为什么pdf下载的bij Trinidad fileDownloadActionListener无法用pdf打开reader？

Question

我确实从 String 创建了 PDF，这个 String 在 xml format 中，并以 trinidad 按钮的形式呈现给用户 fileDownloadActionListener.

我可以下载PDF但是不能先用PDF reader比如adobe reader打开它我认为它可能已损坏，但事实并非如此，因为我可以使用 Visual Studio Code 或任何其他文本编辑器打开它，例如 notepad.

1- 为什么我不能用 adobe 打开它 reader?

2- 为什么要这样做有更好的办法吗？

前端：

<h:commandButton id="mehrpdf" value="Download PDF" styleClass="popupButton">
        <tr:fileDownloadActionListener filename="mehr.pdf"  contentType="application/pdf; charset=utf-8" method="#{bean.downloadMehr}" />
</h:commandButton>

后端：

public void downloadMehr(FacesContext context, OutputStream out) throws IOException
    {
        String fetchedXmlMessage = getFetchedXmlMessage();
        XmlPrettifier prettifier = XmlPrettifierFactory.getInstance();
        prettyXmlMessage = prettifier.makePretty(fetchedXmlMessage);

        // alternativ way
        File pdfFile = createPdfFromTxt(prettyXmlMessage);

        OutputStreamWriter w = new OutputStreamWriter(out, "UTF-8");
        w.write(prettyXmlMessage);
        w.flush();
    }

pdf创建：

public File createPdfFromTxt(String content) throws IOException, DocumentException {

        //define the size of the PDF file, version and output file
        File outfile = File.createTempFile("mehr", ".pdf");
        Document pdfDoc = new Document(PageSize.A4);
        PdfWriter.getInstance(pdfDoc, new FileOutputStream(outfile)).setPdfVersion(PdfWriter.PDF_VERSION_1_7);
        pdfDoc.open();

        //define the font and also the command that is used to generate new paragraph
        Font myfont = new Font();
        myfont.setStyle(Font.NORMAL);
        myfont.setSize(11);
        pdfDoc.add(new Paragraph("\n"));

        // add paragraphs into newly created PDF file
        File contentFile = File.createTempFile("content", ".txt");
        FileUtils.writeStringToFile(contentFile, content);

        BufferedReader br = new BufferedReader(new FileReader(contentFile));
        String strLine;
        while ((strLine = br.readLine()) != null) {
            Paragraph para = new Paragraph(strLine + "\n", myfont);
            para.setAlignment(Element.ALIGN_JUSTIFIED);
            pdfDoc.add(para);
        }
        pdfDoc.close();
        br.close();

        return outfile;
    }

Answer 1

我确实根据上面命令中提到的人更改了后端，现在我可以用PDF阅读它reader。谢谢大家。

public void downloadMehr(FacesContext context, OutputStream out) throws IOException
    {
        String fetchedXmlMessage = getFetchedXmlMessage();
        XmlPrettifier prettifier = XmlPrettifierFactory.getInstance();
        prettyXmlMessage = prettifier.makePretty(fetchedXmlMessage);

        // create pdf from string
        PdfCreator pdfCreator = new PdfCreator( prettyXmlMessage);
        File pdfFile = pdfCreator.create();

        FileInputStream inStream = new FileInputStream(pdfFile);
        byte[] buffer = new byte[4096];
        int bytesRead = -1;

        while ((bytesRead = inStream.read(buffer)) != -1) {
            outputStream.write(buffer, 0, bytesRead);
        }

        inStream.close();
        outputStream.close();
    }

为什么pdf下载的bij Trinidad fileDownloadActionListener无法用pdf打开reader？

Why pdf downloaded bij Trinidad fileDownloadActionListener can't be open with pdf reader?

pdf

jsf

trinidad

itext