Display selected item from Listbox

Question

hi,
i get <h:selectOneListbox> value from database, now i want to know which item is selected in the listbox
my JSP code is
<h:selectOneListbox binding="#{DynamicListBean.std_list_lbx}" id="std_list_lbx" immediate="true"
                            onchange="common_timeoutSubmitForm(this.form, 'std_list_lbx');" required="true" size="5"
                            style="height: 312px; left: 168px; top: 192px; position: absolute; width: 216px" value="#{DynamicListBean.selectedCategory1}" valueChangeListener="#{DynamicListBean.std_list_lbx_processValueChange}">
                            <f:selectItems id="listbox1SelectItems1" value="#{DynamicListBean.items1}"/>
                        </h:selectOneListbox>Java code is public String getSelectedCategory1() {    
        return selectedCategory1;
    public void setSelectedCategory1(String selectedCategory1) {
        this.selectedCategory1 = selectedCategory1;
public void std_list_lbx_processValueChange(ValueChangeEvent vce) {
        connection();
        int n1 = 0;
        String a = "";
        if (con != null) {
            try {
                stmt = con.createStatement();
                String query = "select std_id, std_name from std_detail";
                rs = stmt.executeQuery(query);
                String iddata = "";
                if (rs != null) {
                    while (rs.next()) {
                        iddata = rs.getString("std_id");
                  //      System.out.println(rs.getInt("std_id"));
                        stmt1 = con.createStatement();
                        String query1 = "select chpt_detail from chapter_detail right outer join std_detail on chapter_detail.std_id = std_detail.std_id where chapter_detail.std_id = " + iddata + " ";
                        String data3 = "";
                        rs1 = stmt1.executeQuery(query1);
                        if (rs1 != null) {
                            while (rs1.next()) {
                                data3 = rs1.getString("chpt_detail");
                                chpt_lst_lbx.setValue(data3);
                                dList2.add(data3);
                            stmt1.close();
                            rs1.close();
                            List selectItems = new ArrayList();
                            Iterator it = dList2.listIterator();
                            while (it.hasNext()) {
                                String label = (String) it.next();
                                chpt_lst_lbx.setValue(label);
                                selectItems.add(new SelectItem(label));
                            items2 = (SelectItem[]) selectItems.toArray(new SelectItem[0]);
                    stmt.close();
                    rs.close();
                    con.close();
            } catch (Exception e) {
                System.out.println("Sorry failed to display values from the database table. " + e.getMessage());
                System.out.println(e);
    }any idea or suggestion tell me

Answer 1

You usually use the property behind value="#{DynamicListBean.selectedCategory1}" for that. But in your case you'll need the vce.getNewValue() as the valueChangeListener is been invoked before the property is been set.
Having said that, your code is terrible. Please read on about the DAO pattern. Further on, did you know that you can also just use List<SelectItem> instead of SelectItem[] as f:selectItems value?
If you want to populate child menu's, you may find this article useful to avoid future and painful problems: [http://balusc.blogspot.com/2007/10/populate-child-menus.html].