Question

我正在尝试设置一个Java应用程序，它将文档发送到打印机。作为起点，我只是尝试打印一个字符串。我已经到了应用程序无错误运行的地步，并且我已经证明PrintService可以打印我的请求，但是从打印机中什么也不会吐出来。

我一直在遵循以下有关如何设置Java应用程序以将内容发送到打印机的指南。

从这些我有以下代码：

public String print(String name, String message) throws PrintException, IOException {
        PrintService[] printServices = PrintServiceLookup.lookupPrintServices(null, null);
        PrintService service = null;
        boolean printed = false;
        for (PrintService printer : printServices) {
            if (printer.getName().contains(name)) {
                System.out.println("Printing to : " + printer.getName());

                DocFlavor flavor = DocFlavor.BYTE_ARRAY.AUTOSENSE;
                Doc doc = new SimpleDoc(message.getBytes(), flavor, null);

                PrintRequestAttributeSet  pras = new HashPrintRequestAttributeSet();
                pras.add(new Copies(1));
                pras.add(MediaSize.ISO.A4.getMediaSizeName());
                pras.add(Sides.DUPLEX);

                PrintService[] services =
                                PrintServiceLookup.lookupPrintServices(flavor, null);
                boolean found = false;
                for(PrintService s : services) {
                    System.out.println(s.getName());
                    if (s.equals(printer)) {
                        found = true;
                    }
                }
                if (!found) {
                    System.out.println("Unable to find a compatible printer");
                }

                DocPrintJob job = printer.createPrintJob();
                PrintJobWatcher pjw = new PrintJobWatcher(job);

                job.print(doc, pras);
                pjw.waitForDone();


                // send FF to eject the page
                Doc docff = new SimpleDoc("\f".getBytes(), flavor, null);
                DocPrintJob jobff = printer.createPrintJob();
                pjw = new PrintJobWatcher(jobff);
                jobff.print(docff, null);
                pjw.waitForDone();

                printed = true;
                break;
            }
        }

        return printed ? "Document has been printed" : "Failed to print document";
    }


    class PrintJobWatcher {
        boolean done = false;

        PrintJobWatcher(DocPrintJob job) {
          job.addPrintJobListener(new PrintJobAdapter() {
            public void printJobCanceled(PrintJobEvent pje) {
              allDone();
            }
            public void printJobCompleted(PrintJobEvent pje) {
              allDone();
            }
            public void printJobFailed(PrintJobEvent pje) {
              allDone();
            }
            public void printJobNoMoreEvents(PrintJobEvent pje) {
              allDone();
            }
            void allDone() {
              synchronized (PrintJobWatcher.this) {
                done = true;
                System.out.println("Printing done ...");
                PrintJobWatcher.this.notify();
              }
            }
          });
        }
        public synchronized void waitForDone() {
          try {
            while (!done) {
              wait();
            }
          } catch (InterruptedException e) {
          }
        }
      }

我在控制台中的输出如下：

Printing to : My Printer XYZ
My Printer XYZ
Microsoft XPS Document Writer
Microsoft Print to PDF
Fax
Printing done ...
Printing done ...

任何人都可以帮助我了解为什么这导致什么都没发生吗？

javax.print api-打印机没有任何输出

0 个答案: