title: Which return type use in spring mvc in @RequestMapping method?
body: <p>I know in spring mvc in @Controller class in @RequestMapping method I can return</p>
  
  <ol>
  <li>String </li>
  <li>Model </li>
  <li>ModelAndView</li>
  </ol>
  
  <p>I don't understand differencies between these actions.
  Can you to explain me it?</p>