如何使用pdf框中的书签选择pdf页面？

Question

抱歉，我是PDF框的新手，正在寻找一种解决方案，该方案如何使用书签名称获取特定的pdf页面？像下面的代码片段一样，我试图循环所有页面，但卡住了将书签与我需要的页面链接。有人可以帮忙吗？

import java.awt.print.PrinterException;
import java.io.File;
import java.io.IOException;
import org.apache.pdfbox.cos.COSObject;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.encryption.InvalidPasswordException;
import org.apache.pdfbox.pdmodel.interactive.documentnavigation.destination.PDPageFitWidthDestination;
import org.apache.pdfbox.pdmodel.interactive.documentnavigation.outline.PDDocumentOutline;
import org.apache.pdfbox.pdmodel.interactive.documentnavigation.outline.PDOutlineItem;
import org.apache.pdfbox.pdmodel.interactive.documentnavigation.outline.PDOutlineNode;

public class PDFLoader {

    public static void main(String[] args) throws InvalidPasswordException, IOException, PrinterException {


          File file = new File("d:\\pdf\\sample.pdf"); 
          PDDocument document = PDDocument.load(file); 
          PDPage page01 = document.getDocumentCatalog().getPages().get(0);
          PDPage page02 = document.getDocumentCatalog().getPages().get(1);

          PDDocumentOutline outline =  document.getDocumentCatalog().getDocumentOutline();
          printBookmark(outline, "");
          PDDocument doc = new PDDocument();
          doc.addPage(page01);
          doc.addPage(page02);
          doc.save("d:\\pdf\\newSample.pdf");
          doc.close();

    }



public static PDPage getBookmark(PDOutlineNode bookmark, String indentation) throws IOException
    {
        PDOutlineItem current = bookmark.getFirstChild();
        while (current != null)

        {
            System.out.println(indentation + current.getTitle());



            if (current.getAction() instanceof PDActionGoTo)
            {
                PDActionGoTo gta = (PDActionGoTo) current.getAction();
                if (gta.getDestination() instanceof PDPageDestination)
                {

                    if(current.getTitle().equals("MyBookMark")){


                        PDPageDestination pd = (PDPageDestination) current.getDestination();
                        System.out.println("Destination page: " + pd.retrievePageNumber());
                        return pd.getPage();

                        }
                }
            }

            getBookmark(current, indentation + "    ");
            current = current.getNextSibling();

            }


        return null;
    }







//Stack Trace
    Exception in thread "main" java.lang.NullPointerException
    at com.mypackage.PDFLoader.getBookmark(PDFLoader.java:67)
    at com.mypackage.PDFLoader.main(PDFLoader.java:40)

Answer 1

事实证明，在PDF中，页面目标不在书签的目标条目中，而是在书签的操作项中（是的，PDF使您可以通过两种方式来执行同一操作）。将此添加到您的代码：

if (current.getDestination() instanceof PDPageDestination)
{
    PDPageDestination pd = (PDPageDestination) current.getDestination();
    System.out.println("Destination page: " + (pd.retrievePageNumber() + 1));
    return pd.getPage();
}
if (current.getAction() instanceof PDActionGoTo)
{
    PDActionGoTo gta = (PDActionGoTo) current.getAction();
    if (gta.getDestination() instanceof PDPageDestination)
    {
        PDPageDestination pd = (PDPageDestination) gta.getDestination();
        System.out.println("Destination page: " + (pd.retrievePageNumber() + 1));
        return pd.getPage();
    }
}