title: how to remove tags with jsoup but keep given tags
body: <p>How to remove all tags except <code>&lt;p&gt;</code> and <code>&lt;img&gt;</code> with jsoup?</p>
  
  <pre><code>&lt;div&gt;
    &lt;p&gt;hello world
      &lt;span&gt;good&lt;/span&gt;
      &lt;img src="/src/img/beauty.jpg"/&gt;
      welcome
    &lt;/p&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>Should become</p>
  
  <pre><code>&lt;p&gt;hello world
      good
      &lt;img src="/src/img/beauty.jpg"/&gt;
      welcome
    &lt;/p&gt;
  </code></pre>