How many ways are there to get the Width/Height of an image ?

Question

I am currently using the following code to get the width and hight of an image :
BufferedImage Buffered_Image=ImageIO.read(new File(Image_Path));
int Image_Width=Buffered_Image.getWidth();
int Image_Height=Buffered_Image.getHeight();I don't need to get the image (*.jpg, *.gif, *.png), just want to know it's dimensions. I wonder how many other ways are available to do the same thing in a Java application ?
Frank

Answer 1

Ni_Min wrote:
That's what I thought. I am asking because I hit a wall and am trying to find a different approach.Yeah, if you only have one file type you can probably write the code to read the header in 20 min.
I packed my programs into an executable Jar file which I can run and access images on my C:\ drive, everything worked fine until I tried to experiment with something new. I know that I can force JVM to pre-load all my java classes just after it starts, so I deleted the jar right after the program pre-loaded all my classes and tried to see if it would work, but now I get a null pointer error when it tried to get the width/height of an existing image, because ImageIO.read return null. ( The same image is still on my C:\ drive )Sounds like a strange thing you're doing here. What's the point of this?
So I wonder why it makes a difference after I deleted the jar, what was the problem ( or do I need to pre-load another class related to ImageIO.read ? ), and maybe if I use something else other than the ImageIO.read to get the width/height, I can bypass the problem.I dunno why you need to do this preload stuff and/or delete anything. I'd say leave the JVM and the app alone if possible.