I cant pass an array from JSP to Servlet

Question

I have a JSP which creates a table when it is loaded doing a query on a database and showing the content of the result set.
The data showed are some items' names and at the end of each row there is a text field where the user can write the quantity of each item to buy.
I need to send to a servlet the name and the quantity of each item with a quantity value > 0.
This is what I think to do:
in the text field I've put an onChange event which calls a javascript function, the function inserts the item and the quantity inside an array if the quantity is > 0, removes the item if the quantity is <= 0.
The submit button calls another function which put the array in the session
session.setAttibute("daAcquistare",daAcquistare);
daAcquistare is my array created in the JSP
var daAcquistare = new Array();
Inside the servlet I don't know how to take that array since if I do like this
String[] ingrediente = new String[i*2];
HttpSession session = request.getSession();
ingrediente = session.getAttribute("daAcquistare");
I obtain "Cannot convert from Object to String[]"
How can I do to have that array inside the servlet?

Answer 1

Thankyou for your reply.
This is my form:
<form name="rimanenze" action="VerificaRimanenze" method="post">
<table width="650" border="0" cellpadding="6">
     <tr>
          <td width="25%"><b>Ingrediente</b></td>
          <td width="25%"><p align="center"><strong>Unit� di misura</strong></p></td>
          <td width="20%"><p align="center"><strong>Disponibilit�</strong></p></td>
          <td width="20%"><p align="center"><strong>Soglia</strong></p></td>
          <td width="10%"><p align="center"><strong>Acquista</strong></p></td>
     </tr>
          <% rs = IngrController.getInEsaurimento();
             while(rs.next()) { %>
     <tr>
          <td><%= rs.getString("nome") %> </td>
          <td><%= rs.getString("unitaDiMisura") %></td>
          <td><%= rs.getString("disponibilita") %></td>
          <td><div align="center"><%= rs.getString("soglia") %></div></td>
          <td><div align="center"><input type="text" id="ingrediente<%= i %>" name="<%= rs.getString("nome") %>" value="0" onChange="selezionato(this)" /></div></td>
     </tr>
          <%i++; } %>
     <tr>
          <td> </td>
          <td> </td>
          <td> </td>
          <td><input type="hidden" name="totale_selezionati" value="0"/> </td>
          <td><input type="submit" name="acquista" value="Acquista" /></td>
     </tr>
</table>
</form>and this is the servlet's doPost method
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
          int i = Integer.parseInt(request.getParameter("totale_selezionati")); //nuber of item with quantity value > 0
          int j = 0, aux = 0; //j counts the number of items with quantity > 0 found, aux loops on each item id
          String[] ingrediente = new String;
          while (j < i) { //while stops when number of item with quantity value > 0 found is the same of the known number of those items
               if(Integer.parseInt(request.getParameter("ingrediente"+aux)) > 0) {
                    ingrediente[j] = request.getParameter("ingrediente"+aux); //takes the attribute value of the item, how to thake the name too?
                    j++;
                    aux++;
               else
                    aux++;               
          IngrController.aggiungiIngredienteMagazzino(ingrediente,i);
          RequestDispatcher dispatcher = request.getRequestDispatcher("/verificarimanenze.jsp");
          dispatcher.forward(request, response);
I can't use the items' names to loop on the form because the form is dinamically generated, I need to use the id attribute for that and then, take the name and value in the servlet... I can only take the value, I don't know how to take the name.
Edited by: Kumidan on Jul 24, 2008 9:16 AM
modified an instruction inside the while in the doPost method.