Java:将程序输出打印到物理打印机

Question

我是一个相对较新的程序员,所以这可能是一个非常简单的问题,但它让我有点难过..

我正在尝试将Java GUI的最终输出打印到打印机.现在,在我的GUI中,我有它,所以当你点击打印时,弹出窗口会显示可用打印机列表,并根据你选择的打印机,打印到该打印机.

但事实并非如此.我通过在互联网上搜索这个问题的解决方案获得了大部分代码,并找到了一些有希望的代码.但是,它打印出一个文件.所以我只是在我的方法中做的就是首先将输出写入文件,以便我可以使用相同的方法.

方法之前的一些事情:

1. 没有抛出任何错误或异常.

2. 我每次尝试创建的文件始终存在,并且具有正确的文本.

3. 打印到IS的打印机正在接收打印作业,它甚至认为它已经完成了.

如果我不得不猜测,我会认为我可能正在将输出写入File,因为打印机不会除外但不告诉我.无论如何,这段代码中有相当一部分我对此并不十分了解,所以请让我知道你能找到什么.

这是我的代码:

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

所以我找到了一种适合我的情况的方法,我想我会发布它的内容,以防它对任何人都有用.

该解决方案的基础是Java确实有自己的完全成熟(至少与我的相比)printDialog popUp,它比我需要的更多(页面布局编辑,预览等),所有你需要做的就是手工操作实现Printable的对象,在该对象中创建图形并绘制文档.

我只需要绘制我的输出字符串,这很容易完成,我甚至找到了一个StringReader,所以我可以天真地停止编写一个文件,只是为了让我的输出在BufferedReader中.

这是代码.有两个部分,我绘制图像的方法和类:

方法:

private void printToPrinter()
{
    String printData = CalculationTextArea.getText() + "\n" + SpecificTextArea.getText();
    PrinterJob job = PrinterJob.getPrinterJob();
    job.setPrintable(new OutputPrinter(printData));
    boolean doPrint = job.printDialog();
    if (doPrint)
    { 
        try 
        {
            job.print();
        }
        catch (PrinterException e)
        {
            // Print job did not complete.
        }
    }
}

这是打印文档的类:

public class OutputPrinter implements Printable 
{
    private String printData;

    public OutputPrinter(String printDataIn)
    {
    this.printData = printDataIn;
    }

@Override
public int print(Graphics g, PageFormat pf, int page) throws PrinterException
{
    // Should only have one page, and page # is zero-based.
    if (page > 0)
    {
        return NO_SUCH_PAGE;
    }

    // Adding the "Imageable" to the x and y puts the margins on the page.
    // To make it safe for printing.
    Graphics2D g2d = (Graphics2D)g;
    int x = (int) pf.getImageableX();
    int y = (int) pf.getImageableY();        
    g2d.translate(x, y); 

    // Calculate the line height
    Font font = new Font("Serif", Font.PLAIN, 10);
    FontMetrics metrics = g.getFontMetrics(font);
    int lineHeight = metrics.getHeight();

    BufferedReader br = new BufferedReader(new StringReader(printData));

    // Draw the page:
    try
    {
        String line;
        // Just a safety net in case no margin was added.
        x += 50;
        y += 50;
        while ((line = br.readLine()) != null)
        {
            y += lineHeight;
            g2d.drawString(line, x, y);
        }
    }
    catch (IOException e)
    {
        // 
    }

    return PAGE_EXISTS;
}
}

无论如何,这就是我如何解决这个问题!希望它对某人有用!