Add Table of Contents (TOC) to PDF in Java

Adding table of contents (TOC) to our document is a useful way to show readers what chapters are included in our document. When readers click on the table of contents, they can quickly navigate to the specific parts that they’re interested.

In this blog, I will introduce how to add table of contents (TOC) to a PDF document programmatically in Java using Free Spire.PDF for Java library.

import com.spire.pdf.*;
import com.spire.pdf.actions.PdfGoToAction;
import com.spire.pdf.annotations.*;
import com.spire.pdf.general.PdfDestination;
import com.spire.pdf.graphics.*;
import java.awt.*;
import java.awt.geom.*;

public class TableOfContent {
    public static void main(String[] args) throws Exception
    {
        //load PDF document
        PdfDocument doc = new PdfDocument("sample.pdf");
        int pageCount = doc.getPages().getCount();
        //Insert a page as the first page to draw TOC
        PdfPageBase tocPage = doc.getPages().insert(0);
        //set TOC title
        String title = "Table Of Contents";
        PdfTrueTypeFont titleFont = new PdfTrueTypeFont(new Font("Arial",  Font.BOLD,20));
        PdfStringFormat centerAlignment = new PdfStringFormat(PdfTextAlignment.Center, PdfVerticalAlignment.Middle);
        Point2D location = new Point2D.Float((float) tocPage.getCanvas().getClientSize().getWidth() / 2, (float) titleFont.measureString(title).getHeight());
        tocPage.getCanvas().drawString(title, titleFont, PdfBrushes.getCornflowerBlue(), location, centerAlignment);
        //draw TOC content and set font, style and location
        PdfTrueTypeFont titlesFont = new PdfTrueTypeFont(new Font("Arial", Font.PLAIN,14));
        String[] titles = new String[pageCount];
        for (int i = 0; i < titles.length; i++) {
            titles[i] = String.format("page%1$s", i + 1);
        }
        float y = (float)titleFont.measureString(title).getHeight() + 10;
        float x = 0;
        for (int i = 1; i <= pageCount; i++) {
            String text = titles[i - 1];
            Dimension2D titleSize = titlesFont.measureString(text);
            PdfPageBase navigatedPage = doc.getPages().get(i);
            String pageNumText = (String.valueOf(i+1));
            Dimension2D pageNumTextSize = titlesFont.measureString(pageNumText);
            tocPage.getCanvas().drawString(text, titlesFont, PdfBrushes.getCadetBlue(), 0, y);
            float dotLocation = (float)titleSize.getWidth() + 2 + x;
            float pageNumlocation = (float)(tocPage.getCanvas().getClientSize().getWidth() - pageNumTextSize.getWidth());
            for (float j = dotLocation; j < pageNumlocation; j++) {
                if (dotLocation >= pageNumlocation) {
                    break;
                }
                tocPage.getCanvas().drawString(".", titlesFont, PdfBrushes.getGray(), dotLocation, y);
                dotLocation += 3;
            }
            tocPage.getCanvas().drawString(pageNumText, titlesFont, PdfBrushes.getCadetBlue(), pageNumlocation, y);
            //add action to TOC in order to link it to corresponding location in the file
            Rectangle2D titleBounds = new Rectangle2D.Float(0,y,(float)tocPage.getCanvas().getClientSize().getWidth(),(float)titleSize.getHeight());
            PdfDestination Dest = new PdfDestination(navigatedPage, new Point2D.Float(-doc.getPageSettings().getMargins().getTop(), -doc.getPageSettings().getMargins().getLeft()));
            PdfActionAnnotation action = new PdfActionAnnotation(titleBounds, new PdfGoToAction(Dest));
            action.setBorder(new PdfAnnotationBorder(0));
            ((PdfNewPage) ((tocPage instanceof PdfNewPage) ? tocPage : null)).getAnnotations().add(action);
            y += titleSize.getHeight() + 10;
        }

        //save the resultant document
        doc.saveToFile("addTableOfContent.pdf");
        doc.close();
    }
}

Output: