如何动态禁用和启用jetty请求日志？

 <Arg>

   <New class="org.eclipse.jetty.server.ServerConnector">

     <Arg name="server">

       <Ref refid="Server" />

     </Arg>

     <Arg>

       <Array type="org.eclipse.jetty.server.ConnectionFactory">

         <Item>

           <New class="org.eclipse.jetty.server.HttpConnectionFactory">

             <Arg name="config">

               <Ref refid="httpConfig" />

             </Arg>

           </New>

         </Item>

       </Array>

     </Arg>

     <Set name="host">

       <Property name="jetty.http.host" />

     </Set>

     <Set name="port">

       <Property name="jetty.http.port" default="8080" />

     </Set>

     <Set name="idleTimeout">

       <Property name="http.timeout" default="30000" />

     </Set>

     <!-- 启用请求日志 -->

     <Set name="requestLog">

       <New class="org.eclipse.jetty.server.NCSARequestLog">

         <Arg>

           <New class="java.io.File">

             <Arg>/path/to/logs/requests.log</Arg>

           </New>

         </Arg>

         <Set name="retainDays">90</Set>

         <Set name="append">true</Set>

         <Set name="extended">false</Set>

         <Set name="logCookies">false</Set>

         <Set name="logServer">false</Set>

         <Set name="logLatency">true</Set>

       </New>

     </Set>

   </New>

 </Arg>