JSON Binary Array to Image in Java

Question

I'm consuming a .NET json service that outputs a byte array. The byte arrary gets converted into the integer representation of each byte. When viewed in Fiddler, it looks like this:

{"imageBackground":[137,80,78,71,13,10,26,10,0,0,0,13,73,72,68,...]}

In Java, I've got the data back into a JSONObject, but I'm unfamiliar with Java so I'm not sure where to go from here to convert that into something usable. I suspect if I can get it back into a stream of some sort I should be able to make it viewable as an image (PNG/JPG/etc)...

Any tips form here?

I'm a little disturbed by the idea that anybody is sending an image that way in the first place. (A JSON string of Base64'ed data would be much better.) — Darien
– Darien, Commented Jun 17, 2011 at 19:11

stevevls · Accepted Answer · 2011-06-17 19:03:48Z

2

Get imageBackground as a byte array, and then hand it off to ImageIO:

byte[] imageBackground = // set me here;
ByteArrayInputStream input = new ByteArrayInputStream(imageBackground);
try {
    BufferedImage ImageIO.read(input);
    // do fun stuff with the image...
}
finally {
    input.close();
}

I'm not sure what your application wants to do as the image, but once you have a BufferedImage you can use ImageIO to convert it to another type, you can do transforms, output to a file...the sky's the limit. You can find a tutorial for that and more by Googling.

answered Jun 17, 2011 at 19:03

stevevls

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3 Comments

stevevls Over a year ago

@Andrew Heh heh...I know the feeling.

bugfixr Over a year ago

Are there any java functions available to facilitate getting the string of integers back into a byte[]?

stevevls Over a year ago

certainly... String.getBytes(). there are two signatures...one which returns in the default character encoding (UTF-16) and another where you can specify the encoding.

Bart van Heukelom · Accepted Answer · 2011-06-20 18:17:41Z

0

Something like this (the methods names are probably incorrect, don't know them from the top of my head)

JSONArray jBytes = theObject.getArray("imageBackground");
byte[] imData = new byte[jBytes.size()];
for (int i = 0; i < jBytes.size(); i++) {
   imData[i] = jBytes.get(i);
}

That's how you make it a real byte array. Then do what stevevls posted, or whatever you want.

answered Jun 20, 2011 at 18:17

Bart van Heukelom

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