IOUtils.toByteArray() OutOfMemoryError

Question

i try to compress large video file with more than 100Mb in size.

public static void compress(File input, File output) throws    IOException {
        InputStream fis = new FileInputStream(input);
        byte[] bFile = IOUtils.toByteArray(fis);
        FileOutputStream fos = new FileOutputStream(output);
        GZIPOutputStream gzipStream = new GZIPOutputStream(fos);
        try {
            gzipStream.write(bFile);
            // IOUtils.copy(fis, gzipStream);
        } finally {
            gzipStream.close();
            fis.close();
            fos.close();
        }           
    }

every time i got outofmemoryerror.

Answer 1

You should copy the data progressively and you won't run out of memory.

public static void compress(File input, File output) throws IOException {
    try(InputStream in = new FileInputStream(input);
        OutputStream out = new GZIPOutputStream(new FileOutputStream(output))) {
        byte[] bytes = new byte[4096];
        for(int len; (len = in.read(bytes)) > 0; )
            out.write(bytes, 0, len);
    }           
}

This will use about 4 KB as a buffer at once, regardless of the size of the file. (I suspect the GZIP uses about the same to do it's work)