Java: Printing program output to a physical printer

Question

I am a relatively new programmer so this may be a really simple question to answer but its got me a bit stumped..

I'm trying to print my Java GUI's final output to a printer. Now, in my GUI, I have it so that when you hit print, a pop-up comes up with the list of available printers, and based on the one you select, it should print to that printer.

However it is not. I got most of my code by scouring the internet for solutions to this problem and found some promising code. However, it printed off of a File. So all I simply do in my method is write my output to a file first so that I can use the same methodology.

A couple things before the method:

1. There are no errors or exceptions thrown.

2. The File I attempt to create every time always exists, and with the correct text.

3. The printer I am printing to IS receiving the print job, it even thinks it has completed it.

If I had to guess, I would think I am perhaps writing the output to File in way that the Printer will not except but isn't telling me. Anyways, there is quite a bit in this code that I don't really have a firm understanding of so please let me know what you can find.

Here is my code:

private void printToPrinter()
    {

        File output = new File("PrintFile.txt");
        output.setWritable(true);
        //Will become the user-selected printer.
        Object selection = null;
        try 
        {
            BufferedWriter out = new BufferedWriter(new FileWriter(output));
            out.write(calculationTextArea.getText() + "\n" + specificTextArea.getText());
            out.close();

        }
        catch (java.io.IOException e)
        {
            System.out.println("Unable to write Output to disk, error occured in saveToFile() Method.");
        }
        FileInputStream textStream = null;
        try 
        {
            textStream = new FileInputStream("PrintFile.txt");
        }
        catch (java.io.FileNotFoundException e)
        {
            System.out.println("Error trying to find the print file created in the printToPrinter() method");
        }

        DocFlavor flavor = DocFlavor.INPUT_STREAM.AUTOSENSE;
        Doc mydoc = new SimpleDoc(textStream, flavor, null);

        //Look up available printers.
        PrintService[] printers = PrintServiceLookup.lookupPrintServices(flavor, null);

        if (printers.length == 0)
        {
            // No printers found. Inform user.
            jOptionPane2.showMessageDialog(this, "No printers could be found on your system!", "Error!", JOptionPane.ERROR_MESSAGE);
        }
        else
        {
            selection = jOptionPane2.showInputDialog(this, "Please select the desired printer:", "Print", 
                                                        JOptionPane.INFORMATION_MESSAGE, null, printers,
                                                        PrintServiceLookup.lookupDefaultPrintService()); 
            if (selection instanceof PrintService)
            {
                PrintService chosenPrinter = (PrintService) selection;
                DocPrintJob printJob = chosenPrinter.createPrintJob();
                try 
                {
                    printJob.print(mydoc, null);
                }
                catch (javax.print.PrintException e) 
                {
                    jOptionPane2.showMessageDialog(this, "Unknown error occured while attempting to print.", "Error!", JOptionPane.ERROR_MESSAGE);
                }
            }
        }
}

Answer 1

Create a JTextComponent (I suggest a JTextArea so you can use append()), and append what you need to the field. Do not display it on the view, it is simply a hidden field for printing purposes.

All JTextComponents have a print() method. Simply call hiddenTextArea.print() and the rest is handled for you.

        JTextArea hiddenTextArea = new JTextArea();
        for (String s : dataToPrintCollection) {
            hiddenTextArea.append(s + "\n");
        }

        try {
            hiddenTextArea.print();
        } catch (PrinterException e) {}