从Servlet更新jsp不起作用

Question

我有两个 servlet BookSaleAuction 和 MemberServlet 以及一些用于插入和更新为 index.jsp 和 MemberDetailUpdate.jsp 的 jsp 文件和
在 MemberDetailUpdate.jsp 中

<form method= "post" action="/booksaleauction">
  UserName : <input type="text" name="name" value="<%=editname%>">
  Address : <input type="text" name="address" value="<%=address%>">
  Contact : <input type="tel" name="contactNo" value="<%=contact%>">
  Email : <input type="email" name="email" value="<%=editemail%>">
  <input type="hidden" name="id" value="<%=editID%>">
  <input type="hidden" name="formAction" value="update">

  <input type="submit" name="Update">
</form>

在 BookSaleAuctionServlet 中

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    String form = request.getParameter("formAction");
    System.out.print(form);
}

在 MemberServlet 中

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        System.out.print("into member servlet ");
        String name = request.getParameter("name");
        String address = request.getParameter("address");
        String contact = request.getParameter("contactNo");
        String email = request.getParameter("email");
        String id = request.getParameter("id");

        try {
            Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            System.out.println("Class not found " + e);
        }
        System.out.println("JDBC Class found");
        Connection con = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        Statement st = null;

        try {
            con = DriverManager.getConnection("jdbc:mysql://localhost/logins", "root", "");
            String sql = "UPDATE members SET username=?, email=?, contact=?, address=? WHERE id=?";
           // ps = con.prepareStatement("UPDATE Users SET password=?, fullname=?, email=? WHERE id=id");
            PreparedStatement statement = con.prepareStatement(sql);
            statement.setString(1, name);
            statement.setString(2, email);
            statement.setString(3, contact);
            statement.setString(4, address);


            int rowsUpdated = statement.executeUpdate();
            if (rowsUpdated > 0) {
                System.out.println("An existing user was updated successfully!");
            }

        } catch (SQLException e) {
            System.out.println("SQL exception occured" + e);
        }
        try {
            request.getRequestDispatcher("MemberDetail.jsp").forward(request, response);

        } catch (Exception e) {
            System.out.println("SQL exception occured" + e);
        }

在两个 servlet 中，只要在 jsp 中完成更新，就没有任何进一步的操作正在完成。即使我将操作和方法更改为从另一个 servlet BookSaleAuction 运行，它也不适用于表单。请帮助我不知道我犯了什么错误。

Answer 1

你应该检查这个链接，

http://www.mkyong.com/jdbc/how-to-connect-to-mysql-with-jdbc-driver-java http://www.mkyong.com/tutorials/jdbc-tutorials/

我已经完成了我的 servlet 示例， https://github.com/oguzpamuk/Dynamic-Web-Project-Example