如何用iText7获取PDF的书签页码

import com.itextpdf.kernel.pdf.PdfDocument;
import com.itextpdf.kernel.pdf.PdfOutline;
import com.itextpdf.kernel.pdf.PdfReader;
import com.itextpdf.kernel.pdf.navigation.PdfDestination;

public class PDFBookmarkPageNumber {
    public static void main(String[] args) {
        String filePath = "path/to/your/pdf/file.pdf";

        try {
            PdfReader reader = new PdfReader(filePath);
            PdfDocument document = new PdfDocument(reader);

            PdfOutline rootOutline = document.getOutlines(false);
            printBookmarkPageNumbers(rootOutline, "");

            document.close();
            reader.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static void printBookmarkPageNumbers(PdfOutline outline, String indent) {
        System.out.println(indent + "Title: " + outline.getTitle());
        System.out.println(indent + "Page Number: " + getPageNumber(outline.getDestination()));

        PdfOutline child = outline.getFirstChild();
        while (child != null) {
            printBookmarkPageNumbers(child, indent + "  ");
            child = child.getNext();
        }
    }

    public static int getPageNumber(PdfDestination destination) {
        return destination != null ? destination.retrievePageNumber() + 1 : -1;
    }
}