[FIXED] Dynamic dropdown returns a null from jsp

Issue

I have written a dropdown list which is populated by the database. This is my dropdown code in JSP file.

 <td>Category:</td>
 <%
  try {
      dbConnect dbConnect = new dbConnect();
      Connection currentCon = dbConnect.Connect();
      System.out.println("Connection sucess");
      String sql = "SELECT * FROM categories";
      PreparedStatement ps = currentCon.prepareStatement(sql);
      ResultSet rs = ps.executeQuery();%>
 <td><select name="category" class="form-control" required>
      <%
        while (rs.next()) {
           String cname = rs.getString("category_name");
           String id = rs.getString("category_id");
           System.out.println(id);
      %>
      <option value="<%= id%>"><%= cname%></option>
      <%
        }
      %>
      </select>
      <%
      } catch (SQLException sqe) {
            out.println(sqe);
      }
 %>
 </td>

The relevant servlet code is;

String id = request.getParameter("category");

In the sout of the dropdown in JSP it prints all the IDs in the category. But when it comes to the servlet it returns a null. How to resolve this issue?

Solution

I didn't find any <form> tag neither submit button in your code ,try below code :

    <td>Category:</td>
     <form method="post"  action="yourservleturl">//form tag for submitting data

         <%
          try {
              dbConnect dbConnect = new dbConnect();
              Connection currentCon = dbConnect.Connect();
              System.out.println("Connection sucess");
              String sql = "SELECT * FROM categories";
              PreparedStatement ps = currentCon.prepareStatement(sql);
              ResultSet rs = ps.executeQuery();%>
         <td><select name="category" class="form-control" required>
              <%
                while (rs.next()) {

              %>
              <option value="<%=rs.getString("category_id")%>"><%=rs.getString("category_name")%></option> // printing option values
              <%
                }
              %>
              </select>
              <%
              } catch (SQLException sqe) {
                    out.println(sqe);
              }
         %>
     <input type="submit" value="submit">///submit btn
  </form>
</td>

also get, dropdown value by String id = request.getParameter("category"); .it should worked .

Answered By - Swati