I've experienced the problem that I can't find solution for it anywhere. I've been writing a simple application in JavaFx and somehow any of my variables that I'd like to store simply can't be possible. I mean...yes it is possible but only as long as I stay in any method, after I leave method it simply lose any data that should be stored in global variables ;/ So here is how my code look like: First is my main Class where I start program. I open here first JavaFx window and create object to run DataBase Connection
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;
public class Main extends Application {
private static DBconnection connection;
@Override
public void start(Stage primaryStage) throws Exception{
Parent root = FXMLLoader.load(getClass().getResource("sample.fxml"));
primaryStage.setTitle("Main Menu");
primaryStage.setScene(new Scene(root, 300, 275));
primaryStage.show();
}
public static DBconnection getinstance(){
if(connection==null){
connection = new DBconnection();
}
return connection;
}
public static void main(String[] args) {
launch(args);
}
}
Next is my DBconnection Class (with some methods that are working quite ok...the only annoying thing is that I can't create connection once , but I must each time connect to database which is also a problem why I'm writing here:
import java.sql.*;
public class DBconnection {
public Statement stmt;
public Connection conn;
public ResultSet rs;
public String user,pass,dbURL;
public String userloginonline;
public DBconnection() {
conn = null;
stmt = null;
try {
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
dbURL = "jdbc:sqlserver://localhost\\sqlexpress:1433;databaseName=projektDB;";
user = "przemek";
pass = "przemek";
conn = DriverManager.getConnection(dbURL, user, pass);
} catch (SQLException ex) {
ex.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} finally {
try {
if (conn != null && !conn.isClosed()) {
conn.close();
}
} catch (SQLException ex) {
ex.printStackTrace();
}
}
}
public boolean createuser(String stringtosend) throws SQLException {
try {
conn = DriverManager.getConnection(dbURL, user, pass);
rs = conn.createStatement().executeQuery(stringtosend);
}catch (Exception e){
if(e.getMessage().equals("ERROR!") )
return false;
e.printStackTrace();
}
return true;
}
public boolean getlogpw(String login,String password) throws SQLException {
try {
conn = DriverManager.getConnection(dbURL, user, pass);
System.out.println("Login:"+userloginonline+" password:"+password);
userloginonline=login;
rs = conn.createStatement().executeQuery("Select * from Users where Username like \'"+login+"\'");
}catch (Exception e){
e.printStackTrace();
}
String LoginSql=" ",passwordsql=" ";
while(rs.next()){
LoginSql = rs.getString("Username");
passwordsql = rs.getString("Upassword");
}
if(LoginSql.equals(login)&&password.equals(passwordsql))
return true;
else
return false;
}
}
And the last important class is controller:
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.scene.Node;
import javafx.scene.control.PasswordField;
import javafx.scene.control.TextField;
import java.io.IOException;
import java.sql.SQLException;
public class Controller {
public String userloginonline;
Stageerr errorwindow;
DBconnection connection;
@FXML
private TextField login;
@FXML
private PasswordField pw1,pw2;
private String Slogin,Spw1,Spw2;
public void pressNewUser(ActionEvent event) throws IOException {
windowopener windowopener = new windowopener(event,"mainwindow.fxml","Create new user");
}
@FXML
public void newUserAccept(ActionEvent event) throws IOException, SQLException {
connection = Main.getinstance();
Slogin=login.getText();
Spw1=pw1.getText();
Spw2=pw2.getText();
if(Spw2.equals(Spw1) && !(Spw1.isEmpty()) &&!(Slogin.isEmpty())){
if(connection.createuser("INSERT INTO Users (Username,Upassword) values (\'"+Slogin+"\',\'"+Spw1+"\')")){
windowopener windowopener = new windowopener(event,"sample.fxml","Main Menu");
}
else errorwindow=new Stageerr(event,"ErrorWindow2.fxml");
}
else{
errorwindow=new Stageerr(event);
}
}
@FXML
