How do I merge two PDF files with attachments using itext? - itext

Question

I am trying to merge two pdf files (file1.pdf and file2.pdf) into a single file file3.pdf. One of the source files, file2.pdf has few attachments.
Using PdfCopyFields addDocument method does not include the attachments in the source pdf files to the destination pdf file. How do I achieve this?
Extracting the document level attachments from source files using PdfDictionary and adding them to the destination file using PdfWriter addFileAttachment method works.
Can you please let me know if there is any other efficient method to include the attachments from source pdf files to be included in destination pdf file after merging?
This is the sample code that I am using to replicate the scenario.
public class TestItext
{
public String[] attachments;
public TestItext()
{
attachments = new String[2];
}
public static void main(String[] args)
{
try
{
TestItext obj = new TestItext();
obj.extractDocLevelAttachments("C:\\source.pdf");
obj.addAttachments("C:\\source.pdf","C:\\temp\\dest.pdf");
}
catch(Exception e)
{
e.printStackTrace();
}
}
public void extractDocLevelAttachments(String filename) throws IOException
{
PdfReader reader = new PdfReader(filename);
PdfDictionary root = reader.getCatalog();
PdfDictionary documentnames = root.getAsDict(PdfName.NAMES);
PdfDictionary embeddedfiles = documentnames.getAsDict(PdfName.EMBEDDEDFILES);
PdfArray filespecs = embeddedfiles.getAsArray(PdfName.NAMES);
PdfDictionary filespec;
PdfDictionary refs;
FileOutputStream fos;
PRStream stream;
int count = 0;
for (int i = 0; i < filespecs.size(); ) {
filespecs.getAsString(i++);
filespec = filespecs.getAsDict(i++);
refs = filespec.getAsDict(PdfName.EF);
for (Object key : refs.getKeys()) {
fos = new FileOutputStream(String.format("C:\\temp\\"+ filespec.getAsString((PdfName)key).toString()));
attachments[count++] = String.format("C:\\temp\\"+ filespec.getAsString((PdfName)key).toString());
stream = (PRStream) PdfReader.getPdfObject(refs.getAsIndirectObject((PdfName)key));
fos.write(PdfReader.getStreamBytes(stream));
fos.flush();
fos.close();
}
}
reader.close();
}
public void addAttachments(String src, String dest) throws IOException, DocumentException
{
PdfReader reader = new PdfReader(src);
PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(dest));
for (int i = 0; i < attachments.length; i++) {
addAttachment(stamper.getWriter(), new File(attachments[i]));
}
stamper.close();
}
protected void addAttachment(PdfWriter writer, File src) throws IOException {
PdfFileSpecification fs =
PdfFileSpecification.fileEmbedded(writer, src.getAbsolutePath(), src.getName(), null);
writer.addFileAttachment(src.getName().substring(0, src.getName().indexOf('.')), fs);
}
}