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<@page contentType="text/html" pageEncoding="UTF-8"%>
<%@ page import ="java.sql.*" %>
<% Class.forName("com.mysql.jdbc.Driver"); %>
<% String idprod = request.getParameter("idprod");%>
<!DOCTYPE html>
<html>
    <head>
        <title>JSP Page</title>
    </head>
    <body>
        <%!
            public class Actor{
            String URL = "jdbc:mysql://localhost:3306/mysql";
             String USERNAME = "root";
            String PASSWD = "";
            String em="";
            String tempid="";
            Connection connection = null;
            PreparedStatement select= null;
            ResultSet resultSet = null;
             int a = 0;
            public Actor(String b){
            try{
            tempid=b;
            connection = DriverManager.getConnection(URL, USERNAME,PASSWD );
            select = connection.prepareStatement("SELECT quantity FROM products where id="+tempid );
            }
            catch (SQLException e){
                 e.printStackTrace();
            }
        }
         public int check(){
            try{
                resultSet = select.executeQuery();

            }
            catch (SQLException e){
                 e.printStackTrace();
            }
            return a;
            }
        public String getActors(){

            try{
                resultSet = select.executeQuery();
            while (resultSet.next()) {
            em = resultSet.getString("quantity");
            }
            } catch (SQLException e){
            e.printStackTrace();
        }
          return em;
    }
}
%>
        <%

            Actor actor = new Actor(idprod);
            String actors = actor.getActors();

         int iloscsztuk= Integer.parseInt(actors);
         int ilosckupionych =Integer.parseInt(request.getParameter("howmany"));
         int wynik=iloscsztuk-ilosckupionych;


     Class.forName("com.mysql.jdbc.Driver");
    Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/mysql",
            "root", "");
    Statement st = con.createStatement();
    //ResultSet rs;
    int i = st.executeUpdate("Update products set quantity="+wynik);
    if (i > 0) {
        //session.setAttribute("userid", user);
        out.println("Kupiono "+ilosckupionych+" sztuk produktu.");
        %>
        <form method="POST" action="index.jsp">
        <input  type = "submit" value = "Powrot" />
        </form>

     <%
    } else {
        response.sendRedirect("index.jsp");
    }

  %>

    </body>
</html>