Question

这是我的servlet，它创建会话并将accessCount存储到当前会话

@WebServlet("/ShowSession.do")
public class ShowSession extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws IOException, ServletException {
        HttpSession session = request.getSession();

        String header;
        Integer accessCount  = (Integer)request.getAttribute("accessCount");

        if(accessCount == null){
            accessCount = new Integer(0);
            header = "Welcome New Comer";
        }else{
            header = "Welcome Back!";
            accessCount = new Integer(accessCount.intValue() + 1 );
        }

        //Integer is immutable data structure. so we cannot
        //modify the old one in-place,Instead, you have to
        //allocate a new one and redo setAttribute
        session.setAttribute("accessCount", accessCount);
        session.setAttribute("heading", header);
        RequestDispatcher view = getServletContext().getRequestDispatcher("/showsession.jsp");
        view.forward(request, response);
    }
}

这是打印出该会话内容的视图

<body>
    <%
        HttpSession clientSession = request.getSession();
        String heading = (String) clientSession.getAttribute("heading");
        Integer accessCount = (Integer) clientSession
                .getAttribute("accessCount");
    %>
    <h1>
        <center>
            <b><%=heading%></b>
        </center>
    </h1>
    <table>
        <tr>
            <th>Info type</th>
            <th>Value</th>
        <tr>
        <tr>
            <td>ID</td>
            <td><%=clientSession.getId()%></td>
        </tr>
        <tr>
            <td>Creation Time</td>
            <td><%=new Date(clientSession.getCreationTime())%></td>
        </tr>
        <tr>
            <td>Time of last Access</td>
            <td><%=new Date(clientSession.getLastAccessedTime())%></td>
        </tr>
        <tr>
            <td>Number OF Access</td>
            <td><%=accessCount%></td>
        </tr>
    </table>
</body>

问题在于即使我已经访问了很多次，它仍然会返回一个accessCount == 0，

我在localhost访问：8080 / someFolderName / ShowSession.do

Answer 1

您从请求中获得了accessCount初始值。你应该从会议中查看。

//Bad!
Integer accessCount  = (Integer)request.getAttribute("accessCount");
//Good (maybe)
Integer accessCount  = (Integer)session.getAttribute("accessCount");

View不会读取当前会话

1 个答案: