我使用iText通过使用PDFCopy合并大量PDF来创建单个PDF.我需要在本文档的开头创建一个TOC(而不是书签),其中包含指向每个源PDF的第一页的可点击链接.

合并pdf的代码

Document PDFJoinInJava = new Document();
PdfCopy PDFCombiner = new PdfCopy(PDFJoinInJava, outputStream);
PdfCopy.PageStamp stamp;
PDFJoinInJava.open();
PdfReader ReadInputPDF;

List<InputStream> pdfs = streamOfPDFFiles;
List<PdfReader> readers = new ArrayList<PdfReader>();
int totalPages = 0;
Iterator<InputStream> iteratorPDFs = pdfs.iterator();
for (; iteratorPDFs.hasNext(); pdfCounter++) {
    InputStream pdf = iteratorPDFs.next();
    PdfReader pdfReader = new PdfReader(pdf);
    readers.add(pdfReader);
    totalPages += pdfReader.getNumberOfPages();
    pdf.close();
}
int number_of_pages;
int currentPageNumber = 0;
int pageOfCurrentReaderPDF = 0;
Iterator<PdfReader> iteratorPDFReader = readers.iterator();

PdfImportedPage page;
// Loop through the PDF files and add to the output.
int count = 1;

while (iteratorPDFReader.hasNext()) {
    PdfReader pdfReader = iteratorPDFReader.next();
    count++;
    number_of_pages = pdfReader.getNumberOfPages();

    // Create a new page in the target for each source page.
    for (int pageNum = 0; pageNum < number_of_pages;) {
        currentPageNumber++;
        pageOfCurrentReaderPDF++;
        page = PDFCombiner.getImportedPage(pdfReader, ++pageNum);
        ColumnText.showTextAligned(stamp.getUnderContent(),
                        Element.ALIGN_RIGHT, new Phrase(String
                                .format("%d", currentPageNumber),new Font(FontFamily.TIMES_ROMAN,3)),
                        50, 50, 0);
            stamp.alterContents();

        PDFCombiner.addPage(page);
    }
}
PDFJoinInJava.close();

解决方法:

你要求的东西应该是微不足道的,但事实并非如此.请看一下MergeWithToc的例子.您将看到合并PDF的代码是正确的,但在我的示例中,我添加了一个额外的功能：

chunk = new Chunk(String.format("Page %d", pageNo));
if (i == 1)
    chunk.setLocalDestination("p" + pageNo);
ColumnText.showTextAligned(stamp.getUnderContent(),
    Element.ALIGN_RIGHT, new Phrase(chunk), 559, 810, 0);

对于每个第一页,我将命名目标定义为本地目标.我们使用p后跟页码作为名称.

我们将在一个将用作TOC的额外页面中使用这些命名目标：

PdfReader reader = new PdfReader(SRC3);
page = copy.getImportedPage(reader, 1);
stamp = copy.createPageStamp(page);
Paragraph p;
PdfAction action;
PdfAnnotation link;
float y = 770;
ColumnText ct = new ColumnText(stamp.getOverContent());
ct.setSimpleColumn(36, 36, 559, y);
for (Map.Entry<Integer, String> entry : toc.entrySet()) {
    p = new Paragraph(entry.getValue());
    p.add(new Chunk(new DottedLineSeparator()));
    p.add(String.valueOf(entry.getKey()));
    ct.addElement(p);
    ct.go();
    action = PdfAction.gotoLocalPage("p" + entry.getKey(), false);
    link = new PdfAnnotation(copy, 36, ct.getYLine(), 559, y, action);
    stamp.addAnnotation(link);
    y = ct.getYLine();
}
ct.go();
stamp.alterContents();
copy.addPage(page);

在我的例子中,我假设TOC适合单个页面.您必须跟踪y值并在其值低于下边距时创建新页面.

如果您希望TOC成为第一页,则需要在第二页重新排序页面.这在MergeWithToc2示例中显示：

reader = new PdfReader(baos.toByteArray());
n = reader.getNumberOfPages();
reader.selectPages(String.format("%d, 1-%d", n, n-1));
PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(filename));
stamper.close();