Question

I’ve webapp1 which has a simple index.jsp

<form method="post" action="TestHarnessClass">
    SSN:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<input type="text" name="ssn" /> 
    <br />
    Username: <input type="text" name="un" />
    <br /><br />
    <input type="submit" value="Go to user contracts" />
</form>

And a backend servlet

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    String ssn = request.getParameter("ssn").trim();
    String username = request.getParameter("un").trim();
    request.setAttribute("ssn", ssn);
    request.setAttribute("un", username);
    response.sendRedirect(url);
}

And I can see that the address changed in the browser to the correct url with the un and ssn encoded as query parameters, I inspected the request parameters and it has the ssn and un:

But on the other web app I’ve the following code:

String ssn = request.getParameter("ssn");
String username = request.getParameter("un");

ssn and username are both null. What’s wrong with my code?

Answer 1

I think you should change your Servlet to

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws                                            
   ServletException, IOException {
      String ssn = request.getParameter("ssn").trim();
      String username = request.getParameter("un").trim();
      response.sendRedirect(url + "?ssn=" + ssn + "&un=" + un);
}