我正在尝试通过servlet检查数据库中的数据，但是html页面没有读取servlet页面..

错误：

  

原始服务器找不到目标的当前表示形式   资源或不愿透露存在。

我的登录页面：

<form action="validate" method="Post">
    User name:
    <br>
    <input type="text" name="username">
    <br>
    User password:
    <br>
    <input type="password" name="psw">
    <input type="submit" value="Submit">
</form>

我的Serlvlet代码：

protected void doPost(HttpServletRequest request,HttpServletResponse response)
        throws ServletException,IOException {
    response.SetContenttype("text/html");
    String uname = request.getParameter("username");
    String password = request.getParameter("psw");

    Class.forName("com.mysql.jdbc.Driver");
    Connection Con = DriverManager.getconnection("jdbc:mysql://localhost:3306/students","root","1234");
    PreparedStatement pstmt = Con.prepareStatement("SELECT * FROM data WHERE username = ? AND password = ?");
    pstmt.setString(1,uname);
    pstmt.setString(2,password);
    ResultSet rs = pstmt.executeQuery();
    if (rs.next()) {
        System.out.println("record found");
        RequestDispatcher rd = request.getRequestDispatcher("Stu.jsp");
        rd.forward(request,response);
    } else {
        System.out.println("record not found");
        RequestDispatcher rd = request.getRequestDispatcher("Login.html");
        rd.forward(request,response);
    }
    rs.close();
    pstmt.close();
    Con.close();

    doGet(request,response);
}