public class Login extends HttpServlet {
public static String user=null;
public static String password=null;
public static Connection con=null;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {



}

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

}
@Override
public void service(ServletRequest request, ServletResponse response) throws ServletException, IOException {
    getServletContext().getRequestDispatcher("/login.jsp").include(request, response);
    PrintWriter out=response.getWriter();
     response.setContentType("text/html");

     user=request.getParameter("user");
     password=request.getParameter("pass");
     if(user !=null || password!=null){
         try{
             Class.forName("oracle.jdbc.driver.OracleDriver");
             con = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1523:orcl",user,password);
             System.out.println("Conectare Reusita");
             javax.servlet.RequestDispatcher dispatcher = this.getServletContext().getRequestDispatcher("/Test");
             dispatcher.forward(request, response);

         }catch(Exception e){
             out.println("<p align="center">"+e.getMessage()+"</p>");
         }
     }

     out.close();
}
public static String getUser() {
    return user;
}
public static String getPassword() {
    return password;
}

public static String table_selected= null;
public static String[] col_selected= null;
 public static List <String> name_cols= new ArrayList<String>();

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

}

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

}

@Override
public void service(ServletRequest request, ServletResponse response) throws ServletException, IOException {

    getServletContext().getRequestDispatcher("/tables.jsp").include(request, response);

    PrintWriter out = response.getWriter();

    response.setContentType("text/html");

 try{
     String app = request.getParameter("app");
     col_selected=request.getParameterValues("q");

        if(col_selected!=null){

        for(int i=0;i<col_selected.length;i++){

            name_cols.add(col_selected[i]);
            }
        }

     System.out.println("cols:"+name_cols);

     if(app !=null){
         if(app.equals("Manual_select")){
            RequestDispatcher dispatcher = request.getRequestDispatcher("/select_data.jsp");
            dispatcher.forward(request, response);
         }

         if(app.equals("Show_cols")){

            if(col_selected!=null){
             RequestDispatcher rd = this.getServletContext().getRequestDispatcher("/cols_data.jsp");
                rd.include(request, response);

                name_cols.clear();

            }

         }

     }

     out.close();

 }catch(Exception e){
     e.printStackTrace();
 }

public static String join(List<String> list, String delim) {

    StringBuilder sb = new StringBuilder();

    String loopDelim = "";

    for(String s : list) {

        sb.append(loopDelim);
        sb.append(s);

        loopDelim = delim;
    }

    return sb.toString();
}

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

    getServletContext().getRequestDispatcher("/select_data.jsp").include(request, response);
    PrintWriter out=response.getWriter();

     response.setContentType("text/html");
     String select;
     select=request.getParameter("select");

     try{
         Class.forName("oracle.jdbc.driver.OracleDriver");
          Statement st = Login.con.createStatement();
         System.out.println("Connection established successfully!!");
         ResultSet rs = st.executeQuery(select);
         ResultSetMetaData rsmd = rs.getMetaData();

         int columnsNumber = rsmd.getColumnCount();
         System.out.println("row:"+columnsNumber);
         out.println("<br><table border=1 align="center">");

         out.println("<tr>");
            for(int i=1;i<=columnsNumber;i++){
                out.println("<th>"+rsmd.getColumnName(i)+"</th>");
            }
            out.println("</tr>");

         while(rs.next()){
             out.println("<tr>");
             for(int i=1;i<=columnsNumber;i++){
                 out.println("<td>"+rs.getString(i)+"</td>");
             }
             out.println("</tr>");

         }
         request.setAttribute("select",select);
         out.println("<table>");

     }catch(Exception e){

         out.println("<p align="center">"+e.getMessage()+"</p>");
     }
}


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

}


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

}