getting servlet param values from filter

Question

I am sending a post request from a form to a redirect servlet. The servlet then write a form to its response (getWriter) object. This form contains a number of hidden fields. I use javascript to submit this form (the javascript is written to the response object as well). The target of this form is another servlet.

Now, I'm writing a filter to intercept the hidden parameters I'm sending over to the other servlet (on another server). However when I do: String[] values = req.getParameterValues(name);

I get no values for any of the parameters I put in the string "name". I cannot change the architecture of the code (not mine). I just need to get the parameters sent by the first servlet in my filter, but I keep getting null. Any help is greatly appreciated.

my first servlet code:

    PrintWriter out = response.getWriter();
    out.println("<html>");
    out.println("<head><title>redirectServlet</title></head>");

    out.println("<body>");
    out.println("<form name=\"go\" method=\"post\" action=\"http://" + 
                remotehost + "/somerep/someservlet?\">");



    out.println("<input type=hidden name=userid value=" + conn + "> ");

    out.println("<input type=hidden name=paramform value=no> ");
    out.println("<input type=hidden name=nonblocksql value=no> ");
    out.println("<input type=hidden name=recursive_load value=no> ");
    out.println("<input type=hidden name=job_seq_id value=" + jobId + ">");
    out.println("<input type=hidden name=destype value=cache> ");
    out.println("<input type=hidden name=desformat value=pdf> ");
    out.println("</form> ");

    out.println("<script language=\"JavaScript\" type=\"text/javascript\"> ");
    out.println("document.getElementById('go').submit();");
    out.println("</script>");

    out.println("</body>");
    out.println("</html>");

Matt, I've updated my question with some code. This servlet will submit the form using javascript to the specified remote servlet. I want to intercept this request using a servlet filter on the remote servlet's machine/server. — berto77
– berto77, Commented Oct 31, 2011 at 20:52
You really should consider using JSPs for the HTML parts, and Servlets for the logic parts. — Philipp Reichart
– Philipp Reichart, Commented Oct 31, 2011 at 20:58
Out of curiosity, why aren't you just submitting an HTTP POST on behalf of the browser? The current implementation is kind of a WTF. — Matt Ball
– Matt Ball, Commented Oct 31, 2011 at 21:02
@MattBall I thought the same believe me! My job is just to write the filter (or to get my job done, i need to write the filter). I have no idea why they chose to do it like this...@Pilipp true its better that way, but I'm working within an established project in a framework called ADF (sux!). Anyways, thanks for your replies. — berto77
– berto77, Commented Nov 1, 2011 at 14:11

Matt Ball · Accepted Answer · 2011-10-31 20:57:01Z

1

There is no element with ID go in that generated HTML. Change

out.println("<form name=\"go\" method=\"post\" action=\"http://" + 
// to
out.println("<form id=\"go\" method=\"post\" action=\"http://" +

answered Oct 31, 2011 at 20:57

Matt Ball

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1 Comment

berto77 Over a year ago

Good catch, however this works in terms of calling the remote servlet...I'll change and see if it makes a difference. Thanks!: just tried..seems like it doesn't make a difference in IE. I can get the headers fine, but not the hidden parameters.

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