登录限制尝试不适用于servlet

Question

如果用户登录失败，[<3次尝试后，我将尝试阻止其登录系统。] >>我为每个用户设置了一个“默认值”列，其默认int值为“ 3”，并且我尝试在每次尝试后将其递减，直到其变为0。

这里的问题是我的方法没有更新表上的值。

可能出什么问题了？请帮助。

这是我的

sql表：

CREATE TABLE user (
id bigint identity NOT NULL,
username varchar(50) NOT NULL,
password varchar(50) NOT NULL,
attempts int DEFAULT 3,
state varchar(50) DEFAULT 'Active',
PRIMARY KEY (id)
);

这是
登录servlet：

public class LoginCheck extends HttpServlet {



    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {



        String username = request.getParameter("username");
        String password = request.getParameter("password");


        /**
         *  verifies is the values are the same on the inputs
         *  creates session and redirects accordingly to answer
         *  blocks access after 3 failed attempts
         */



        if(CheckUser.Validation(username, password) && !BlockUser.SelectState(username))
        {
            HttpSession session = request.getSession();
            session.setAttribute("username", username);

            RequestDispatcher rs = request.getRequestDispatcher("profile.jsp");
            rs.forward(request, response);

        }  else if(CheckUser.Validation(username, password) && BlockUser.SelectState(username)) {

                String blocked = "This user is blocked";
                request.setAttribute("blocked", blocked);
                request.getRequestDispatcher("index.jsp").forward(request, response);   
                return;
            } 


        else if (!CheckUser.Validation(username, password) && !BlockUser.SelectState(username))
        {  
            //Here is where I call the method and try to decrement the number of attempts accordingly to the user that has been attempting

            BlockUser.Attempts(username);

            String error = "Wrong user or password. Try again.";
            request.setAttribute("error", error);
            request.getRequestDispatcher("index.jsp").forward(request, response);   


               }


        else {

            String state = "Inactive";

            BlockUser.Block(state, username);

            String blocked = "Exceeded max attempts. Account is now blocked.";
            request.setAttribute("blocked", blocked);
            request.getRequestDispatcher("index.jsp").forward(request, response);   
            }


    }

}

这是带有减少值的方法的类：

public class BlockUser {

    private static Connection con = null;
    private static PreparedStatement ps = null;
    private static ResultSet rs = null;



    public static void Attempts(String username) {


        try
          {con = DBConnectionManager.getConnection();

          if (con == null){
             System.out.println("Conexão falhada");

          }else{

              PreparedStatement sel = con.prepareStatement(
                         "SELECT * FROM user WHERE username = ? AND attempts = ?");

              sel.setString(1,username);   

             if(rs.next()) {

             rs.getInt("attempts");





            while(rs.getInt("attempts") != 0) {

                 PreparedStatement ps = con.prepareStatement(
                     "UPDATE user SET attempts = attempts - 1 WHERE username = ?");


            ps.setString(1,username);    
            ps.executeUpdate();
            ps.close();

            }}

            sel.close();
              }
          }
        catch (Exception e) {
             e.printStackTrace(System.out);


          }

    }

如果用户尝试3次后登录失败，我将尝试阻止其登录系统。我为每个用户设置了一个“默认值”列，其默认int值为“ 3”，并且我尝试在每个用户之后将其递减...

Answer 1

没有测试，但是尝试：

while(rs.getInt("attempts") != 0) {
   int value = 1;
   PreparedStatement ps = con.prepareStatement(
                     "UPDATE user SET attempts = attempts - ? WHERE username = ?");
   ps.setInt(1, value); 
   ps.setString(2, username); 
   ....
}

Answer 2

首先在select中进行Attempts(String username)查询是错误的，您已为?传递了attempts = ?但从未提供任何值。那么您将无法获得任何值并直接对其进行更新。相反，您的代码应如下所示：