ebanksessionlistener.java

我在加拿大学习的一个比较复杂的在线银行程序.

package com.ebusiness.ebank.security;

/**
 * <p>Title: </p>
 * <p>Description:  This class implements HttpSessionListenner.
 *                  It will notify eBank system to remove user from
 *                  UserContainer when the user's session is being destroyed.
 *                  A user session will be destroyed when either the user's session
 *                  is timed out or the user performs logout action
 * </p>
 * <p>Copyright: Copyright (c) 2005</p>
 * <p>Company: eBusiness Inc., All right reserved</p>
 * @author unascribed
 * @version 1.0
 */

import java.util.Date;

import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;

import org.apache.log4j.Logger;
import org.apache.log4j.MDC;

import com.ebusiness.ebank.util.Constants;

public class EbankSessionListener
    implements HttpSessionListener
{
    private Logger log = Logger.getLogger(this.getClass());

    /**
     *  When a user login and create a new HttpSession, this method will be automatically called.
     */
    public void sessionCreated(HttpSessionEvent sessionEvent)
    {
        //log.info("A new session was created.");
    }

    /**
     *  When a user logout or the user's session is expired, this method will be automatically called.
     *  After the method is called, the user's profile will be removed from the UserContainer
     */
    public void sessionDestroyed(HttpSessionEvent sessionEvent)
    {
        Date startTime = new Date();
        HttpSession session = sessionEvent.getSession();
        String userID = (String)session.getAttribute(Constants.USER_ID);

        UserContainer.removeUser(userID); //remove the user from the container

        MDC.put(Constants.USER_ID, userID);
        MDC.put(Constants.ACTION, "Sign Out");
        MDC.put(Constants.ENTITY, "eBusiness Online Banking");
        MDC.put(Constants.STATUS, "Successful");
        MDC.put(Constants.FAILED_REASON, "");

        Date endTime = new Date();
        long duration = endTime.getTime()- startTime.getTime();
        MDC.put(Constants.DURATION, Long.toString(duration));
        log.audit("");
    }
}