String inputFileName = "AddPageStamp.pdf";
String pageStampFileName = "PageStamp.pdf";
String outputFileName = "AddPageStamp_out.pdf";
Document pdfDocument = new Document(DATA_DIR.resolve(inputFileName).toString());
PdfPageStamp bluePageStamp = new PdfPageStamp(DATA_DIR.resolve(pageStampFileName).toString(), 1);
bluePageStamp.setHeight(800);
bluePageStamp.setBackground(true);
PdfPageStamp plumPageStamp = new PdfPageStamp(DATA_DIR.resolve(pageStampFileName).toString(), 2);
plumPageStamp.setHeight(800);
plumPageStamp.setBackground(true);
for (int i = 1; i < 5; i++) {
if (i % 2 == 0)
pdfDocument.getPages().get_Item(i).addStamp(bluePageStamp);
else
pdfDocument.getPages().get_Item(i).addStamp(plumPageStamp);
}
pdfDocument.save(DATA_DIR.resolve(outputFileName).toString());
pdfDocument.close();