Can a Java Applet use the printer?

Question

Can a Java Applet able to print out text/html easily to standard printer driver(s) (with all common platforms Win/Mac/Linux)?

Does it need to be signed?

Answer 1

To print you will either need to use Signed Applets or if an unsigned applet tries to print, the user will be prompted to ask whether to allow permission.

Here is some sample code for printing HTML using JEditorPane:

public class HTMLPrinter implements Printable{
    private final JEditorPane printPane;

    public HTMLPrinter(JEditorPane editorPane){
     printPane = editorPane;
    }

    public int print(Graphics graphics, PageFormat pageFormat, int pageIndex){
     if (pageIndex >= 1) return Printable.NO_SUCH_PAGE;

     Graphics2D g2d = (Graphics2D)graphics;
     g2d.setClip(0, 0, (int)pageFormat.getImageableWidth(), (int)pageFormat.getImageableHeight());
     g2d.translate((int)pageFormat.getImageableX(), (int)pageFormat.getImageableY());

     RepaintManager rm = RepaintManager.currentManager(printPane);
     boolean doubleBuffer = rm.isDoubleBufferingEnabled();
     rm.setDoubleBufferingEnabled(false);

     printPane.setSize((int)pageFormat.getImageableWidth(), 1);
     printPane.print(g2d);

     rm.setDoubleBufferingEnabled(doubleBuffer);

     return Printable.PAGE_EXISTS;
    }
}

Then to send it to printer:

HTMLPrinter target = new HTMLPrinter(editorPane);
PrinterJob printJob = PrinterJob.getPrinterJob();
printJob.setPrintable(target);
try{
    printJob.printDialog();
    printJob.print();
}catch(Exception e){
    e.printStackTrace();
}

Answer 2

In order to print, the security manager needs to allow it to access the printer. This means either signing the applet or, at least with recent versions of Sun's Java plugin, if an unsigned applet tries to print, the uesr will be prompted to ask whether to allow permission.