依赖于session的在线人数统计

淩亂°似流年 2022-07-13 08:47 191阅读 0赞

最近工作中遇到一个问题,

在做在线人数统计时.我们实现了HttpSessionListner,HttpSessionAttributeListener里面的attributedAdded()方法和attributeRemoved()的方法以及sessionDestroyed(),来操作一个map,将登陆的用户信息放入到map里面,用户退出时,再从map里面移除.

生产环境是在websphere上,出现了一个现象.很多天之前登录的用户还在在线人数里面,并且通过日志发现,此用户登录之后并没有做过任何业务操作.

第一步,重现问题.

开发环境是tomcat部署的,使用了一下四种方式产生的结果:

1.登录之后,点击注销,在线人数得到了更新

2.登录之后不做任何操作,等待session失效,在线人数得到了更新

3.登录之后关闭浏览器,等待session失效,在线人数得到了更新

4.登录之后,打开另一个浏览器,当前用户的在线人数信息得到了更新

在开发环境无法重现此问题,我们转战到生产环境:

1.登录一个用户,不做任何操作,等待到了session失效时间,在线人数没有更新\---经测试,进入sessionDestroyed()方法.没有进入attributeRemoveded()方法

2.登录一个用户,关闭浏览器,在人数没有得到更新,等待session到失效时间--经过测试,没有进入sessionDestroyed()方法.没有进入attributeRemoveded()方法

3.登录一个用户,点击注销,在线人数得到更新

4.登录一个用户,打开另一个浏览器再次登录,在线人数用户信息没有得到更新.

5.登录一个用户,不做任何操作,等待session失效后,此时在线人数没有得到更新.再次登录此用户,在线人数没有更新.点击注销,在线人数得到更新.

第二步,分析问题.

也就是说在websphere上面,只有主动调用invalidate(),进入监听方法,执行操作.

问题来了,当到了到了session失效时间之后,有三种可能性:

1.session并没有失效;

2.session失效了,但是没有进入监听执行sessionDestroyed()方法

3.session失效了,也进入了sessionDestroyed()方法,但是此时已经获取不到session了,所以无法执行移除操作.

测试发现

1.登录一个用户,不做任何操作\---经测试,进入sessionDestroyed()方法.没有进入attributeRemoveded()方法.在web.xml设置失效时间为2,但是时间是30min才执行的.

2.登录一个用户,关闭浏览器,等待session到失效时间 \---经过测试,没有进入sessionDestroyed()方法.没有进入attributeRemoveded()方法 liuqian15:50关闭浏览器在web.xml设置失效时间为2,但是时间是90min才执行的.

When timeout, server execute`request.getRemoteUser()` and re-login this user automatically, and sent a**New** JESSIONID to user browser by including below header.

Set-Cookie JSESSIONID=0000O0OB4W_4sxtn6elSmolMxI9:-1; Path=/; HttpOnly

3.不知道是那个用户进入sessionDestroyed()方法和attributeRemoveded()方法.但是sessionuser为空.并没有执行移除操作.

4.更多的情况是不进入这几个方法.

综上所述:session注意的点有如下:

1.覆盖机制

<table style="margin:0px auto 0px 0px; padding:0px; vertical-align:baseline; font-size:undefined; width:898px; clear:both; border-spacing:0px; font-family:Arial,sans-serif; border-bottom-width:0px"> 
 <thead style="margin:0px; padding:0px; vertical-align:baseline; font-size:undefined"> 
  <tr style="margin:0px; padding:0px; vertical-align:baseline; font-size:undefined; border-bottom-width:1px; border-bottom-style:solid; border-bottom-color:rgb(90,90,90); font-family:HelvBoldIBM,'Helvetica Neue',Arial,sans-serif"> 
   <td colspan="1" style="margin:0px; padding:8px 12px; vertical-align:baseline; font-size:undefined; border-bottom-width:1px; border-bottom-style:solid; border-bottom-color:rgb(17,17,17); width:50px"> 1.</td> 
   <td colspan="1" style="margin:0px; padding:8px 12px; vertical-align:baseline; font-size:undefined; border-bottom-width:1px; border-bottom-style:solid; border-bottom-color:rgb(17,17,17); width:268px"> <span style="margin:0px; padding:0px; border:0px; vertical-align:baseline; font-size:undefined">Server Level</span></td> 
   <td colspan="1" style="margin:0px; padding:8px 12px; vertical-align:baseline; font-size:undefined; border-bottom-width:1px; border-bottom-style:solid; border-bottom-color:rgb(17,17,17); width:39px"> <img src="http://www-01.ibm.com/support/docview.wss?uid=swg21163875&amp;aid=1" alt="" width="1" height="1" style="max-width:100%; margin:0px; padding:0px; border:0px; vertical-align:baseline; font-size:undefined; height:auto!important"></td> 
   <td colspan="1" style="margin:0px; padding:8px 12px; vertical-align:baseline; font-size:undefined; border-bottom-width:1px; border-bottom-style:solid; border-bottom-color:rgb(17,17,17); width:445px"> Lowest level</td> 
  </tr> 
 </thead> 
</table>