public void authorizate(ActionEvent event) throws IOException, SQLException {
Slogin=login.getText();
Spw2=pw2.getText();
System.out.println(Slogin+" "+Spw2);
connection=Main.getinstance();
if(connection.getlogpw(Slogin,Spw2)){
Slogin=login.getText();
userloginonline=Slogin;
windowopener windowopener = new windowopener(event,"Corewindow.fxml","Log In");}
else{
errorwindow=new Stageerr(event);
}
}
public void About(ActionEvent event) throws IOException{
Withouthide withouthide = new Withouthide(event,"Help.fxml","About");
}
public void pressLogin(ActionEvent event) throws IOException {
windowopener windowopener = new windowopener(event,"Loginwindow.fxml","Log In");
}
public void presshide(ActionEvent event){ ((Node)(event.getSource())).getScene().getWindow().hide(); }
public void pressexit(ActionEvent event){
System.exit(0);
}
@FXML
public void pressremoveacc(ActionEvent event) throws IOException, SQLException {
Spw1=pw1.getText();
Spw2=pw2.getText();
System.out.println(userloginonline);
connection=Main.getinstance();
if(!(connection.getlogpw(userloginonline,Spw1))&&Spw1==Spw2){
windowopener windowopener = new windowopener(event,"mainwindow.fxml","Log In");}
else {
errorwindow = new Stageerr(event);
}
}
public void removeuserprocedure(ActionEvent event){
Withouthide withouthide = new Withouthide(event,"Removeacc.fxml","Remove User");
}
}
In controller class, generally I've put all the methods that all the fxml files reference to it. So whenever I press button in any window , it will do something. Here is the main problem also , when I want to store login for some longer (some kind of session), I'd like to store it at userloginonline (in authorizate method), but after it leaves that method it stores null string! Also I've tested same thing in DBconnection class , in method getlogpw but It also didn't store it for any longer time.
I'm also giving here 2 other classes but they are kinda ussles and propably not related to the problem:
import javafx.event.ActionEvent;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;
public class Stageerr {
Stage stageerr;
public Stageerr(ActionEvent event){
try {
FXMLLoader newframe = new FXMLLoader(getClass().getResource("ErrorWindow1.fxml"));
Parent root1 = (Parent) newframe.load();
stageerr = new Stage();
stageerr.setTitle("Error");
stageerr.setScene(new Scene(root1));
stageerr.show();
} catch(Exception e){
e.printStackTrace();
}
}
public Stageerr(ActionEvent event,String errorstr){
try {
FXMLLoader newframe = new FXMLLoader(getClass().getResource(errorstr));
Parent root1 = (Parent) newframe.load();
stageerr = new Stage();
stageerr.setTitle("Error");
stageerr.setScene(new Scene(root1));
stageerr.show();
} catch(Exception e){
e.printStackTrace();
}
}
}
And Windowopener...:
public class windowopener {
Stage mainstage;
public windowopener(ActionEvent event,String fxmlname,String name) throws IOException {
FXMLLoader newframe = new FXMLLoader(getClass().getResource(fxmlname));
Parent root1 = (Parent) newframe.load();
mainstage = new Stage();
mainstage.setTitle(name);
mainstage.setScene(new Scene(root1));
mainstage.show();
((Node)(event.getSource())).getScene().getWindow().hide();
}
}
And Withouthide class:
public class Withouthide {
Stage stageerr;
public Withouthide(ActionEvent event,String fxmlname,String name){
try {
FXMLLoader newframe = new FXMLLoader(getClass().getResource(fxmlname));
Parent root1 = (Parent) newframe.load();
stageerr = new Stage();
stageerr.setTitle(name);
stageerr.setScene(new Scene(root1));
stageerr.show();
} catch(Exception e){
e.printStackTrace();
}
}
}
I also didn't drop here code for fxml files since there are like 8 of them and they are not so really important (I think so, If it would help you to find an answer for that I'd drop the code here). Also I'd like to notice that I'm using InteliJ and I've found really similar problem here on stack but it was not solved (Cannot store Object in List<Object> with method from package?). Also If you see any bad programmers habits in my code I'd love to hear any advices ;) and Thanks for your time!
