200分求SessionCounter
import javax.servlet.*;
import javax.servlet.http.*;
public class SessionCounter implements HttpSessionListener
{ private static int activeSessions = 0;
public void sessionCreated(HttpSessionEvent se)
{ activeSessions++; }
public void sessionDestroyed(HttpSessionEvent se)
{ if(activeSessions > 0) activeSessions--; }
public static int getActiveSessions()
{ return activeSessions; }
}
问题:
1、在什么时候会响应sessionDestroyed?
2、这样计算在线人数不准确怎么办?