title: Using JSTL url and param tag
body: <p>I have a list of sizes that a user can choose from, is it posssible to build a parameter based on a link a user clicks? </p>
  
  <p>For example, there is this following html</p>
  
  <pre><code>    &lt;ul class="options list-unstyled"&gt;
                  &lt;h4 class="m_9"&gt;Select a Size&lt;/h4&gt;
                  &lt;li&gt;&lt;a href="?size=s"&gt;S&lt;/a&gt;&lt;/li&gt;
                  &lt;li&gt;&lt;a href="?size=m"&gt;M&lt;/a&gt;&lt;/li&gt;
                  &lt;li&gt;&lt;a href="?size=l"&gt;L&lt;/a&gt;&lt;/li&gt;
                  &lt;li&gt;&lt;a href="?size=xl"&gt;XL&lt;/a&gt;&lt;/li&gt;
                  &lt;div class="clearfix"&gt;&lt;/div&gt;    
              &lt;/ul&gt;
  </code></pre>
  
  <p>And then there is this in my controller</p>
  
  <pre><code> @RequestMapping(value = "/addprodtocart", method = RequestMethod.POST)
  public ModelAndView cart(@RequestParam("productId") Integer id, @RequestParam("size") String size) {}
  </code></pre>
  
  <p>Disregarding the productId for now I would like the size requestParam to be equal to which ever one the user clicked.  Basically a temp variable in jstl that changes whenever a new size is selected and then the form below will be passed the built url (basically whichever size the user selected)</p>
  
  <pre><code> &lt;form  method='POST' action="${url }" &gt;  
                 &lt;input type="hidden" name="${_csrf.parameterName}" value="${_csrf.token}"/&gt;  
                   &lt;input type="submit" value="add to cart" title=""&gt;
                &lt;/form&gt;
  </code></pre>
  
  <p>Is this possible? and how? thank  you                                                                                                                                                                                                                                                                      </p>