基于tomcat获取在线用户数

https://blog.csdn.net/smallnetvisitor/article/details/84697505

需求：

统计某应用的在线用户数

实现方案：

1.基于session监听(复杂麻烦)

2.基于org.apache.catalina.Manager(依赖)

采用第二种的实现如下：

1.  
   private int activeUserNumber(HttpServletRequest request) {
2.  
   int activeSessions = 0;
3.  
   try {
4.  
   if (request instanceof RequestFacade) {
5.  
   Field requestField = request.getClass().getDeclaredField(
6.  
   "request");
7.  
   requestField.setAccessible(true);
8.  
   Request req = (Request) requestField.get(request);
9.  
   org.apache.catalina.Context context = req.getContext();
10.  
    Manager manager = context.getManager();
11.  
    activeSessions = manager.getActiveSessions();
12.  
    }
13.  
    } catch (Exception e) {
14.  
    e.printStackTrace();
15.  
    }
16.  
    log.info("users:{}", activeSessions);
17.  
    return activeSessions;
18.  
    }
19.  
     
20.  
    private List<Usr> activeUsers(HttpServletRequest request) {
21.  
    List<Usr> list = new ArrayList<Usr>();
22.  
    try {
23.  
    if (request instanceof RequestFacade) {
24.  
    Field requestField = request.getClass().getDeclaredField(
25.  
    "request");
26.  
    requestField.setAccessible(true);
27.  
    Request req = (Request) requestField.get(request);
28.  
    org.apache.catalina.Context context = req.getContext();
29.  
    Manager manager = context.getManager();
30.  
     
31.  
    Session[] sessions = manager.findSessions();
32.  
    for (Session session : sessions) {
33.  
    //your
34.  
    }
35.  
    }
36.  
    } catch (Exception e) {
37.  
    e.printStackTrace();
38.  
    }
39.  
    log.info("users:{}", list);
40.  
    return list;
41.  
    }