why would an application use an image servlet

Question

I have seen some applications that use a servlet to serve the images. What would be the purpose of this?

score 3 · Answer 1 · answered Jun 01 '11 at 12:40

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Possibly to impose user authenication in some way, ie: not all users have the rights to view all images

answered Jun 01 '11 at 12:40

Steve

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score 3 · Accepted Answer · answered Jun 01 '11 at 12:47

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Could be because of following reasons

URL processing required to fetch the image. e.x, fetching the image based on username
The image is stored in database
Some image processing is required like rotate, zoom etc

answered Jun 01 '11 at 12:47

Ramesh PVK

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score 2 · Answer 3 · answered Jun 01 '11 at 12:39

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Dynamically generated images would be an example.

answered Jun 01 '11 at 12:39

Waldheinz

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score 1 · Answer 4 · answered Jun 03 '11 at 17:06

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You can display images packed in your WAR using the path for the image relative to the context root of your application. But for images stored on your hdd (eg: C:\images\picture.jpg), how can you give that path if you can't pass the context root ? If you simply gave the path from your hdd you would get something like this: http://localhost:9080/your-app/C:/images/picture.jpg
So you need to load your image into a byte array on your servlet and then send the content of the picture using the ResponseWriter of the servlet.
It's the only way.

answered Jun 03 '11 at 17:06

Cosmin Cosmin

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There are more ways though. See also http://stackoverflow.com/questions/4543936/load-the-image-from-outside-of-webcontext-in-jsf/4543951#4543951. – BalusC Jun 04 '11 at 03:12
I see, but it's not standard .. it's a feature of some containers, I think ? – Cosmin Cosmin Jun 04 '11 at 10:51

why would an application use an image servlet

4 Answers4