title: difference betweern return plain modelandview and return a redirect modelandview
body: <p>I have just learnt Spring MVC webflow. I am confused with this:</p>
  
  <pre><code>return new ModelAndView("test");
  return new ModelAndView("redirect:test");
  </code></pre>
  
  <p>Is the redirect one just like <code>response.sendRedirect()</code>?
  And I just check the Spring reference, actually, the <code>return new RedirectView()</code> does the same as <code>response.sendRedirect()</code>. So what's difference between these three?</p>