如何在pdf框中使用书签选择pdf页面?

Question

>抱歉，我是PDF框的新手，正在寻找有关如何使用书签名称获取特定pdf页面的解决方案？就像下面的代码片段一样，我试图循环所有页面，但坚持将书签与我需要的页面链接。任何人都可以帮忙吗？

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，在您的PDF中，页面目标不在书签的目标条目中，而是在书签的操作条目中(是的，PDF使有两种方法可以做同样的事情(。将此添加到您的代码中：

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();
}
}