title: request and button in post method
body: <p>In the post method to accept parameters "updateButton" and "reviewButton". If you register only <code>params = {"reviewButton"}</code> and click "reviewButton", the <code>request.getParameter ("reviewButton") == reviewButton</code>, and if the two parameters to register the getParameter returns null values.</p>
  
  <p>How do to determine which button is pressed?</p>
  
  <p>Page</p>
  
  <pre><code>  &lt;form  action="update" name ="updateCourseDTO" " action='&lt;@spring.url "/update" /&gt;' method="POST"/&gt;
      &lt;fieldset&gt;
        &lt;div class="control-group"&gt;
          &lt;label class="control-label"&gt;Name&lt;/label&gt;
          &lt;div class="controls"&gt;
  
          &lt;@spring.formInput "updateCourseDTO.name"   ""/&gt;
          &lt;@spring.showErrors  '&lt;br&gt;',"error" /&gt;
  
          &lt;/div&gt;
        &lt;/div&gt;
        &lt;div class="control-group"&gt;
          &lt;label class="control-label"&gt;Category&lt;/label&gt;
          &lt;div class="controls"&gt;
            &lt;@spring.formSingleSelect "updateCourseDTO.category" listCategories "" /&gt;
            &lt;@spring.showErrors '&lt;br&gt;',"error" /&gt;
          &lt;/div&gt;
        &lt;/div&gt;
  
        &lt;div class="control-group"&gt;
          &lt;label class="control-label"&gt;Description&lt;/label&gt;
          &lt;div class="controls"&gt;
            &lt;@spring.formInput "updateCourseDTO.description"/&gt;
            &lt;@spring.showErrors "updateCourseDTO.description","error" /&gt;
          &lt;/div&gt;
        &lt;/div&gt;
        &lt;div class="control-group"&gt;
          &lt;label class="control-label"&gt;Links&lt;/label&gt;
          &lt;div class="controls"&gt;
           &lt;@spring.formInput "updateCourseDTO.links"/&gt;
           &lt;@spring.showErrors "updateCourseDTO.links","error" /&gt;
          &lt;/div&gt;
        &lt;/div&gt;
        &lt;div class="control-group"&gt;
          &lt;label class="control-label"&gt;Minimal Subscribers&lt;/label&gt;
          &lt;div class="controls"&gt;
  
          &lt;@spring.formInput "updateCourseDTO.minSubscribers" ""/&gt;
          &lt;@spring.showErrors  'updateCourseDTO.minSubscribers',"error" /&gt;
          &lt;/div&gt;
        &lt;/div&gt;
         &lt;div class="control-group"&gt;
          &lt;label class="control-label"&gt;Minimal Attende&lt;/label&gt;
          &lt;div class="controls"&gt;
  
          &lt;@spring.formInput "updateCourseDTO.minAttendes" ""/&gt;
          &lt;@spring.showErrors  'updateCourseDTO.minAttendes',"error" /&gt;
          &lt;/div&gt;
        &lt;/div&gt;
        &lt;div class="form-actions" &gt;
          &lt;button id="updateButton" name="updateButton"   class="btn btn-primary" type="submit"  &gt;Update&lt;/button&gt;
         &lt;button id="reviewButton" name="reviewButton"    class="btn btn-warning" type="submit"  &gt;Review&lt;/button&gt;
        &lt;/div&gt;
      &lt;/fieldset&gt;
    &lt;/form&gt;
  </code></pre>
  
  <p>Controller</p>
  
  <pre><code>@RequestMapping(value = "/courses/{id}/update", method = RequestMethod.POST, params = { "updateButton", 
          "reviewButton" })
   public String updateCoursePost(Model model, HttpSession session,
          HttpServletRequest request, @PathVariable("id") Integer courseId,
          @Valid UpdateCourseDTO updateCourseDTO, BindingResult result)
          throws AddressException, Exception {
  
          if (request.getParameter("updateButton") != null) {}
          if (request.getParameter("reviewButton") != null) {}
  </code></pre>