I do not know what your filecontentVO is doing. But could you try working with a fixed lenth byte array like:
byte[] buff = new byte[128];

and use a code similar to the following to read up the byte array and write that array in the next line to the servlet output stream (or the buffering wrapper) in a loop:

inStream .read(ByArray,...);

outStream.write(ByArray,....);

The idea is not to wait till the entire file is read by the instream before starting the writing as was happenning in your case. Better is: Read a few bytes, push them into the outstream and again read and then write .... like this.

You may try...

Regards,
Partha

-----Original Message-----
From: A mailing list for Java(tm) 2 Platform, Enterprise Edition
[mailto:J2EE-INTEREST@JAVA.SUN.COM]On Behalf Of Jean-Christian Imbeault
Sent: Friday, January 07, 2005 10:48 AM
To: J2EE-INTEREST@JAVA.SUN.COM
Subject: Performance of BufferedOutputStream.write()


For security reasons we don't allow our users direct access to pdf files
located on our application server. They have to request them through a
servlet and then the servlet streams the file back to the client.

However we have some performance issues. Files take a long time to
streamed compared to the time it takes to get the file if it's served up
as a file (a direct URL to the file). a 200kb file might take 2 s to
load from a link but about 10 s when going through the servlet.

We're not sure if the performance problem is a direct result of using a
servlet to stream the file (i.e. you need to first read the file, then
stream it) or some other problem with our application configuration.

Can someone give me their opinion on the following servlet code?

Two things I am wondering about are:

#1- passing a file around in the request object is a bad thing, or a
performance issue
#2- streaming the file is not very efficient

I think #1 might be an issue especially considering that the files ar
from 200kb - 2Mb. Putting such a large object into memory just doesn't
seem right.

As for #2 I don't know. A web server basically as to read the file and
then stream it anyway so there should be much difference if I usurp the
web server and do all the file reading and streaming myself...

Thanks,

Jc

==The code==


public class FileDownloadServlet extends HttpServlet {
public void doPost(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException {

ServletOutputStream out = res.getOutputStream();
FileContentVO fileContentVO =
(FileContentVO) req.getAttribute(AppConstants.OUTPUT_OBJECT);
Str ing fileName = fileContentVO.getFileName();

/********** preventing browser from caching **********/

res.setHeader("Pragma", "No-cache");
res.setDateHeader("Expires", 0);
res.setHeader("Cache-Control", "no-cache");

/***********************End***************************/

res.setContentType("application/pdf");
res.setHeader("Content-disposition", "inline; filename=" +
fileName);

BufferedOutputStream bos = null;
byte[] buff = null;

try {
bos = new BufferedOutputStream(out);

/* the file was read from disk and put in the VO */
buff = fileContentVO.getFileContent();
bos.write(buff, 0, buff.length);

if (bos != null) {
bos.close();
}

}
catch (final MalformedURLException e) {
throw e;
}
catch (final IOException e) {
throw e;
}
catch (Exception e) {
}
finally {
buff = null;
}
}
}


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