取得在線session數量

CLASS:
public class CountSessionListener implements HttpSessionListener
{
 public static int number = 0;
 
 
 public void sessionCreated(HttpSessionEvent event)
 {
  number ++;
 }

 
 public void sessionDestroyed(HttpSessionEvent event)
 {
  number --;
 }
 
}

web.xml

<listener>
 <listener-class>com.config.CountSessionListener</listener-class>
</listener>