Java add multiple headers to PDF

import com.spire.pdf.*;
import com.spire.pdf.graphics.*;
import java.awt.*;
import java.awt.geom.*;

public class addDifferentHeaders {
    public static void main(String[] args) {
        String output = "output/addDifferentHeaders.pdf";

        //load the sample PDF document
        PdfDocument doc = new PdfDocument();
        doc.loadFromFile("Sample.pdf");
        String header1 = "Add header by Spire.PDF";
        String header2 = "Different header";

        //define style
        PdfTrueTypeFont font = new PdfTrueTypeFont(new Font("Arial",  Font.BOLD,12));
        PdfBrush brush= PdfBrushes.getBlue();
        Rectangle2D rect = new Rectangle2D.Float();
        Dimension2D dimension2D = new Dimension();
        dimension2D.setSize(doc.getPageSettings().getSize().getWidth(),50f);
        rect.setFrame(new Point2D.Float(0, 20), dimension2D);
        PdfStringFormat format=new PdfStringFormat();
        format.setAlignment(PdfTextAlignment.Center);
        //draw header string for the first page
        doc.getPages().get(0).getCanvas().drawString(header1,font,brush,rect,format);

        //draw header string for the second page
        format.setAlignment( PdfTextAlignment.Left);
        doc.getPages().get(1).getCanvas().drawString(header2, font, brush, rect, format);

        //save the document
        doc.saveToFile(output, FileFormat.PDF);
    }
}