如何在servlet刷新时保留参数？

Question

我试图在servlet刷新后保留一个参数。我尝试了会议，但它不会工作。任何人都可以帮助我

@覆盖     protected void doGet（HttpServletRequest请求，HttpServletResponse响应）             抛出ServletException，IOException {

    String equip = request.getParameter("name");
        String qty = request.getParameter("qty");
        String equipId = null;
        //HttpSession session = request.getSession();
        //String itemId = (String) session.getAttribute("repId");
        String itemId = request.getParameter("repId");
                    HttpSession session = request.getSession();
                    session.setAttribute("id", itemId);
        //System.out.println(equip);
        //System.out.println(qty);
        System.out.println(itemId);


                    String itemId1 = (String)session.getAttribute("id");

                    System.out.println(itemId1);

        try {

            DB_Connection db = new DB_Connection();
            Connection conn = db.getDBconnection();

            Statement stmt1 = conn.createStatement();

            ResultSet rs1 = stmt1.executeQuery("SELECT id from equipment where name='"+equip+"'");

            while(rs1.next()){

                equipId=(String)rs1.getString("id");
                //System.out.println(equipId);
            }

            String insertString1 = "INSERT INTO used_equipment"
                    + "(item_id, eqp_id, qty) VALUES"
                    + "(?,?,?)";