Calculating Compressed Filesize from GZIPOutputStream

Question

I am compressing File and writing it into outputstream, How to get the compressed file size to put in response header

    os = response.getOutputStream();
    gzos = new GZIPOutputStream(os);
    fin = new FileInputStream(file);
    in = new BufferedInputStream(fin);

    byte[] buffer = new byte[1024];
    int i;
    while ((i = in.read(buffer)) >= 0) {
           gzos.write(buffer, 0, i);
     }
    gzos.flush();

score 1 · Accepted Answer · answered Sep 13 '12 at 06:34

you don't. Reason:

response will be committed once response buffer is full, that is to say, if you are gzipping a 20MB large file, the header was already sent to client before gzip completes, and you can not modify the committed header when gzip finishes.

score 0 · Answer 2 · answered Sep 13 '12 at 06:30

0

You should Look at fin.Position

answered Sep 13 '12 at 06:30

MichaelT

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score 0 · Answer 3 · answered Sep 13 '12 at 06:36

0

You don't. Reason: you don't have to. The servlet container takes care of it for you.

answered Sep 13 '12 at 06:36

user207421

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i didn't find any content length in response headers. I want to display progress bar in android so that i need content length while downloading. Is it possible without content length. – Dyapa Srikanth Sep 13 '12 at 07:11

Calculating Compressed Filesize from GZIPOutputStream

3 Answers3