java和jsp中的session有时不起作用

Question

我在设置属性时遇到问题，当我运行代码时有set属性功能，有时当我再次运行时，那是行不通的。代码运行顺利但是当我清除缓存时代码再次运行良好。属性会话值是否替换？我已经尝试session invalidate不行，我尝试删除属性也不行。如何解决这个问题？ 我的代码java1：

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    String report_name = "modules/kepesertaan/gaji/DaftarDataTarDiDataGajiInstansi.rpt";
    HttpSession session = request.getSession();

    // get value parameter from url
    String PKDCABANG = request.getParameter("PKDCABANG");
    String PKELSSBP = request.getParameter("PKELSSBP");
    String PKDSSBP = request.getParameter("PKDSSBP");
    String PBLTHGAJI = request.getParameter("PBLTHGAJI");
    String ID = request.getParameter("ID"); // ID User Login

    session.removeAttribute("report_name");
    session.removeAttribute("ID");
    session.removeAttribute("PKDCABANG");
    session.removeAttribute("PKDSSBP");
    session.removeAttribute("PKELSSBP");
    session.removeAttribute("PBLTHGAJI");

    try {
        // send value param1 dan param2 to jsp 
        session.setAttribute("report_name", report_name);
        session.setAttribute("ID", ID);
        session.setAttribute("PKDCABANG", PKDCABANG);
        session.setAttribute("PKELSSBP", PKELSSBP);
        session.setAttribute("PKDSSBP", PKDSSBP);
        session.setAttribute("PBLTHGAJI", PBLTHGAJI);

        // send request and to jsp file
        getServletContext().getRequestDispatcher("/CrystalReport-viewer.jsp").forward(request, response);
    } catch (Exception e) {
        System.out.println("Error: "+e);
        session.invalidate(); 
    }
}

Java2的：

代码与java1具有相同的属性会话。

JSP：

<%
    String report_name = (String) session.getAttribute("report_name");

    String ID = (String) session.getAttribute("ID");
    String P_KDCABANG = (String) session.getAttribute("P_KDCABANG");
    String P_KDSSBP = (String) session.getAttribute("P_KDSSBP");
    String P_BLTHGAJI = (String) session.getAttribute("P_BLTHGAJI");
    String P_KELSSBP = (String) session.getAttribute("P_KELSSBP");

    String PKDCABANG = (String) session.getAttribute("PKDCABANG");
    String PKELSSBP = (String) session.getAttribute("PKELSSBP");
    String PKDSSBP = (String) session.getAttribute("PKDSSBP");
    String PBLTHGAJI = (String) session.getAttribute("PBLTHGAJI");

    ReportClientDocument reportClientDoc = new ReportClientDocument();
    reportClientDoc.open(report_name, OpenReportOptions._openAsReadOnly);
    ParameterFieldController parameterFieldController = reportClientDoc
    .getDataDefController().getParameterFieldController();

    try{
        if (param1 != null){
            parameterFieldController.setCurrentValue("", "param1", param1);
        }
        if (param2 != null){
        parameterFieldController.setCurrentValue("", "param2", param2);
        }
        if (V_PANGKAT != null){
        parameterFieldController.setCurrentValue("", "V_PANGKAT", V_PANGKAT);
        }

        if (ID != null) {
            parameterFieldController.setCurrentValue("", "ID", ID);
        }
        if (P_KDCABANG != null) {
            parameterFieldController.setCurrentValue("", "P_KDCABANG", P_KDCABANG);
        }
        if (P_KDSSBP != null) {
            parameterFieldController.setCurrentValue("", "P_KDSSBP", P_KDSSBP);
        }
        if (P_BLTHGAJI != null) {
            parameterFieldController.setCurrentValue("", "P_BLTHGAJI", 
                    new SimpleDateFormat("yyyy-MM-dd").parse(P_BLTHGAJI));
        }
        if (P_KELSSBP != null) {
            parameterFieldController.setCurrentValue("", "P_KELSSBP", P_KELSSBP);
        }

        if (PKDCABANG != null) {
            parameterFieldController.setCurrentValue("", "PKDCABANG", PKDCABANG);
        }
        if (PKDSSBP != null){
            parameterFieldController.setCurrentValue("", "PKDSSBP", PKDSSBP);
        }
        if (PKELSSBP != null){
            parameterFieldController.setCurrentValue("", "PKELSSBP", PKELSSBP);
        }
        if (PBLTHGAJI != null){
            parameterFieldController.setCurrentValue("", "PBLTHGAJI", 
                    new SimpleDateFormat("yyyy-MM-dd").parse(PBLTHGAJI));
        }       
    }catch (Exception e){
        System.out.println("Errors: "+e);
    }

    CrystalReportViewer crystalReportPageViewer = new CrystalReportViewer();
    IReportSource reportSource = reportClientDoc.getReportSource();
    crystalReportPageViewer.setReportSource(reportSource);
    crystalReportPageViewer.setOwnPage(true);
    crystalReportPageViewer.processHttpRequest(request, response,
            application, null); 
%>

我尝试了java1代码并运行顺利，然后我运行java2代码并没有问题，但是当我再次运行java1时，是行不通的。在我的情况下，我创建水晶报告，并且参数未发送。错误显示：

  

找不到该字段.----错误代码：-2147213310错误代码   名：fieldNotFound

如何解决这个问题？会话集属性有时不起作用。