In case you use a current iText version (i.e. 5.4.x as of now) have a look at the sample MovieHistory2 from iText in Action — 2nd Edition which shows how to add headers (different ones for odd and even pages) to a PDF while creating it.
Most essential is a PdfPageEventHelper
implementation
/** Inner class to add a header and a footer. */
class HeaderFooter extends PdfPageEventHelper {
/** Alternating phrase for the header. */
Phrase[] header = new Phrase[2];
/** Current page number (will be reset for every chapter). */
int pagenumber;
/**
* Initialize one of the headers.
* @see com.itextpdf.text.pdf.PdfPageEventHelper#onOpenDocument(
* com.itextpdf.text.pdf.PdfWriter, com.itextpdf.text.Document)
*/
public void onOpenDocument(PdfWriter writer, Document document) {
header[0] = new Phrase("Movie history");
}
/**
* Initialize one of the headers, based on the chapter title;
* reset the page number.
* @see com.itextpdf.text.pdf.PdfPageEventHelper#onChapter(
* com.itextpdf.text.pdf.PdfWriter, com.itextpdf.text.Document, float,
* com.itextpdf.text.Paragraph)
*/
public void onChapter(PdfWriter writer, Document document,
float paragraphPosition, Paragraph title) {
header[1] = new Phrase(title.getContent());
pagenumber = 1;
}
/**
* Increase the page number.
* @see com.itextpdf.text.pdf.PdfPageEventHelper#onStartPage(
* com.itextpdf.text.pdf.PdfWriter, com.itextpdf.text.Document)
*/
public void onStartPage(PdfWriter writer, Document document) {
pagenumber++;
}
/**
* Adds the header and the footer.
* @see com.itextpdf.text.pdf.PdfPageEventHelper#onEndPage(
* com.itextpdf.text.pdf.PdfWriter, com.itextpdf.text.Document)
*/
public void onEndPage(PdfWriter writer, Document document) {
Rectangle rect = writer.getBoxSize("art");
switch(writer.getPageNumber() % 2) {
case 0:
ColumnText.showTextAligned(writer.getDirectContent(),
Element.ALIGN_RIGHT, header[0],
rect.getRight(), rect.getTop(), 0);
break;
case 1:
ColumnText.showTextAligned(writer.getDirectContent(),
Element.ALIGN_LEFT, header[1],
rect.getLeft(), rect.getTop(), 0);
break;
}
ColumnText.showTextAligned(writer.getDirectContent(),
Element.ALIGN_CENTER, new Phrase(String.format("page %d", pagenumber)),
(rect.getLeft() + rect.getRight()) / 2, rect.getBottom() - 18, 0);
}
}
which is registered like this:
PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream(RESULT));
HeaderFooter event = new HeaderFooter();
writer.setBoxSize("art", new Rectangle(36, 54, 559, 788));
writer.setPageEvent(event);
EDIT: As requested in the comments, a simpler variant of the onEndPage
method with a static header instead of the alternating one:
public void onEndPage(PdfWriter writer, Document document)
{
Rectangle rect = writer.getBoxSize("art");
ColumnText.showTextAligned(writer.getDirectContent(),
Element.ALIGN_RIGHT, new Phrase("My static header text"),
rect.getRight(), rect.getTop(), 0);
ColumnText.showTextAligned(writer.getDirectContent(),
Element.ALIGN_CENTER, new Phrase(String.format("page %d", pagenumber)),
(rect.getLeft() + rect.getRight()) / 2, rect.getBottom() - 18, 0);
}