title: Losing request attributes when redirecting to HTTPS
body: <p>I am trying to implement login throught SSL on Tomcat.
  The login servlet is called IniciarSesion, so I add the following to the web.xml:</p>
  
  <pre><code>&lt;security-constraint&gt;
              &lt;web-resource-collection&gt;
                  &lt;web-resource-name&gt;Seguridad en Acceso&lt;/web-resource-name&gt;
                   &lt;url-pattern&gt;/IniciarSesion&lt;/url-pattern&gt;
              &lt;/web-resource-collection&gt;
              &lt;user-data-constraint&gt;
               &lt;transport-guarantee&gt;CONFIDENTIAL&lt;/transport-guarantee&gt;
              &lt;/user-data-constraint&gt;
  &lt;/security-constraint&gt;
  </code></pre>
  
  <p>The problem now is that when i try to get the input password by doing:</p>
  
  <pre><code>String nick=(String)req.getParameter("login");
  </code></pre>
  
  <p>This returns null, the request parameter is losing when redirirecting from http to https.</p>
  
  <p>How can i solve this?</p>