;

    @RequestMapping(value="/ApplicationForm.html",method=RequestMethod.GET)
    public String displayForm(@ModelAttribute UserData userData,ModelMap map){

        map.addAttribute("age",(ArrayList<String>)getList.ageList());
        return "ApplicationForm";
    }

    @RequestMapping(value="/ApplicaitonForm.html",method=RequestMethod.POST)
    public String displayFormDetails(@Valid UserData data,BindingResult result,ModelMap map,@RequestParam(value="name",required=true) String name,@RequestParam("age") String age){

        if(result.hasErrors()){
            System.out.println("It has some errors !!!!!!!!");
            return "ApplicationForm";
        }
        map.addAttribute("name", name);
        map.addAttribute("age", age);

        return "DisplayFormDetails";
    }
}

My ListStore class will be,

public class ListStore {

    public List<String> ageList(){
        LinkedList<String> list = new LinkedList<String>();
        list.add("20 to 25 years");
        list.add("25 to 35 years");
        list.add("above 35 years");
        return list;
    }
 }

How to restore the values in the dropdown list , when my form reloads through the POST method of the controller ?

But I solved this issue by adding map.addAttribute("age",(ArrayList<String>)getList.ageList()); as in my code as,

    if(result.hasErrors()){
        System.out.println("Form has some errors !!!!!!!!");
        map.addAttribute("age",(ArrayList<String>)getList.ageList());
        return "ApplicationForm";
    }

But is there any other way to do this easily ?

Hope our stack members will help me.

Upvotes: 2

Views: 1643

Answers (4)

michal.kreuzman
michal.kreuzman

Reputation: 12390

I'm usually calling display method from action (POST) method to avoid code duplication. See your slightly modified code below. I've also made small change in your code to follow Post/Redirect/Get pattern.

@Controller
public class FormController {

    private ListStore getList;

    @RequestMapping(value="/ApplicationForm.html", method=RequestMethod.GET)
    public String displayForm(@ModelAttribute UserData userData, Model model){

        model.addAttribute("age", getList.ageList());
        return "ApplicationForm";
    }

    @RequestMapping(value="/ApplicaitonForm.html", method=RequestMethod.POST)
    public String processForm(@Valid UserData data, 
                              BindingResult result, 
                              Model model, 
                              @RequestParam(value="name", required=true) String name, 
                              @RequestParam("age") String age, 
                              RedirectAttributes redirectAttributes) {

        if(result.hasErrors()){
            System.out.println("It has some errors !!!!!!!!");
            return displayForm(data, model); /* THIS IS THE TRICK :) */
        }

        redirectAttributes.addFlashAttribute("name", name);
        redirectAttributes.addFlashAttribute("age", age);

        return "redirect:/DisplayFormDetails.html"; // Redirect here to follow Post/Redirect/Get pattern
    }

    @RequestMapping(value="/DisplayFormDetails.html", method=RequestMethod.GET)
    public String displayFormDetails(Model model){
        // name and age are already in model due to use of RedirectAttributes
        return "DisplayFormDetails";
    }
}

Upvotes: 1

Muhammad Imran Tariq
Muhammad Imran Tariq

Reputation: 23352

@ModelAttribute will help you.

@ModelAttribute
    public ModelMap setupForm(ModelMap modelMap) {

        modelMap.put("age",(ArrayList<String>)getList.ageList());
        return modelMap;
    }

This is a nice article for understanding about handling Spring forms.

Upvotes: 0

user980089
user980089

Reputation: 374

Add @Autowired annotation on getList property.

@Controller
public class FormController {

    @Autowired //annotation added
    private ListStore getList;
    -----

Upvotes: 0

Jayesh
Jayesh

Reputation: 6111

I can see from your code that ,

if your form has error then it is simply returning "ApplicationForm" view Name with no Model data exposed to view which view will display 

  if(result.hasErrors()){
            System.out.println("It has some errors !!!!!!!!");
            return "ApplicationForm";
   }

Upvotes: 0

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