iText 7 Html到Pdf转换并将外部文件链接到生成的Pdf

Question

我在合并从iText生成的两个PDF时遇到了一个问题。我是iText7的新手，我正在从html创建一个pdf，并用excel（.xls）创建另一个pdf作为pdf的嵌入文档。我想合并这2个文件。

    ByteArrayOutputStream htmlToPdfContent = new ByteArrayOutputStream();
    PdfWriter writer = new PdfWriter(htmlToPdfContent);
    PdfDocument pdf = new PdfDocument(writer);
    pdf.setTagged();
    PageSize pageSize = PageSize.A4.rotate();
    pdf.setDefaultPageSize(pageSize);
    ConverterProperties properties = new ConverterProperties();
    HtmlConverter.convertToPdf(htmlContent, pdf, properties);

    FileUtils.cleanDirectory(new File(outputDir));

    ByteArrayOutputStream pdfResult = new ByteArrayOutputStream();
    PdfWriter writerResult = new PdfWriter(pdfResult);
    PdfDocument pdfDocResult = new PdfDocument(writerResult);

    PdfReader reader = new PdfReader(new ByteArrayInputStream(htmlToPdfContent.toByteArray()));
    PdfDocument pdfDoc = new PdfDocument(reader);
    pdfDoc.copyPagesTo(1, pdfDoc.getNumberOfPages(), pdfDocResult);

    ByteArrayOutputStream pdfAttach = new ByteArrayOutputStream();
    PdfDocument pdfLaunch = new PdfDocument(new PdfWriter(pdfAttach));
    Rectangle rect = new Rectangle(36, 700, 100, 100);
    byte[] embeddedFileContentBytes = Files.readAllBytes(Paths.get(excelPath));
    PdfFileSpec fs = PdfFileSpec.createEmbeddedFileSpec(pdfLaunch, embeddedFileContentBytes, null, "test.xlsx", null, null);
    PdfAnnotation attachment = new PdfFileAttachmentAnnotation(rect, fs)
            .setContents("Click me");
    pdfLaunch.addNewPage().addAnnotation(attachment);

    PdfDocument appliedChanges = new PdfDocument(new PdfReader(new ByteArrayInputStream(pdfAttach.toByteArray())));

    appliedChanges.copyPagesTo(1, appliedChanges.getNumberOfPages(), pdfDocResult);
    try(OutputStream outputStream = new FileOutputStream(dest)) {
        pdfResult.writeTo(outputStream);
    }

