使用 Java 中的 itext 将 pdf 保存到字节数组

Question

I am using itext to read a large pdf file and save selected pages.

PdfReader reader = null;
reader = new PdfReader("customPath/largePdf.pdf");
int pages = reader.getNumberOfPages();
List<Integer> pagesList = new ArrayList<Integer>();
pagesList.add(1);
pagesList.add(2);
reader.selectPages(pagesList);
String path;
PdfStamper stamper = null;
path = String.format("customerPath/split.pdf");
stamper = new PdfStamper(reader, new FileOutputStream(path));

All good until now, i can open the split.pdf.

Now, Instead of saving to a file, i want to save it to a bytearray (so that i can save it as a blob later)

Tried this:

PdfReader reader = null;
reader = new PdfReader("customPath/largePdf.pdf");
int pages = reader.getNumberOfPages();
List<Integer> pagesList = new ArrayList<Integer>();
pagesList.add(1);
pagesList.add(2);
reader.selectPages(pagesList);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
PdfStamper stamper2 = new PdfStamper(reader, baos);
byte[] byteARy = baos.toByteArray();

Just to make sure it works, i tried writing this bytearray to a file:

OutputStream out = new FileOutputStream("customPath/fromByteArray.pdf");
out.write(byteARy);
out.close();

fromByteArray.pdf does not open and the size is zero, any idea what might be wrong?

Answer 1

You retrieve the byte array (using baos.toByteArray() ) immediately after creating the PdfStamper .

PdfStamper stamper2 = new PdfStamper(reader, baos);
byte[] byteARy = baos.toByteArray();

At that time there is (next to) nothing in the output. You must instead wait until after closing your PdfStamper to retrieve the output.

PdfStamper stamper2 = new PdfStamper(reader, baos);
...
stamper2.close();
byte[] byteARy = baos.toByteArray();

Now the byte array should contain the complete, stamped PDF.