Retrieve images from a folder outside web root folder using servlet

Question

I'm trying to create a small servlet that uploads images and is able to retrieve them in a different page as a slideshow.

I'm able to save them outside the WebApp folder, but while retrieving them I need them to be a part of a JSP which will have other content, apart from the images. Currently, I'm using BufferedImage and ImageIO classes to stream the images one at a time.

BufferedImage image = ImageIO.read(new File("D:\\"+file.getName())); ImageIO.write(image, "jpg", response.getOutputStream());

The file is checked to be a JPEG file type earlier in the code.

You shouldn't use ImageIO: you're reading bytes representing a JPG-encoded image, then transforming the stream of bytes into a BufferedImage, then transforming this buffered image into bytes representing a JPG-encoded image. Just read the bytes and send them as is to the response output stream. — JB Nizet
– JB Nizet, Commented Jun 13, 2012 at 10:59
Yeah I've tried that as well by simple reading them using BufferedInputStream and then writing it using BufferedOutputStream. That gives me the same end result. What I want to have is a list of images and not a single image. — Batman
– Batman, Commented Jun 13, 2012 at 11:16

JB Nizet · Accepted Answer · 2012-06-13 11:26:43Z

You need to understand how HTTP and HTML work:

The browser asks for an HTML page (first request)
The server sends back HTML (and HTML only), containing 3 <img src="..."/> tags
The browser sends a request to get the bytes of the first image (second request)
The server sends back the bytes of the first image
The browser sends a request to get the bytes of the second image (third request)
The server sends back the bytes of the second image
The browser sends a request to get the bytes of the third image (fourth request)
The server sends back the bytes of the third image

So, you need a servlet or JSP which generates the HTML page, containing all your <img src="..."/> tags. Each of this tag should have the following form:

<img src="imageServlet?imageId=564"/>

And you need a second servlet, mapped to imageServlet, which reads the bytes of the image identified by the imageId parameter value from the file system, and write those bytes to the response output stream.

Jigar Joshi · Accepted Answer · 2012-06-13 10:53:46Z

1

them I need them to be a part of a JSP which will have other content,

Use image tag in JSP

<image src="/context-root/YourServlet?param=value" alt="blah blah"/>

answered Jun 13, 2012 at 10:53

Jigar Joshi

241k42 gold badges409 silver badges446 bronze badges

1 Comment

Batman Over a year ago

I need to have multiple such image tags. How do I generate them at runtime?

Collectives™ on Stack Overflow

Retrieve images from a folder outside web root folder using servlet

2 Answers 2

Comments

1 Comment

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

1 Comment

Linked

Related