Getting Parameters in a Servlet

Question

I can�t get the parameters of the doPost method of a Servlet, here is the code of the servlet called FileEvaluation:
     public void doPost(HttpServletRequest req, HttpServletResponse resp)
          throws ServletException, IOException {
          String fileName = "";
          String action = "";
          String tipoarch = null;
          InputStream fileIn = req.getInputStream();
          Enumeration params = req.getParameterNames();
          FileEvaluationLogic flogic = new FileEvaluationLogic("1");
          tipoarch = req.getParameter("tipoarch");
          System.out.println("tipoarch: "+tipoarch);
          if (tipoarch != null){
               FileScanner scanner = new FileScanner(fileIn, tipoarch);
               scanner.verify();
and this is the Html that calls it:
<form name="form1" method="post" action="FileEvaluation" ENCTYPE="multipart/form-data">
<table width="75%" border="0" align="center">
<tr>
<td width="27%"><font size="2" face="Verdana, Arial, Helvetica, sans-serif"><div align="right">Tipo de Archivo</div></font></td>
<td width="73%">
<select name="tipoarch" id="tipoarch">
<option value="1">CLIENTES</option>
<option value="2">PRESTAMO</option>
</select>
so, the variable tipoarch does not brings anything, anyone knows the reason?
Thanks.

Answer 1

Assuming, you're not trying to use a multipart form and that your html is correctly formatted,
this should work :
if ("a".equals.req.getParameter("name"))
out.println("filter success");
The key is that you never ever try to test equality between object using '==', because '==' is a reference test, not a equality test (you can have 2 strings that contains "a", they are equals but have different reference (two different physical objects).
One other interesting thing, is that you'd better test if "a" is equal to your parameter rather than the reverse. Note that, this way, you can spare the check on wether req.getParameter returns a null value.
For a global debugging code support help, insert the following code when you need to see what's coming in your request as parameters :
Enumeration e=req.getParameterNames();
while (e.hasMoreElements()) {
   String key=(String) e.nextElement();
   System.err.println("Request content : {"+key+"} => ["+req.geteParameter(key)+"]");