13:56:05.724 [main] ERROR com.itextpdf.kernel.pdf.PdfReader - Error occurred while reading cross reference table. Cross reference table will be rebuilt.
com.itextpdf.io.IOException: Error at file pointer 19,272.
    at com.itextpdf.io.source.PdfTokenizer.throwError(PdfTokenizer.java:678)
    at com.itextpdf.kernel.pdf.PdfReader.readXrefSection(PdfReader.java:801)
    at com.itextpdf.kernel.pdf.PdfReader.readXref(PdfReader.java:774)
    at com.itextpdf.kernel.pdf.PdfReader.readPdf(PdfReader.java:538)
    at com.itextpdf.kernel.pdf.PdfDocument.open(PdfDocument.java:1818)
    at com.itextpdf.kernel.pdf.PdfDocument.<init>(PdfDocument.java:238)
    at com.itextpdf.kernel.pdf.PdfDocument.<init>(PdfDocument.java:221)
    at com.mediaocean.prisma.order.command.infrastructure.pdf.itext.PdfAttachmentLaunch.main(PdfAttachmentLaunch.java:76)
Caused by: com.itextpdf.io.IOException: xref subsection not found.
    ... 8 common frames omitted
Exception in thread "main" com.itextpdf.kernel.PdfException: Trailer not found.
    at com.itextpdf.kernel.pdf.PdfReader.rebuildXref(PdfReader.java:1064)
    at com.itextpdf.kernel.pdf.PdfReader.readPdf(PdfReader.java:543)
    at com.itextpdf.kernel.pdf.PdfDocument.open(PdfDocument.java:1818)
    at com.itextpdf.kernel.pdf.PdfDocument.<init>(PdfDocument.java:238)
    at com.itextpdf.kernel.pdf.PdfDocument.<init>(PdfDocument.java:221)
    at com.mediaocean.prisma.order.command.infrastructure.pdf.itext.PdfAttachmentLaunch.main(PdfAttachmentLaunch.java:88)
13:56:05.773 [main] ERROR com.itextpdf.kernel.pdf.PdfReader - Error occurred while reading cross reference table. Cross reference table will be rebuilt.
com.itextpdf.io.IOException: PDF startxref not found.
    at com.itextpdf.io.source.PdfTokenizer.getStartxref(PdfTokenizer.java:262)
    at com.itextpdf.kernel.pdf.PdfReader.readXref(PdfReader.java:753)
    at com.itextpdf.kernel.pdf.PdfReader.readPdf(PdfReader.java:538)
    at com.itextpdf.kernel.pdf.PdfDocument.open(PdfDocument.java:1818)
    at com.itextpdf.kernel.pdf.PdfDocument.<init>(PdfDocument.java:238)
    at com.itextpdf.kernel.pdf.PdfDocument.<init>(PdfDocument.java:221)
    at com.mediaocean.prisma.order.command.infrastructure.pdf.itext.PdfAttachmentLaunch.main(PdfAttachmentLaunch.java:88)

请指教。提前感谢！！

Answer 1

您对代码的更改与我对问题第一次修订版的回答中所建议的不同，您现在转换为以前未使用的PDFDocument PDF，而不是直接转换为ByteArrayOutputStream HtmlTopDfContent。

这实际上也是解决问题的一个可能的答案。因此，这里不再出现异常：

PdfReader reader = new PdfReader(new ByteArrayInputStream(htmlToPdfContent.toByteArray()));
PdfDocument pdfDoc = new PdfDocument(reader);

相反，您现在得到了一个更深入的异常，如下所示：

PdfDocument appliedChanges = new PdfDocument(new PdfReader(new ByteArrayInputStream(pdfAttach.toByteArray())));

ByteArrayOutputStream pdfAttach = new ByteArrayOutputStream();
PdfDocument pdfLaunch = new PdfDocument(new PdfWriter(pdfAttach));
[...]
pdfLaunch.addNewPage().addAnnotation(attachment);
pdfLaunch.close(); //<==== added

PdfDocument appliedChanges = new PdfDocument(new PdfReader(new ByteArrayInputStream(pdfAttach.toByteArray())));

appliedChanges.copyPagesTo(1, appliedChanges.getNumberOfPages(), pdfDocResult);
pdfDocResult.close(); //<==== added
try(OutputStream outputStream = new FileOutputStream(dest)) {
    pdfResult.writeTo(outputStream);
}

ByteArrayOutputStream htmlToPdfContent = new ByteArrayOutputStream();
PdfWriter writer = new PdfWriter(htmlToPdfContent);
PdfDocument pdf = new PdfDocument(writer);
pdf.setTagged();
PageSize pageSize = PageSize.A4.rotate();
pdf.setDefaultPageSize(pageSize);
ConverterProperties properties = new ConverterProperties();
HtmlConverter.convertToPdf(content, htmlToPdfContent, properties);

这使得htmltopdfcontent的内容成为两者输出的大杂烩，特别是不是有效的PDF。

由于不向PDF添加任何内容，因此可以安全地删除这些内容，并将上面的摘录减少到

ByteArrayOutputStream htmlToPdfContent = new ByteArrayOutputStream();
ConverterProperties properties = new ConverterProperties();
HtmlConverter.convertToPdf(content, htmlToPdfContent, properties);