title: Filter by class name in log4j2
body: <p>I am using log4j2 and I don't know how I can filter by class name. I have tried with RegexFilter but it only filters the text message. In old log4j was enough with tag 'filter'</p>
  
  <pre><code>&lt;filter class="aaaa.bbbb.cccc.ClassName"&gt;
  </code></pre>
  
  <p>Somebody knows how to do now?</p>
  
  <p>Thank you in advance!</p>
  
  <p>Update:</p>
  
  <p>Ok, I did it! I need to define a logger and set the class name in attribute 'name':</p>
  
  <pre><code>&lt;loggers&gt;
      &lt;logger name="aaaa.bbbb.cccc.ClassName" additivity="false" level="info"&gt;
          &lt;appender-ref ref="RollingFile" /&gt;
      &lt;/logger&gt;
      &lt;root level="error"&gt;
          &lt;appender-ref ref="RollingFile" /&gt;
      &lt;/root&gt;
  &lt;/loggers&gt;
  </code></pre>