Java jsp发送servlet空变量[重复]

Question

此问题已经在这里有了答案：

How to transfer data from JSP to servlet when submitting HTML form（4个答案）

关闭14分钟前。

所以我的.jsp文件中有这段代码

<table border="0" style="width:400px;">
    <form class="Credentials" action="SellerServlet" method="post">
        <tr style="height: 40px">method
            #User name
            <td style="width: 20%; text-align: right;">
                <label for="Name"><b>Name:</b></label>
            </td>
            <td>
                <input type="text" id="Name" name="Name" required>
            </td>
        </tr>

        #Surname
        <tr style="height: 40px">
            <td style="width: 20%; text-align: right;" >
                <label for="surname"><b>Surname:</b></label>
            </td>
            <td>
                <input type="text" id="Surname" name="Surname" required>
            </td>
        </tr>

        #Username
        <tr style="height: 40px">
            <td style="width: 20%; text-align: right;">
                <label for="username"><b>Username:</b></label>
            </td>
            <td>
                <input  type="text" id="username" name="user" required>
            </td>
        </tr>
        <tr style="height: 40px">
            <td style="width: 20%; text-align: right;" >
                <label for="password"><b>Password:</b></label>
            </td>
            <td>
                <input type="password" id="password" name="pass" required>
            </td>
        </tr>


        #User Type
        <tr style="height: 40px">
            <td style="width: 20%; text-align: right;" >
                <label for="type"><b>Type:</b></label>
            </td>
            <td>
                <input type="text" id="type" placeholder="Client" readonly>
            </td>
        </tr>

        #User Program
        <tr style="height: 40px">
            <td style="width: 20%; text-align: right;"  >
                <label for="program"><b>Program:</b></label>
            </td>
            <td>
                <select style="width: 150px" id="program" name="program" >
                    <option value="" selected disabled hidden>Επιλέξτε πρόγραμμα</option>
                    <option>asdfs</option>
                    <option>asdfas</option>
                    <option>asfdas</option>
                </select>
            </td>
        </tr>

        #Submit Button
        <tr style="height: 100px;">
            <td colspan="2" style="width: 50%">
                <center>
                    <button type="submit" name="Register" >Register</button>
                </center>
            </td>
        </tr>
    </form>
</table>

而且我的servlet代码是

@WebServlet(name = "SellerServlet" , urlPatterns = {"/SellerServlet"})
public class SellerServlet extends HttpServlet {
    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        String registerButton = request.getParameter("register");
        if(registerButton!=null){
            //request.getRequestDispatcher("/index.jsp").forward(request, response);
            String Username=request.getParameter("user");
            String Password=request.getParameter("pass");
            System.out.println(Username+Password);
            Seller CreateClient= new Seller();
            CreateClient.CreateClientAccount(Username,Password);
        }
    }
}

这里的servlet应该做的是将2个值（用户和传递）传递给Seller类的对象，以便以后对它们进行某些操作，我没有包括以下部分，因为它起作用了，它只是获取了值两者都为零，我现在已经摔了两个小时，试图找出原因

如果需要：使用Java 14和tomcat 9

Answer 1

在您拥有的jsp代码中

Answer 2

此变量与什么有关？