No parms passed to controlling servlet

Question

I want a page with an inputfield, 2 selectboxes and 1 (or more) submit-buttons. User MUST select a button before 'controlling servlet' is executed. (I mean, no action when 'enter' is used).
These are the 2 scenarios I tried:
Scenario (A)
When i put the <Form ...> tag at the top of my jsp and include inputfields and buttons, I get a 500_error when the cursor is in an inputfield and users presses 'enter'.
It seems that the parameters are not correctly passed to the 'controlling servlet'
However, when I
1) 'click' the Submit-button
or
2) 'click' outside this inputfield and then 'enter' or 'click' the Submit-button
the parms are correctly passed and 'controlling servlet' is correctly executed.
==>
<FORM action="/servlet/com.clipper.servlets.FQController" method=POST>
<td width="150" height="25" colspan="3" bgcolor="#FFFFFF">
     <INPUT size="15" type="text" maxlength="15" tabindex="1" name="agency" value="<%= ((String) session.getValue("sessionid.useragencycode")).trim() %>"></td>
<td width="600" height="25" bgcolor="#99CCFF" colspan="12">
<p align="left"><INPUT type=submit tabindex="5" name="action" value=" List "></p></td>
</FORM>
Scenario (B)
I changed code and do not have the 500_error when in inputfield but no parms are passed anymore.
This is the code
==>
<td width="150" height="25" colspan="3" bgcolor="#FFFFFF">
     <INPUT size="15" type="text" maxlength="15" tabindex="1" name="agency" value="<%= ((String) session.getValue("sessionid.useragencycode")).trim() %>"></td>
<FORM action="/servlet/com.clipper.servlets.FQController" method=POST>
<td width="600" height="25" bgcolor="#99CCFF" colspan="12">
<p align="left"><INPUT type=submit tabindex="5" name="action" value=" List "></p></td></FORM>
What is the correct implementation of this ?

Answer 1

1. your text field or any other form fields have to place between the <form> and </form> tag..
2. I don't know why you didn't get any paramter values, but you can write a function to list all the parameters that were in the request, call the function in the beginning of your control servlet.... Below is a sample...
     public static void listParameterValues(HttpServletRequest request) {
        Enumeration names = request.getParameterNames();
        if(names != null)  {
          String name="";
          while(names.hasMoreElements())  {
            name = (String)names.nextElement();
            String[] values = request.getParameterValues(name);
            if(values != null)  {
              for(int i=0; i<values.length; i++)  {
                System.out.println("listParameterValues(), " + name + "[" + i + "] = " + values);