java - java中作业完成后返回主函数

Question

我这里有代码:对于主类:

 PrintingOperation printnew = new PrintingOperation();
 printnew.PrintingOperation(newfile);

 System.out.println("The file is to be deleted and will return from the start");

 File toDelete = listOfFiles[0]; //This output the full path of the file to be deleted
 System.out.println(toDelete); //I confirmed that it is a full path
 toDelete.delete(); //The problem occurs here -> It does not delete the file
 System.out.println("The file is deleted");

对于打印服务:

   public String PrintingOperation(String file_name){

    System.out.println("The file name is: " + file_name);
    PrintService printService = PrintServiceLookup.lookupDefaultPrintService();
    PdfDecoder decodePdf = new PdfDecoder(true);
    try {
    decodePdf.openPdfFile(file_name);
    FontMappings.setFontReplacements();

 } catch (Exception e) {
    //...
 }

//Setting the attributes
    PrintRequestAttributeSet attributeSet = new HashPrintRequestAttributeSet();
    JobName jobName = new JobName(file_name, null);
    attributeSet.add(jobName);
    attributeSet.add(new Copies(1)); //NUMBER OF COPIES
    attributeSet.add(MediaSizeName.ISO_A4); // Paper size : ISO_A4 or NA_LEGAL
    attributeSet.add(Chromaticity.COLOR); //COLOR or MONOCHROME
    decodePdf.setPrintAutoRotateAndCenter(false);

    PrintService[] services = PrintServiceLookup.lookupPrintServices(DocFlavor.SERVICE_FORMATTED.PAGEABLE, attributeSet);
    for(PrintService s : services) {
      System.out.println(s.getName());
    }
        PrintService printingDevice = null; 
    for(PrintService s : services) {
      if(s.getName().equals("Brother MFC-5890CN Printer")) { //Change it to the printer available
           printingDevice = s; 
      }
    }
    PdfBook pdfBook = new PdfBook(decodePdf, printingDevice, attributeSet);
    SimpleDoc doc = new SimpleDoc(pdfBook, DocFlavor.SERVICE_FORMATTED.PAGEABLE, null);
    DocPrintJob printJob = printingDevice.createPrintJob();
    JobCompleteMonitor monitor = new JobCompleteMonitor();
    printJob.addPrintJobListener(monitor);
    try {
      printJob.print(doc, attributeSet);
    } catch (PrintException e) {
        //...
    }
    monitor.waitForJobCompletion();


    System.out.println("Exiting printing process");      
    return null;
}
private static class JobCompleteMonitor extends PrintJobAdapter {

    private boolean completed = false;

    @Override
    public void printJobCanceled(PrintJobEvent pje) {
        signalCompletion();
    }

    @Override
    public void printJobCompleted(PrintJobEvent pje) {
        signalCompletion();
    }

    @Override
    public void printJobFailed(PrintJobEvent pje) {
        signalCompletion();
    }

    @Override
    public void printJobNoMoreEvents(PrintJobEvent pje) {
        signalCompletion();
    }

    private void signalCompletion() {

synchronized (JobCompleteMonitor.this) {

        completed = true;

        JobCompleteMonitor.this.notify();
}

  }

public synchronized void waitForJobCompletion() {

  try {

while (!completed) {

    wait();

}

  } catch (InterruptedException e) {

 }


}
}

一旦程序到达

printJob.print(doc, attributeSet)

打印机将开始运行并打印文档。但它会自动返回main方法，不会删除正在打印的文件。我放置了等待打印作业完成的函数，但它仍然返回到 main 方法，而不等待打印作业完成。

问题是，如何在打印完成后才返回main方法并在打印完成后删除文件？我使用了system.exit()，但我不希望程序终止，但我只想在打印作业完成后返回到main方法来执行main方法中剩余的代码行。我希望有人能在这方面帮助我。

注意:我还查看了 return 和 system.exit() 之间的区别以及暂停。我还检查了为了删除该文件，我需要完整路径才能删除它，我发现我已经放置了完整路径。

Answer 1

为什么只删除作业中的文件？我认为在工作中添加删除代码会更好。或者，您可以在作业完成时向作业添加一个标志，并在 main 方法中添加等待代码(例如 while true)以等待标志为 true，然后执行删除。