当用户在指定时间内不活动时将用户重定向到特定页面

Question

我想对我的 servlet 进行编程，以在用户处于非活动状态 10 分钟后阻止会话而不关闭并将用户重定向到页面 sessionlocked.jsp。

我测试了这段代码，但它不起作用。

session.setMaxInactiveInterval(10*60);
if (request.getSession(false) == null) {
    response.sendRedirect(url);
}

我怎样才能做到这一点？

Answer 1

如documentation;

setMaxInactiveInterval(int interval)

Specifies the time, in seconds, between client requests before the servlet container will invalidate this session.

所以setMaxInactiveInterval方法不符合您的需求，它使会话无效。

要向用户显示锁定的页面，您有两种选择；

第一；

Use filters to check session time and if time is over redirect to lockedpage otherwise reset time.

public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
    HttpSession session = ((HttpServletRequest) request).getSession(false);
    if (session == null) {
        // ((HttpServletRequest) request).getSession(true);
        // redirect to logout or anywhere you want, to create a session
        return;
    }
    // Check if filter also work for sessionlocked.jsp
    if (((HttpServletRequest) request).getRequestURL().toString().contains("sessionlocked")) {
        chain.doFilter(request, response); // no need to check sessionlocked
        return;
    }
    long lastAccessTime = session.getLastAccessedTime();
    long tenMinuteAsMilisecond = 10 * 60 * 1000;
    if (lastAccessTime + tenMinuteAsMilisecond > (new Date()).getTime()) {
        chain.doFilter(request, response); // session still not locked
    } else {
        ((HttpServletResponse) response).sendRedirect("sessionlocked.jsp");
    }
}

第二次（除了第一次，因为第一次尝试在服务器端控制）；

Use javascript to count down and when time is over, redirect user to the locked page.

 window.onload = function() {
        setInterval(function() {
            window.location.replace("/sessionlocked.jsp");
              }, 600000);
    }

如果只需要servlet；（当用户与 servlet 交互时）

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    HttpSession session = request.getSession(false);
    if (session == null) {
        request.getSession(true);
        // redirect to logout or anywhere you want, to create a session
        return;
    }
    long lastAccessTime = session.getLastAccessedTime();
    long tenMinuteAsMilisecond = 10 * 1000;// to test lock time set to 10 seconds
    if (lastAccessTime + tenMinuteAsMilisecond > (new Date()).getTime()) {
        response.getOutputStream().print("Session not locked" + i++);
        // TODO for not locked code
    } else {
        response.getOutputStream().print("Session locked");
         //redirect to sessionlocked.jsp
    }
}

Servlet输出（锁定时间设置为10秒）；

当用户在指定时间内不活动时将用户重定向到特定页面

Redirect user to specific page when user is inactive for a specified time

session

redirect

servlets

servlet-filters