<table style="margin:0px auto; padding:0px; vertical-align:baseline; font-size:undefined; width:898px; clear:both; border-spacing:0px; font-family:Arial,sans-serif; border-bottom-width:0px"> 
 <thead style="margin:0px; padding:0px; vertical-align:baseline; font-size:undefined"> 
  <tr style="margin:0px; padding:0px; vertical-align:baseline; font-size:undefined; border-bottom-width:1px; border-bottom-style:solid; border-bottom-color:rgb(90,90,90); font-family:HelvBoldIBM,'Helvetica Neue',Arial,sans-serif; height:0px"> 
   <td colspan="1" style="margin:0px; padding:0px 12px; vertical-align:middle; font-size:undefined; border-bottom-width:0px; border-bottom-style:solid; border-bottom-color:rgb(17,17,17); width:50px; border-top-width:0px; height:0px"> &nbsp;</td> 
   <td colspan="1" style="margin:0px; padding:0px 12px; vertical-align:middle; font-size:undefined; border-bottom-width:0px; border-bottom-style:solid; border-bottom-color:rgb(17,17,17); width:268px; border-top-width:0px; height:0px"> 
    <div style="position:static!important; border:0px; vertical-align:baseline; font-size:1rem; height:0px; overflow:hidden; margin:0px!important; padding:0px!important"> 
     <span style="margin:0px; padding:0px; border:0px; vertical-align:baseline; font-size:undefined"></span> 
    </div> </td> 
   <td colspan="1" style="margin:0px; padding:0px 12px; vertical-align:middle; font-size:undefined; border-bottom-width:0px; border-bottom-style:solid; border-bottom-color:rgb(17,17,17); width:39px; border-top-width:0px; height:0px"> 
    <div style="position:static!important; border:0px; vertical-align:baseline; font-size:1rem; height:0px; overflow:hidden; margin:0px!important; padding:0px!important"> 
     <img src="http://www-01.ibm.com/support/docview.wss?uid=swg21163875&amp;aid=1" alt="" width="1" height="1" style="max-width:100%; margin:0px; padding:0px; border:0px; vertical-align:baseline; font-size:undefined; height:auto!important"> 
    </div> </td> 
   <td colspan="1" style="margin:0px; padding:0px 12px; vertical-align:middle; font-size:undefined; border-bottom-width:0px; border-bottom-style:solid; border-bottom-color:rgb(17,17,17); width:445px; border-top-width:0px; height:0px"> &nbsp;</td> 
  </tr> 
 </thead> 
 <tbody style="margin:0px; padding:0px; vertical-align:baseline; font-size:undefined"> 
  <tr style="margin:0px; padding:0px; vertical-align:baseline; font-size:undefined; background-color:inherit"> 
   <td style="margin:0px; padding:8px 12px; vertical-align:middle; font-size:undefined; border-top-width:0px; background-color:inherit"> 2.</td> 
   <td style="margin:0px; padding:8px 12px; vertical-align:middle; font-size:undefined; border-top-width:0px; background-color:inherit"> <span style="font-family:HelvBoldIBM,'Helvetica Neue',Arial,sans-serif; margin:0px; padding:0px; border:0px; vertical-align:baseline; font-size:undefined">Enterprise Application</span></td> 
   <td style="margin:0px; padding:8px 12px; vertical-align:middle; font-size:undefined; border-top-width:0px; background-color:inherit"> <img src="http://www-01.ibm.com/support/docview.wss?uid=swg21163875&amp;aid=1" alt="" width="1" height="1" style="max-width:100%; margin:0px; padding:0px; border:0px; vertical-align:baseline; font-size:undefined; height:auto!important"></td> 
   <td style="margin:0px; padding:8px 12px; vertical-align:middle; font-size:undefined; border-top-width:0px; background-color:inherit"> Overrides the Server Level if&nbsp;<span style="font-family:HelvBoldIBM,'Helvetica Neue',Arial,sans-serif; margin:0px; padding:0px; border:0px; vertical-align:baseline; font-size:undefined">Override</span>&nbsp;is selected</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; vertical-align:baseline; font-size:undefined; border-top-width:1px; border-top-style:solid; border-top-color:rgb(224,224,224)"> 
   <td style="margin:0px; padding:8px 12px; vertical-align:middle; font-size:undefined; border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); background-color:inherit"> 3.</td> 
