不打印由ByteArrayOutputStream创建的iText pdf文件

Question

我编码用ByteArrayOutputStream在内存中创建iText PDF文件，点击一个按钮，同时点击同一个按钮打印该PDF文件。编码没有错误..

以下是特定按钮的代码;

int print = JOptionPane.showConfirmDialog(null, "Do you really want to Print the Invoice ?","Print Confirmation",JOptionPane.YES_NO_OPTION);
    if((print)==0){
       try{

        String saledate = ((JTextField)dayChooser.getDateEditor().getUiComponent()).getText();
        String invoice = InvoiceNo_txt.getText();
        String citems = countitems_txt.getText();
        String tDis =totalDiscount_txt.getText();
        String ntotal = NetTotal_txt.getText();

        //setting data to saleinfo db table
        try{
            String sql = "Insert into saleinfo (SaleDate,InvoiceNo,TotalItems,TotalDiscount,NetTotal)values (?,?,?,?,?)";

            pst=conn.prepareStatement(sql);


            pst.setString(1, saledate);
            pst.setString(2, invoice);
            pst.setString(3, citems);
            pst.setString(4, tDis);
            pst.setString(5, ntotal);

            pst.execute();

        }catch(Exception e){

        }


        //creting itext report for prining


        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        Document salepdf = new Document();
        PdfWriter.getInstance(salepdf,baos);
        //salepdf.setPageSize(PageSize.A7);



        salepdf.open();
       //file content added here
        salepdf.close();


        byte[] pdfbyte = baos.toByteArray();

        ByteArrayInputStream bis = new ByteArrayInputStream(pdfbyte);
        DocFlavor flavor = DocFlavor.INPUT_STREAM.AUTOSENSE;
        AttributeSet attributeSet = new HashAttributeSet();
        attributeSet.add(new PrinterName("NPI8DA48A", null));
        PrintService service = PrintServiceLookup.lookupDefaultPrintService();

        DocPrintJob job= service.createPrintJob();
        Doc pdfp = new SimpleDoc(bis, flavor, null);
        PrintJobWatcher watcher = new PrintJobWatcher(job);
        job.print(pdfp, null); 
        watcher.waitForDone(); 



    }catch(DocumentException | PrintException ex){
        Logger.getLogger(Newsale.class.getName()).log(Level.SEVERE, null, ex);

    }
    //set null  feilds after printing
    DefaultTableModel model = (DefaultTableModel) tableSale.getModel();
    model.setRowCount(0);
    countitems_txt.setText("");
    totalDiscount_txt.setText("");
    NetTotal_txt.setText("");
    }

PrintJobWatcher类;

static class PrintJobWatcher {
    // true iff it is safe to close the print job's input stream
    boolean done = false;

    PrintJobWatcher(DocPrintJob job) {
        // Add a listener to the print 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;
                    PrintJobWatcher.this.notify();
                }
            }
        });
    }
    public synchronized void waitForDone() {
        try {
            while (!done) {
                wait();
            }
        } catch (InterruptedException e) {
        }
    }
}

请注意这一点;
问题是，当我单击“打印”按钮时，文件将被添加到打印队列中并立即消失..

为什么代码不起作用？