提交表单而不刷新Spring MVC中的页面

Question

I have a listbox2 that's filled according to what has been selected in the listbox1. So when i submit the form, i lose the data of listbox2 and i have to reselect in the listbox1 again. How can i keep data in listbox2 after submitting ?

<form:form action="choseElement" method="post"> 
<select name="listbox1">
 <j:forEach items="${elementList}" var="elem">
   <option>${elem.name}</option>
 </j:forEach>
</select>
</form:form>
<form:form action="addProduct" method="post"> 
 <input type="text" name="nameProd">
 <select name="listbox2">
 <j:forEach items="${LPbyElement}" var="lp">
   <option>${lp.name}</option>
 </j:forEach>
 </select>
</form:form>

Answer 1

You should use Ajax to achieve this

    function getSubList(val){
           $.ajax({
                url: 'your-url',
                type: 'post',
                data: {param:val},
                success: function (msg) {
                    $('#id-of-sublist').html(msg);
                },

            });
    }

Now in your first list you can call onChange(this.value)

Note : Your server should return values in the below format

<option>value1</option>
<option>value2</option>

Answer 2

when i submit the form, i lose the data of listbox2 and i have to reselect in the listbox1 again.

you have not mentioned about how you binding your form data and passes to controller from jsp, am considering you have model bean like below:

ProductBean class to hold form data:

public class ProductBean {

private String listbox1Selected;
private String listbox2Selected;

  //no-arg constructor, getters and setters
}

Option class to load options in listbox or selectbox:

public class Option {    
    private String name;

    public Option(){}

    public Option(String name) {
        super();
        this.name = name;
    }
}

and in jsp use like below to get selected option after form submit:

<form:form method="post" modelAttribute="productBean">
    <label  for="listbox1">listbox1:</label>
    <form:select path="listbox1Selected">
        <option value="NONE">--listbox1--</option>
        <form:options items="${listbox1Options}" itemValue="name" itemLabel="name"/>
    </form:select>

    <label  for="listbox2">listbox2:</label>            
    <form:select path="listbox2Selected">
        <option value="NONE">--listbox2--</option>
        <form:options items="${listbox2Options}" itemValue="name" itemLabel="name"/>
    </form:select>

    <input type="submit" />
</form:form>

and in controller return the product model bean what spring passed to POST parameter.

@Controller
@RequestMapping("/selectBox")
public class SelectBoxController {

    @RequestMapping(method=RequestMethod.GET)
    public String showSelectBox(Model model){

        model.addAttribute("productBean", new ProductBean());
        return "selectBox";
    }

    @RequestMapping(method=RequestMethod.POST)
    public String showSelectBox(@ModelAttribute("productBean")ProductBean productBean, BindingResult result, ModelMap model){
        System.out.println(productBean);
        model.addAttribute("productBean", productBean);
        return "selectBox";
    }

    @ModelAttribute("listbox1Options")
    public List<Option> populateOpt(){
        List<Option> lst = new ArrayList<Option>();
        lst.add(new Option("Op1"));
        lst.add(new Option("Op2"));
        lst.add(new Option("Op3"));
        return lst;
    }

    @ModelAttribute("listbox2Options")
    public List<Option> populateOpt2(){
        List<Option> lst = new ArrayList<Option>();
        lst.add(new Option("Op4"));
        lst.add(new Option("Op5"));
        lst.add(new Option("Op6"));
        return lst;
    }
}