   <td style="margin:0px; padding:8px 12px; vertical-align:middle; font-size:undefined; border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); background-color:inherit"> <span style="font-family:HelvBoldIBM,'Helvetica Neue',Arial,sans-serif; margin:0px; padding:0px; border:0px; vertical-align:baseline; font-size:undefined">Web Application</span></td> 
   <td style="margin:0px; padding:8px 12px; vertical-align:middle; font-size:undefined; border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); background-color:inherit"> <img src="http://www-01.ibm.com/support/docview.wss?uid=swg21163875&amp;aid=1" alt="" width="1" height="1" style="max-width:100%; margin:0px; padding:0px; border:0px; vertical-align:baseline; font-size:undefined; height:auto!important"></td> 
   <td style="margin:0px; padding:8px 12px; vertical-align:middle; font-size:undefined; border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); background-color:inherit"> Overrides the Server and Enterprise Application settings if<span style="font-family:HelvBoldIBM,'Helvetica Neue',Arial,sans-serif; margin:0px; padding:0px; border:0px; vertical-align:baseline; font-size:undefined">Override</span>&nbsp;is selected</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; vertical-align:baseline; font-size:undefined; border-top-width:1px; border-top-style:solid; border-top-color:rgb(224,224,224); background-color:inherit"> 
   <td style="margin:0px; padding:8px 12px; vertical-align:middle; font-size:undefined; border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); background-color:inherit"> 4.</td> 
   <td style="margin:0px; padding:8px 12px; vertical-align:middle; font-size:undefined; border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); background-color:inherit"> <span style="font-family:HelvBoldIBM,'Helvetica Neue',Arial,sans-serif; margin:0px; padding:0px; border:0px; vertical-align:baseline; font-size:undefined">Application Level (web.xml)</span></td> 
   <td style="margin:0px; padding:8px 12px; vertical-align:middle; font-size:undefined; border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); background-color:inherit"> <img src="http://www-01.ibm.com/support/docview.wss?uid=swg21163875&amp;aid=1" alt="" width="1" height="1" style="max-width:100%; margin:0px; padding:0px; border:0px; vertical-align:baseline; font-size:undefined; height:auto!important"></td> 
   <td style="margin:0px; padding:8px 12px; vertical-align:middle; font-size:undefined; border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); background-color:inherit"> Overrides Server, Enterprise Application, and Web Application settings</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; vertical-align:baseline; font-size:undefined; border-top-width:1px; border-top-style:solid; border-top-color:rgb(224,224,224)"> 
   <td style="margin:0px; padding:8px 12px; vertical-align:middle; font-size:undefined; border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); background-color:inherit"> 5.</td> 
   <td style="margin:0px; padding:8px 12px; vertical-align:middle; font-size:undefined; border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); background-color:inherit"> <span style="font-family:HelvBoldIBM,'Helvetica Neue',Arial,sans-serif; margin:0px; padding:0px; border:0px; vertical-align:baseline; font-size:undefined">Application Code</span></td> 
   <td style="margin:0px; padding:8px 12px; vertical-align:middle; font-size:undefined; border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); background-color:inherit"> <img src="http://www-01.ibm.com/support/docview.wss?uid=swg21163875&amp;aid=1" alt="" width="1" height="1" style="max-width:100%; margin:0px; padding:0px; border:0px; vertical-align:baseline; font-size:undefined; height:auto!important"></td> 
   <td style="margin:0px; padding:8px 12px; vertical-align:middle; font-size:undefined; border-top-width:1px; border-top-style:solid; border-top-color:rgb(221,221,221); background-color:inherit"> Overrides all other settings</td> 
  </tr> 
 </tbody> 
</table>

