I'm using the following code to merge PDFs together using iText:
public static void concatenatePdfs(List<File> listOfPdfFiles, File outputFile) throws DocumentException, IOException {
Document document = new Document();
FileOutputStream outputStream = new FileOutputStream(outputFile);
PdfWriter writer = PdfWriter.getInstance(document, outputStream);
document.open();
PdfContentByte cb = writer.getDirectContent();
for (File inFile : listOfPdfFiles) {
PdfReader reader = new PdfReader(inFile.getAbsolutePath());
for (int i = 1; i <= reader.getNumberOfPages(); i++) {
document.newPage();
PdfImportedPage page = writer.getImportedPage(reader, i);
cb.addTemplate(page, 0, 0);
}
}
outputStream.flush();
document.close();
outputStream.close();
}
This usually works great! But once and a while, it's rotating some of the pages by 90 degrees? Anyone ever have this happen?
I am looking into the PDFs themselves to see what is special about the ones that are being flipped.
There are errors once in a while because you are using the wrong method to concatenate documents. Please read chapter 6 of my book and you'll notice that using PdfWriter
to concatenate (or merge) PDF documents is wrong:
Concatenating PDFs is done using PdfCopy
, see for instance the FillFlattenMerge2 example:
Document document = new Document();
PdfCopy copy = new PdfSmartCopy(document, new FileOutputStream(dest));
document.open();
PdfReader reader;
String line = br.readLine();
// loop over readers
// add the PDF to PdfCopy
reader = new PdfReader(baos.toByteArray());
copy.addDocument(reader);
reader.close();
// end loop
document.close();
There are other examples in the book .
In case anyone is looking for it, using Bruno Lowagie's correct answer above, here is the version of the function that does not seem to have the page flipping issue i described above:
public static void concatenatePdfs(List<File> listOfPdfFiles, File outputFile) throws DocumentException, IOException {
Document document = new Document();
FileOutputStream outputStream = new FileOutputStream(outputFile);
PdfCopy copy = new PdfSmartCopy(document, outputStream);
document.open();
for (File inFile : listOfPdfFiles) {
PdfReader reader = new PdfReader(inFile.getAbsolutePath());
copy.addDocument(reader);
reader.close();
}
document.close();
}
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