Read images from a jar file?

Hello, I'm converting a 6i app to 10g. This app does a ton of read_image_file() calls to
change GIF images on the screen based on user actions. In 6i the images are all stored on the local hard drive. The images are not icons for buttons, but images that appear in different locations on the screen.
For 10g, is it possible to leave the images in a jar file and effectively read the images from that? Otherwise, I suppose I'm looking at using webutil functionality to download the jar file and unjar it into an images directory for reading from the client?
Any best-practice scenario for this sort of thing?
Thanks for any info,
Gary

We are migrating from 6i to 10g too. And I try to not use webutil. All my pictures (icons gif files) are in a jar file.
Just make attention of the size of your pictures. The jar file is loaded when you launch the application (the first time, and after, only if the jar file has changed).

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Read images from external jar file (Sun's Java L&F Graphics repository)

Hi!
I don't know how to read images from an external jar file. Sun has a Java Look and Feel graphics repository that contains a lot of good images that can be used on buttons and so on. This repository is delivered as a jar file, containing only images, and I want to read the image files from that jar file directly without including them inside my application jar file. The application and image jar files will be in the same directory.
I have absolutely no clue how to solve this. Is it necessary to include the images inside my application jar file or is it possible to have them separate as I want.
Would really appreciate some help!
Best regards
Lars

Hi,
There is two ways :
1) Add your jarfile to the classpath.
Use the class loader :
URL url = ClassLoader.getSystemResource("your/package/image.gif");
Image im = (new ImageIcon(url)).getImage();
or
Image im = Toolkit.getDefaultToolkit().getImage(url);2)If you don't want to add the jar to the classpath you can use this (under jdk 1.4):
import java.util.*;
import java.util.jar.*;
import java.awt.*;
import java.io.*;
import java.awt.image.*;
import javax.imageio.*;
public class ImageUtilities {
     public static Image getImage(String jarFileName, String fileName) {
          BufferedImage image = null;
          try {
               JarFile jar = new JarFile(new File(jarFileName), false, JarFile.OPEN_READ);
               JarEntry entry = jar.getJarEntry(fileName);
               BufferedInputStream stream = new BufferedInputStream(jar.getInputStream(entry));
               image = ImageIO.read(stream) ;
          catch (Exception ex) {
               System.out.println(ex);
          return(image);
}I hope this helps,
Denis

Issues with Loading Images from a Jar File

This code snippet basically loops through a jar of gifs and loads them into a hashmap to be used later. The images all load into the HashMap just fine, I tested and made sure their widths and heights were changing as well as the buffer size from gif to gif. The problem comes in when some of the images are loaded to be painted they are incomplete it looks as though part of the image came through but not all of it, while other images look just fine. The old way in which we loaded the graphics didn't involve getting them from a jar file. My question is, is this a common problem with loading images from a jar from an applet? For a while I had tried to approach the problem by getting the URL of the image in a jar and passing that into the toolkit and creating the image that way, I was unsuccessful in getting that to work.
//app is the Japplet
MediaTracker tracker = new MediaTracker(app);
//jf represents the jar file obj, enum for looping through jar entries
Enumeration e = jf.entries();
Toolkit toolkit = Toolkit.getDefaultToolkit();
//buffer for reading image stream
byte buffer [];
while(e.hasMoreElements())
fileName = e.nextElement().toString();
InputStream inputstream = jf.getInputStream(jf.getEntry(fileName));
buffer = new byte[inputstream.available()];
inputstream.read(buffer);
currentIm = toolkit.createImage(buffer);
tracker.addImage(currentIm, 0);
tracker.waitForAll();
images.put(fileName.substring(0, fileName.indexOf(".")), currentIm);
} //while
}//try
catch(Exception e)
e.printStackTrace();
}

compressed files are not the problem. It is just the problem of the read not returning all the bytes. Here is a working implementation:
InputStream is = jar.getInputStream(entry);
ByteArrayOutputStream os = new ByteArrayOutputStream(1024);
try{
byte[] buf = new byte[1024];
int read;
while((read = is.read(buf)) > 0) {
os.write(buf, 0, read);
catch(Exception e){
e.printStackTrace();
return null;
image = Toolkit.getDefaultToolkit().createImage(os.toByteArray());
This works but I think you end up opening the jar a second time and downloading it from the server again. Another way of getting the images is using the class loader:
InputStream is = MyApplet.class.getResourceAsStream(strImageName);
In this case, the image file needs to be at the same level than MyApplet.class but you don't get the benefit of enumerating of the images available in the jar.

? SplashScreen - retrieving an image from a jar file ?

When you want to use the Java SplashScreen you provide a run flag of the form:
-splash:image.png
Is there a way to have the 'image.png' reference a file in one of the jar files?I don't believe the jar files are loaded by the time SplashScreen activates so that might be why I can't seem to be able to do it, but that was when I checked over a year ago ... have things changed?
Alternatively (and probably the preferred option for me) is there a way to tell the SplashScreen to create an empty splash so that one exists when I use the 'splash.setImageUrl()' method? Currently I have to set the splash image to be some empty/transparent image via:
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Then I set my own desired image via the 'splash.setImageUrl()' method...BUT, I still need to have the 'empty.png' file contained in the root folder of my project and this sucks. I'd like to be able to tell java that I want to create an empty splash, without having to provide an empty image, and then when the splash is created, I can use the image url method as normal to write my own image to the splash display.
thx.

morgalr, this is independent of code, it's just the splash screen that start up before any code runs so you could do this with any of your projects that you have.
You need to specify splash image via run command of:
-splash:image.png
so, if you have a jar file that has an image in it, and you place it on your classpath and then try to run your code with
-splash:package/path/image.png
it doesn't seem to work...you'll know because either you'll see a splash screen or you won't. Note that the splash screen disappears the first time an AWT/Swing event is encountered (ie a frame is displayed, etc) so it may only last a few milliseconds but it still should come up. All of the links that discuss this talk about specifying a path to an images directory, but this images directory has to be in your project root folder and not in the source tree (as best as I can tell through experimentation).
I guess what I would ultimately want would be to be able to create a SplashScreen instance through each program in my project without having to provide a runtime flag that only generates the instance if the provided image is available. If I it still provided a SplashScreen instance then I would be able to use the setImageUrl() method from code to provide the desired image. Also, it would be nice if the splashscreen remained some set time even after the application window popped up with an AWT/Swing event that now causes it to disappear instantly...but that one I can overcome with my own JWindow post-splash display that mimics the effect.
thanks.

Loading images from a jar file

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My application displays images, until it's placed in a JAR file, then it can't display them even though the JAR file contains the images.
I saw this problem in a previous question which was solved using
URL url = MyClass.class.getResource("abc.gif");
Image img=Toolkit.getDefaultToolkit().getImage(url);
....which btw didn't work for me either......
This method should be made obsolete using ImageIcon, which I am using, but the images still won't appear...
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It works fine that way (...getClass().getResource....) until I create the jar file, and then I get a null pointer exception when it tries to load the image.
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once in a jar file i inserted a image
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===============================================
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thanx
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Afternoon all,
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Is it possible to load classes from a jar file

Using ClassLoader is it possible to load the classes from a jar file?

URL[] u = new URL[1] ;
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Hello,
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Read images from a jar file?

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