2.session失效后,调用监听方法的时间不确定性.

3.在was上,session失效时间的不确定性.

最终的解决办法是再实现一个过滤器,每次客户端发送请求是,先将所有session检查一遍,使用系统当前时间与最后一次操作时间相比,如果差大于session的有效时间.则主动调用session的失效方法.这样就会正常触发监听方法.达到人数统计的目的.

贴上代码:

package com.sunshine.monitor.comm.filter;
    
    import java.io.IOException;
    import java.util.Map;
    import java.util.Map.Entry;
    import java.util.concurrent.ConcurrentHashMap;
    import java.util.concurrent.atomic.AtomicInteger;
    import java.util.concurrent.locks.ReentrantLock;
    
    import javax.servlet.Filter;
    import javax.servlet.FilterChain;
    import javax.servlet.FilterConfig;
    import javax.servlet.ServletException;
    import javax.servlet.ServletRequest;
    import javax.servlet.ServletResponse;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.http.HttpSession;
    import javax.servlet.http.HttpSessionAttributeListener;
    import javax.servlet.http.HttpSessionBindingEvent;
    import javax.servlet.http.HttpSessionEvent;
    import javax.servlet.http.HttpSessionListener;
    
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    
    import com.sunshine.core.util.DateUtil;
    import com.sunshine.monitor.comm.bean.UserSession;
    import com.sunshine.monitor.comm.startup.AppSystemListener;
    import com.sunshine.monitor.system.manager.bean.SysUser;
    
    public class OnlineUserListener
    		implements
    			HttpSessionListener, HttpSessionAttributeListener, Filter {
    	
    	private Logger log = LoggerFactory.getLogger(OnlineUserListener.class);
    	
    	/**
    	 * 用户Session对象
    	 */
    	public static final String USER_SESSION_NAME = "userSession";
    
    	/**
    	 * 在线人数
    	 */
    	public static AtomicInteger lineCount = new AtomicInteger(0);
    	
    	private final ReentrantLock lock = new ReentrantLock();
    	
    	public final static String LISTENER_NAME = "_login";
    	
    	private static volatile Map<String, SysUser> users = new ConcurrentHashMap<String, SysUser>();
    	private static volatile Map<String, HttpSession> sessions = new ConcurrentHashMap<String, HttpSession>();
    	
    	/**
    	 * 需要人工添加属性_login,触发此方法
    	 */
    	@Override
    	public void attributeAdded(HttpSessionBindingEvent hbe) {
    		if(LISTENER_NAME.equals(hbe.getName())){
    			// 用户登录成功后,将HttpSession存储到一个map.
    			HttpSession session = hbe.getSession();
    			//System.out.println(hbe.getName() + "-HttpSessionAttributeListener(attributeAdded)...........");
    			SysUser user = (SysUser) hbe.getValue();
    			String yhdh = user.getYhdh();
    			final ReentrantLock _lock = this.lock;
    			_lock.lock();
    			try {
    				boolean flag = users.containsKey(yhdh);
    				users.put(yhdh, user);
    				sessions.put(yhdh, session);
    				if(!flag){
    					lineCount.addAndGet(1); // 累加器
    				}
    				System.out.println(yhdh + "-HttpSessionAttributeListener(attributeAdded)..........." + lineCount.intValue());
    			} finally {
    				_lock.unlock();
    			}
    		}
    		
    	}
    	
    	/**
    	 * 需要人工删除属性_login,触发此方法
    	 */
    	@Override
    	public void attributeRemoved(HttpSessionBindingEvent hbe) {
    		if(LISTENER_NAME.equals(hbe.getName())){
    			System.out.println(hbe.getName() + "-HttpSessionAttributeListener(attributeRemoved)...........");
    			SysUser user = (SysUser) hbe.getValue();
    			if(user == null)
    				return;
    			String yhdh = user.getYhdh();
    			final ReentrantLock _lock = this.lock;
    			_lock.lock();
    			try{
    				if(users.containsKey(yhdh)){
    					users.remove(user.getYhdh());
    					sessions.remove(user.getYhdh());
    					lineCount.decrementAndGet();
    					System.out.println(yhdh + "-HttpSessionAttributeListener(attributeRemoved)..........." + lineCount.intValue());
    				}
    			} finally {
    				_lock.unlock();
    			}
    		}
    	}
    
