Jetty currently has two levels of request statistic collection:

In addition to these, subclasses of the SessionHandler and DefaultSessionCache classes optionally can collect session statistics.

AbstractConnector, SessionHandler and DefaultSessionCache statistics are turned off by default and must either be configured manually for each instance or turned on via JMX interface. The StatisticsHandler is not included in default Jetty configuration, and needs to be configured manually.

Detailed statistics on connection duration and number of requests are only collated when a connection is closed. The current and maximum number of connections are the only "live" statistics.

The following example shows how to turn on connector statistics in Jetty xml. This example comes from within jetty-http.xml.

  <Call name="addConnector">
    <Arg>
      <New class="org.eclipse.jetty.server.ServerConnector">
        <Arg name="server"><Ref refid="Server" /></Arg>
        <Arg name="factories">
          <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.host" /></Set>
        <Set name="port"><Property name="jetty.http.port" default="8080" /></Set>
        <Set name="idleTimeout">30000</Set>
        <!-- Enable Connection Statistics -->
        <Call name="addBean">
          <Arg>
              <New id="ConnectionStatistics" class="org.eclipse.jetty.io.ConnectionStatistics"/>
          </Arg>
        </Call>
      </New>
    </Arg>
  </Call>

To collect request statistics a StatisticsHandler must be configured as one of the handlers of the server. Typically this can be done as the top level handler, but you may choose to configure a statistics handler for just one context by creating a context configuration file. You can enable the StatisticsHandler by activating the stats modules on the command line.

$ java -jar {$jetty.home}/start.jar --add-to-start=stats

Alternately, if you are making multiple changes to the Jetty configuration, you could include statistics handler configuration into your own Jetty xml configuration. The following fragment shows how to configure a top level statistics handler:

    <Get id="oldhandler" name="handler" />
  <Set name="handler">
    <New id="StatsHandler" class="org.eclipse.jetty.server.handler.StatisticsHandler">
      <Set name="handler"><Ref refid="oldhandler" /></Set>
    </New>
  </Set>

Session handling is built into Jetty for any servlet or webapp context. Detailed statistics on session duration are only collated when a session is closed. The current, minimum, and maximum number of sessions are the only "live" statistics. The session statistics are enabled by default and do not need to be configured.