我有一个非常简单的 Servlet 和一个非常简单的 HttpSessionListener:
@WebServlet("/HelloWorld")
public class HelloWorld extends HttpServlet {
private static final long serialVersionUID = 1L;
@Override
public void init(ServletConfig config) throws ServletException {
super.init(config);
getServletContext().setAttribute("applicationHits", new AtomicInteger(0));
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("get");
((AtomicInteger) request.getServletContext().getAttribute("applicationHits")).incrementAndGet();
((AtomicInteger) request.getSession(true).getAttribute("sessionHits")).incrementAndGet();
request.setAttribute("requestHits", 0);
getServletContext().getRequestDispatcher("/view/HelloWorld.jsp").forward(request, response);
}
}
@WebListener
public class SessionListener implements HttpSessionListener {
public SessionListener() {
}
public void sessionCreated(HttpSessionEvent arg0) {
System.out.println("session listener");
arg0.getSession().setAttribute("sessionHits", new AtomicInteger(0));
}
public void sessionDestroyed(HttpSessionEvent arg0) {
}
}
My HttpSessionListener.sessionCreated()
方法永远不会被调用(没有日志输出),我最终得到一个NullPointerException
在我调用 getSession() 的线路上
((AtomicInteger) request.getSession(true).getAttribute("sessionHits")).incrementAndGet();
request.setAttribute("requestHits", 0);
我尝试打电话getSession()
没有true
以及,但同样的问题。
我不明白——不是吗@WebListener
注释足以调用我的侦听器吗? Eclipse 甚至将其显示为监听器Deployment Descriptor/Listeners
.