How do i print a return ArrayList?

Question

I have a method that generates and returns an ArrayList. How can i print the ArrayList from other classes?

    public ArrayList<Printer> selectAllePrinters() {
    ArrayList<Printer> printers = new ArrayList<>();
    try {
        Connection con = SimpleDataSource.getConnection();
        PreparedStatement stat = con.prepareStatement("SELECT * FROM printer;");
        ResultSet result = stat.executeQuery();
        while (result.next()) {
            Printer printer = new Printer();
            printer.setPrinterid(result.getString("printerid"));
            printer.setNaam(result.getString("printernaam"));
            printer.setAantalKl(result.getInt("aantalkleur"));
            printer.setAantalZw(result.getInt("aantalzwart"));
        }
        result.close();
        stat.close();
        return printers;
    } catch (SQLException e) {
        System.out.println(e);
        return null;
    }
}

Thanks in advance!

Also, with your code, you never add element to the ArrayList `printers`. So you're returning an empty Arraylist. — AntonH, Apr 03 '14 at 22:07
Do you want to add a list of Printers to it and then loop through it and print some strings from these Printer objects? — keyser, Apr 03 '14 at 22:11

score 0 · Accepted Answer · answered Apr 03 '14 at 22:07

0

In your method, add the new printers to the arraylist.

while (result.next()) {
    Printer printer = new Printer();
    printer.setPrinterid(result.getString("printerid"));
    printer.setNaam(result.getString("printernaam"));
    printer.setAantalKl(result.getInt("aantalkleur"));
    printer.setAantalZw(result.getInt("aantalzwart"));
    printers.add(printer); // Adds the printer to the arraylist.
}

Then print it.

System.out.println(selectAllePrinters());

answered Apr 03 '14 at 22:07

Anubian Noob

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Thank you very much! I have been blindly copying methods. I didn't even notice i was trying to print a empty ArrayList. – user3190748 Apr 03 '14 at 22:22
If you need more help, add a comment. – Anubian Noob Apr 03 '14 at 22:54

How do i print a return ArrayList?

1 Answers1