How to convert a PDF generating in response.outputStream to a Base64 encoding

Question

I am doing a project where i need to create a admit card for student who are appearing in examination. The pdf Generation part is working fine but my problem is i have to e

Answer 1

When I look at your code, I see:

PdfWriter.getInstance(document,response.getOutputStream());

Which means that you are instructing iText to write PDF bytes straight to the browser. This outputstream is closed at the moment you close the document.

I also see:

OutputStream responseOutputStream = response.getOutputStream();

I even see that you try adding stuff to this stream. This is impossible as the stream is already closed.

You need to create a ByteArrayOutputStream like this:

ByteArrayOutputStream baos = new ByteArrayOutputStream();

And use this in the PdfWriter:

PdfWriter.getInstance(document, baos);

Now you can get the PDF bytes like this:

byte[] pdf = baos.toByteArray();

Now you can encode these bytes and send them to the output stream.

Encode:

Assuming that you are using org.apache.commons.codec.binary.Base64 as explained in the answer to Base64 Encoding in Java, you can do this:

byte[] base64 = Base64.encodeBase64(pdf);

(There are other ways to do this.)

Send to output stream:

response.setHeader("Expires", "0");
response.setHeader("Cache-Control",
            "must-revalidate, post-check=0, pre-check=0");
response.setHeader("Pragma", "public");
response.setContentType("application/pdf");
response.setContentLength(base64.length);
OutputStream os = response.getOutputStream();
os.write(base64);
os.flush();
os.close();