在 JAVA 中将 PDF 打印为字节数组

Question

我需要为我的打印机打印一个 pdf 文件。使用此代码，我已将我的 pdf 转换为 bytearray，但我被卡住了，不知道如何将其发送到打印机。有人可以帮助我吗？

    File file = new File("java.pdf");

    FileInputStream fis = new FileInputStream(file);
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    byte[] buf = new byte[1024];

    try {
        for (int readNum; (readNum = fis.read(buf)) != -1;) {
            bos.write(buf, 0, readNum); //no doubt here is 0
            //Writes len bytes from the specified byte array starting at offset off to this byte array output stream.
            System.out.println("read " + readNum + " bytes,");
        }
    } catch (IOException ex) {
        System.out.println("ERROR!");
    }
    byte[] bytes = bos.toByteArray();

提前谢谢你。

Answer 1

要遵循的步骤：

1. 在您的环境中查找默认打印机服务。
2. 为 PDF 定义用于打印的文档风格。
3. 准备要从字节数组打印的文档。
4. 执行打印作业。

示例代码sn-p：

byte[] bytes = bos.toByteArray();
ByteArrayInputStream bais = new ByteArrayInputStream( bytes );

// First identify the default print service on the system  
PrintService printService = PrintServiceLookup.lookupDefaultPrintService();  

// prepare the flvaor you are intended to print  
DocFlavor docFlavor = DocFlavor.BYTE_ARRAY.PDF;  

// prepare the print job
DocPrintJob printJob = printService.createPrintJob();  

// prepare the document, with default attributes, ready to print  
Doc docToPrint = new SimpleDoc( bais, docFlavor, null );  

// now send the doc to print job, with no attributes to print
printJob.print( docToPrint, null );

Answer 2

使用ByteArrayInputStream 会抛出java.lang.IllegalArgumentException，但常规字节数组对我有用。修改Ravinder Reddy的例子：

    // Get default print service
    PrintService printService = PrintServiceLookup.lookupDefaultPrintService();

    // Create a print job
    DocPrintJob printJob = printService.createPrintJob();

    // Optional fancy listener
    printJob.addPrintJobListener(new PrintJobAdapter() {
        @Override
        public void printJobCompleted(PrintJobEvent pje) {
            System.out.println("PDF printing completed");
            super.printJobCompleted(pje);
        }

        @Override
        public void printJobFailed(PrintJobEvent pje) {
            System.out.println("PDF printing failed");
            super.printJobFailed(pje);
        }
    });

    // Check the PDF file and get a byte array
    File pdfFile = new File("path/to/pdf");
    if (pdfFile.exists() && pdfFile.isFile()) {
        byte[] PDFByteArray = Files.readAllBytes(FileSystems.getDefault().getPath(pdfFile.getAbsolutePath()));

        // Create a doc and print it
        Doc doc = new SimpleDoc(PDFByteArray, DocFlavor.BYTE_ARRAY.AUTOSENSE, null);
        printJob.print(doc, null);
    }

Answer 3

另一种方法是使用intent 发送pdf 文件，这里是example

示例代码：

Intent prnIntent = new Intent(Intent.ACTION_SEND);
prnIntent.putExtra(Intent.EXTRA_STREAM, uri);

prnIntent.setType("application/pdf");


startActivity(Intent.createChooser(prnIntent , "Send pdf using:"));

使用这种方法无需使用缓冲区，而是将 pdf 文件直接发送到打印机！