jsp修改表单后，servlet中request.getParameter（）获取的数据为空

问题遇到的现象和发生背景

问题相关代码，请勿粘贴截图

 <form action="${pageContext.request.contextPath}/productupdateservlet" method="post" >
            <div class="list">
                <span>商品名称:</span>
                <input class="listinput" type="text" name="name" required="required" placeholder="请输入商品名称..." value=${pname} />
            </div>
            <div class="list">
                <span>商品款式:</span>
                <input class="listinput" type="text" name="style" required="required" placeholder="请输入商品款式..."
                       value="${ptype}" />
            </div>
            <div class="list">
                <span>商品价格:</span>
                <input class="listinput" type="number" name="money" step="1000.00" required="required"
                       placeholder="请输入商品价格..." value=${pprice} />
            </div>

            <div class="list">
                <span>商品库存:</span>
                <input class="listinput" type="number" name="number" required="required" placeholder="请输入商品库存..."
                       value=${pnumber} />
            </div>
            <div class="list">
                <span>上架时间:</span>
                <input class="listinput" type="date" name="date" required="required" placeholder="请输入上架时间..." value=${pdate} />
            </div>
            <div class="submit">
                <button class="" type="submit">更新</button>

                <button class="reset" type="reset" onclick="window.history.back();">取消</button>

            </div>

        </form>

sevlet代码

String change_pname = request.getParameter("pname");
            DateFormat df = new SimpleDateFormat("yyyy-MM-dd");
            String change_ptype = request.getParameter("ptype");
            System.out.println(request.getParameter("pprice"));
            Double change_pprice=0.0;
            if (request.getParameter("pprice")==null) {

            }else{
                change_pprice = Double.parseDouble(request.getParameter("pprice"));
            }
//            Double change_pprice = Double.parseDouble(request.getParameter("pprice"));
            System.out.println(request.getParameter("pnumber"));
            Integer change_pnumber=0;
            if (request.getParameter("pnumber")==null) {
            }else{
                change_pnumber = Integer.parseInt(request.getParameter("pnumber"));
            }
//            Integer change_pnumber = Integer.parseInt(request.getParameter("pnumber"));
            System.out.println(request.getParameter("pdate"));
            Date change_pdate=null;
            if (request.getParameter("pdate")==null) {
            }else{
                change_pdate = df.parse(request.getParameter("pdate"));
            }
//            Date change_pdate = df.parse(request.getParameter("pdate"));

运行结果及报错内容

不报错，但为空，或者我定义的0

我的解答思路和尝试过的方法

我想要达到的结果