hi,
I have a couple of files from which I want to create BufferedImage so
that I can display it on a jpanel.Problem is that their extensions are
unreliable.
/myimgs/image1.png

/myimgs/realimage2.txt

/myimgs/fakeimage3.png

the first two are actual png images and the last one is a text file
renamed as .png
Is there some way to test for the valid images?

I tried this

public boolean checkIfImageFile(String filename){
	boolean isimage=false;
	try{
		BufferedImage bi=ImageIO.read(new File(filename));
		if (bi!=null)isimage=true;
	}catch(Exception e){
		isimage=false;
	}

	return isimage;
}

Is this the way to do such a test?If there is a proper way please tell
me.
thanks in advance
sajan

On 10/28/2010 10:25 AM, damon wrote:
> the first two are actual png images and the last one is a text file
> renamed as .png
> Is there some way to test for the valid images?


What you have probably works well enough.  I would open the file and 
look for magic numbers and such, first, as it might be faster/less CPU. 
  As long as what you have seems to actually function, I don't see a 
reason to change it.

On 28-10-2010 13:25, damon wrote:
> I have a couple of files from which I want to create BufferedImage so
> that I can display it on a jpanel.Problem is that their extensions are
> unreliable.
> /myimgs/image1.png
>
> /myimgs/realimage2.txt
>
> /myimgs/fakeimage3.png
>
> the first two are actual png images and the last one is a text file
> renamed as .png
> Is there some way to test for the valid images?
>
> I tried this
>
> public boolean checkIfImageFile(String filename){
> 	boolean isimage=false;
> 	try{
> 		BufferedImage bi=ImageIO.read(new File(filename));
> 		if (bi!=null)isimage=true;
> 	}catch(Exception e){
> 		isimage=false;
> 	}
>
> 	return isimage;
> }
>
> Is this the way to do such a test?If there is a proper way please tell
> me.

The technique looks fine.

I may have written the code slightly different, but it does not matter.

Arne

On Thu, 28 Oct 2010 10:25:29 -0700 (PDT), damon
<sajanjoseph@gmail.com> wrote, quoted or indirectly quoted someone who
said :

>
>the first two are actual png images and the last one is a text file
>renamed as .png
>Is there some way to test for the valid images?

Have a look at the code in the ImageInfo class part of the Common11
package you can download at
http://mindprod.com/products1.html#COMMON11
-- 
Roedy Green Canadian Mind Products
http://mindprod.com

Microsoft has a new version out, Windows XP, which according to everybody is the "most reliable Windows ever." To me, this is like saying that asparagus is "the most articulate vegetable ever." 
~ Dave Barry