    	@Override
    	public void attributeReplaced(HttpSessionBindingEvent hbe) {
    		
    	}
    	
    	/**
    	 * 会话创建时执行
    	 */
    	@Override
    	public void sessionCreated(HttpSessionEvent he) {
    		/*HttpSession session = he.getSession();
    		UserSession userSession = (UserSession)session.getAttribute(USER_SESSION_NAME);
    		if(userSession != null){
    			final ReentrantLock _lock = this.lock;
    			_lock.lock();
    			//System.out.println(he.getSource()+ "-HttpSessionListener(sessionCreated)...........");
    			SysUser user = userSession.getSysuser();
    			if(user == null) return;
    			String yhdh =user.getYhdh();
    			try{
    				boolean flag = users.containsKey(yhdh);
    				if(!flag){
    					users.put(yhdh, user);
    					lineCount.addAndGet(1); // 累加器
    //					System.out.println(yhdh+ "-HttpSessionListener(sessionCreated)..........." + lineCount.intValue());
    				}
    			} finally {
    				_lock.unlock();
    			}
    		}*/
    	}
    	/**
    	 * 会话消毁执行
    	 */
    	@Override
    	public void sessionDestroyed(HttpSessionEvent he) {
    		HttpSession session = he.getSession();
    		UserSession userSession = (UserSession)session.getAttribute(USER_SESSION_NAME);
    		if(userSession != null){
    			log.info(he.getSource()+ "-HttpSessionListener(sessionDestroyed)...........");
    			SysUser user = userSession.getSysuser();
    			String yhdh = user.getYhdh();
    			final ReentrantLock _lock = this.lock;
    			_lock.lock();
    			try{
    				if(users.containsKey(yhdh)){
    					users.remove(user.getYhdh());
    					sessions.remove(user.getYhdh());
    					lineCount.decrementAndGet();
    					log.info(yhdh+ "-HttpSessionListener(sessionDestroyed)..........." + lineCount.intValue());
    				}
    			} finally {
    				_lock.unlock();
    			}
    		}
    	}
    
    	public static Map<String, SysUser> getUsers() {
    		return users;
    	}
    	
    	public static void setUsers(Map<String, SysUser> vaildUsers) {
    		users = vaildUsers;
    	}
    	
    	public static Map<String, HttpSession> getSessions() {
    		return sessions;
    	}
    	
    	public static void setSessions(Map<String, HttpSession> vaildSessions) {
    		sessions = vaildSessions;
    	}
    
    	@Override
    	public void destroy() {
    		
    		
    	}
    
    	@Override
    	public void doFilter(ServletRequest arg0, ServletResponse arg1,
    			FilterChain arg2) throws IOException, ServletException {
    		//HttpServletRequest request = (HttpServletRequest)arg0;
    		//HttpSession session = request.getSession(false);
    		for(Entry<String, HttpSession> entry : sessions.entrySet()){
    			HttpSession ss = entry.getValue();
    			if(ss!=null){
    				log.info(ss.getId());
    				log.info("系统当前时间:"+DateUtil.longToTime(System.currentTimeMillis()));
    				log.info("最后一次操作时间:"+DateUtil.longToTime(ss.getLastAccessedTime()));
    				// 系统当前时间-最后操作时间>则强制使session失效.
    				if((System.currentTimeMillis() - ss.getLastAccessedTime())>ss.getMaxInactiveInterval()*1000){// session timeout
    					log.info("强制使session:"+ss.getId()+"失效...");
    					ss.invalidate();
    				}
    			}else{
    				System.out.println("This session is null....");
    			}
    		}
    		arg2.doFilter(arg0, arg1);
    	}
    
    	@Override
    	public void init(FilterConfig arg0) throws ServletException {
    		// TODO Auto-generated method stub
    		
    	}
    }