Java web server and PDF files

Question

I have created my own HTTP server. I need to return a PDF file (generated by Jasper Reports) to the web browser. However, when I read the PDF file and write its contents to the socket, the web browser receives a blank PDF file. When I save this file and compare it to the original, I see that many of the characters have been converted from their original value to 0x3F (which is '?').

When I read the file, my debug output shows that the correct values are read and that the correct values are written to the socket. Can anyone help me?

Here is the code (minus all the debug code) that reads the PDF file:

File f = new File(strFilename);
long len = f.length();
byteBuffPdfData = ByteBuffer.allocate( (int)len );

FileInputStream in = new FileInputStream(strFilename);

boolean isEOF = false;
while (!isEOF)
{
    int iValue = in.read();
    if (iValue == -1)
    {
 isEOF = true;
    }
    else
    {
        byteBuffPdfData.put( (byte)iValue );
    }   
}

---

Next is the code that writes from the byte buffer to the socket...

printWriter = new PrintWriter( socket.getOutputStream(), true );
printWriter.write(strHttpHeaders);
// Headers:     
// HTTP/1.0 200 OK
// Date: Wed, 18 Nov 2009 21:04:36
// Expires: Wed, 18 Nov 2009 21:09:36
// Cache-Control: public
// Content-Type: application/pdf
// Content-Length: 1811
// Connection: keep-alive
//

byteBuffPdfData.rewind();
while(byteBuffPdfData.hasRemaining())
{
    printWriter.print( (char)byteBuffPdfData.get() );
}
printWriter.flush();
socket.close();

Any help that can be offered is greatly appreciated. I am sure that I need to do something with the character sets but at this point I have tried a million things and nothing seems to work.

John

Answer 1

I'm not sure what language you're writing in here (looks like Java, though), but is it possible something is trying to do a charset conversion (perhaps to or from Unicode characters)? The ? seems reasonable as a 'substitution' for characters that can't be represented in ASCII. (I recognize that you aren't deliberately trying to do any such conversion, but maybe something of the sort is happening in the libraries you're using.)