title: How to deal with the url with value like root=, the parameter with key and without value?
body: <p>I have the problem just like the title. I know there is a <code>@RequesetParam</code> in spring mvc, it has a parameter <code>required=false</code>. But it failed when try to use it.</p>
  
  <p>Actually I found the <code>@RequestParam</code> is useless. According to my trying, It always be O.K. using <code>@RequestParam(value="root", required=true)</code> where the URL is with/without <code>value=some value except blank</code>. 
  So, I don't know what totally the <code>required=true</code> is. Then, whichever the <code>required=false</code> or <code>required=true</code>is, it throws exception with URL parameter like <code>...&amp;root=</code>.</p>
  
  <p>And my HandlerMapping &amp; AdapterMapping are RequestMappingHandlerMapping and RequestMappingHandlerAdapter</p>
  
  <p>the version of spring mvc is 3.2.4</p>
  
  <p>Please tell me what's going on with the spring mvc?</p>
  
  <p>Thanks advance:)</p>