> Od: "Nikolaos Giannopoulos" <nikol...@brightminds.org>
> Komu: Stripes Users List <stripes-users@lists.sourceforge.net>
> Datum: 27.07.2010 18:29
> Předmět: Re: [Stripes-users] File Download
>
>Radim,
>
>
>Radim wrote:
>> Hi,
>> first, excuse my english. I'm just a beginner.
>>
>Your English is just fine ;-)
>
>> I have a problem with file download. I'm trying to do file upload and
>> download to/from server. File upload works just fine. But I have a probelm
>> with download. I used StreamingResolution with InputStream. Something like
>> this:
>>
>> public Resolution get() {
>> InputStream is = null;
>> try {
>> is = new FileInputStream(new File(filePath));
>>
>It is quite amazing that there are so many code examples and questions
>pertaining to reading input streams and not wrapping them in buffered
>input streams all over the net and even in some books. Even if this
>doesn't fix your issue it will be HUGE in improving the reading of files
>a fraction of the size of the ones you are using.
>
>Something like (off the top of my head):
>BufferedInputStream is = new BufferedInputStream(new FileInputStream(new
>File(filepath)));
>
>The wonderful thing about OO is that from that point onward "is" is just
>an InputStream so the rest of your code need not change... .
>
>> } catch (FileNotFoundException ex) {
>> Logger.getLogger(MyActionBean.class.getName()).log(Level.SEVERE,
>> null, ex);
>> }
>> return new StreamingResolution(fileType, is);
>> }
>>
>> But if the file is larger than something around 70 or 90 MB, java throws
>> "java.lang.OutOfMemoryError: Java heap space". It seems like Java is trying
>> to load whole file to RAM and then send it to browser. But I would like to
>> work with large files - 2 GB.
>>
>Although I haven't looked at the code of StreamingResolution I imagine
>just by its name that it will chunk read and send the contents of the
>input stream otherwise it wouldn't be called StreamingResolution.
>Buffering is probably your problem or you are hitting this bug (which
>buffering might fix):
>
>http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6478546
I tried the version with BufferedInputStream and it looks same.
The server just send first 70 - 90 MB of file and then throws
java.lang.OutOfMemoryError: Java heap space.
>
>BTW what are your JVM settings / options? e.g. your min heap, max heap,
>etc....
I'm not sure, but in Glassfish is: JVM Settings -> JVM Options -> "-Xmx512m".
>
>> Is there any way to send large file to browser?
>>
>Well there is the "obvious" way. Provide the user a URL to it and let
>the web browser handle it. But this requires some conditions such as that:
>a) The file is in a place that the web / app server can directly access
>it (i.e. not in the database)
>b) A URL can be formed to it (some people have issues here in that they
>want to protect the file and hence stream it).
Yes, I probably will do it this way. But I need some kind of security. Some
files can be available to specific users. Maybe randomly generated names
of files and periodically renaming will do the thing.
>
>Out of curiosity what are you streaming that is 70-90MB. I frequently
I tried this with 200 MB large file. But I need to send even larger files. 2 -
3 GB.
>see people new to Java or a framework and it appears the first thing
>they want to stream is massive files. Files that large should ideally be
>handled by the web / app server... and in the process it improves
>overall performance all around because they typically are better coded /
>optimized to handle it.
>
>HTH,
>
>--Nikolaos
>
>> Thanks,
>> Radim
>>
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>
>
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