Using @RequestParam for multiple POST-Parameters

Question

I have a very similiar problem solved in this thread: click

To make a long story short:

I'm generating form elements dynamically with jQuery and in the result it looks like this:

<div id="XYZ-1">
<input type="text" id="XYZ-1-position" name="XYZ-1-position" style="width: 20px;"/>
<input type="text" id="XYZ-1-input" name="XYZ-1-value" style="width: 400px;"/>
</div>

<div id="XYZ-2">
<input type="text" id="XYZ-2-position" name="XYZ-2-position" style="width: 20px;"/>
<input type="text" id="XYZ-2-input" name="XYZ-2-value" style="width: 400px;"/>
</div>

So for handling one form field, I'm using just this simple @ReqeustParam:

     @RequestMapping(value = "/data", method = RequestMethod.POST)
 public String myHandler(@RequestParam("XYZ-1-value")String content, Model model) {

    model.addAttribute("dataset", content); 
            return "data"

In the Thread of the beginning of my post it is solved like:

public String controllerMethod(@RequestParam(value="myParam[]") String[] myParams){
....
}

And this works for input types with the same name:

<input type="checkbox" name="myParam[]" value="myVal1" />
<input type="checkbox" name="myParam[]" value="myVal2" />

But the difference to my problem is, that my form elements do NOT have the same name - each has an individual Name.

So my question is how I can handle these individual post-parameters in a single handler in my controller.

Thanks in advance

CodeChimp · Accepted Answer · 2013-02-04T20:56:43.953

The pattern I like for this sort of thing is to have a form bean that contains a list (or map) of beans that wrap my individual values. So, I would have:

public class FormBean {
  private List<FormItem> items;
  //...getters/setters
}

and

public class FormItem {
  private String val1;
  private Integer val2;
  //...getters/setters
}

And controller method:

@RequestMapping()
public String default(@ModelAttribute("formBean") FormBean formBean) {
   // Blah blah blah
}

On the view-side, the mapping name would look like:

<input type="text" name="formBean.items[0].val1" />
<input type="text" name="formBean.items[0].val2" />

Or you could use the JSTL tags:

<form:form modelAttribute="formBean">
  <form:input path="items[0].val1" />
  <form:input path="items[0].val2" />
</form:form>

This way everything is nice and packaged up, and its really easy on the view-side to parse the name when adding new rows.

EDIT

Simple example on auto-placing models into session (I am typing this from memory...please validate on your own)

Controller:

@Controller
@RequestMapping("/form")
@SessionAttributes({"formBean"})
public class FormController {
    @RequestMapping()
    public String defaultView(@ModelAttribute("formBean") FormBean formBean, Model uiModel) {
        // Do something...add anything to the uiModel that you want to use in your form...you should not need to add formBean as it should auto-matically get put into session now with the @SessionAttributes annotation
        // Also to note, if you set the "formBean" attribute on the Model or ModelAndView, it will replace the one in Session.  Also, you can add the SessionStatus to one of your methods and use its .setComplete() method to indicate you are done with the session...you usually do this after you know the user is done with the application so the session can get cleaned up.
    }

    @RequestMapping("/someOtherPath")
    public String someOtherHandler(@ModelAttribute("formBean") FormBean formBean, Model uiModel) {
        // Do something...again, formBean should be either created or out of session
    }

    @ModelAttribute("formBean")
    private FormBean createFormBean() {
        // This method can be named anything, as long as it returns a FormBean, has the @ModelAttribute named on it, and has no arguments.  Use this method to populate your FormBean when its created (set defaults and such).
        return new FormBean();
    }
}

My result is alway null. I used formBean.getItems() to get the result but it's null. Could you give me an example? I used exactly the code you mentioned. thanks — fromspring2rails, Feb 03 '13 at 16:08
Which part is always null? The FormBean when you get into the Controller? — CodeChimp, Feb 04 '13 at 14:46
So I'm using the controller-method exactly like you said and in the view i have: ${formBean}. For ${formBean} in the view i get displayed com.project.org.FormBean@3dd261e0. It was empty when I used model.addAttribute("items", formBean.getItems()) and then tried to show it in the view with ${items}. But I guess there was no relation to the POST-data. Now, as I said, I'm getting the classname. Either there's missing an @Override-Method in the FormBean-class which calls the getItems()-Method automatically or ${formBean} in the view has to be iterated. What Do you think? — fromspring2rails, Feb 04 '13 at 20:39
Thanks for your huge effort by showing me how this works. I nearly got it now. Is it possible to have a short conversation with you via instant-messenger or IRC? This would help me a lot. — fromspring2rails, Feb 10 '13 at 18:28

score 0 · Answer 2 · answered Feb 01 '13 at 20:08

0

First, you don't need the [] - it will work without it. But if the name of each checkbox differs, then you need a separate @RequestParam for each checkbox.

answered Feb 01 '13 at 20:08

Bozho

588,226
146
1,060
1,140

Using @RequestParam for multiple POST-Parameters

2 Answers2

Linked