How to access resources in JAR file? - java

I have a Java project with a toolbar, and the toolbar has icons on it. These icons are stored in a folder called resources/, so for example the path might be "resources/icon1.png". This folder is located in my src directory, so when it is compiled the folder is copied into bin/
I'm using the following code to access the resources.
protected AbstractButton makeToolbarButton(String imageName, String actionCommand, String toolTipText,
String altText, boolean toggleButton) {
String imgLocation = imageName;
InputStream imageStream = getClass().getResourceAsStream(imgLocation);
AbstractButton button;
if (toggleButton)
button = new JToggleButton();
else
button = new JButton();
button.setActionCommand(actionCommand);
button.setToolTipText(toolTipText);
button.addActionListener(listenerClass);
if (imageStream != null) { // image found
try {
byte abyte0[] = new byte[imageStream.available()];
imageStream.read(abyte0);
(button).setIcon(new ImageIcon(Toolkit.getDefaultToolkit().createImage(abyte0)));
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
imageStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
} else { // no image found
(button).setText(altText);
System.err.println("Resource not found: " + imgLocation);
}
return button;
}
(imageName will be "resources/icon1.png" etc). This works fine when run in Eclipse. However, when I export a runnable JAR from Eclipse, the icons are not found.
I opened the JAR file and the resources folder is there. I've tried everything, moving the folder, altering the JAR file etc, but I cannot get the icons to show up.
Does anyone know what I'm doing wrong?
(As a side question, is there any file monitor that can work with JAR files? When path problems arise I usually just open FileMon to see what's going on, but it just shows up as accessing the JAR file in this case)
Thank you.

I see two problems with your code:
getClass().getResourceAsStream(imgLocation);
This assumes that the image file is in the same folder as the .class file of the class this code is from, not in a separate resources folder. Try this instead:
getClass().getClassLoader().getResourceAsStream("resources/"+imgLocation);
Another problem:
byte abyte0[] = new byte[imageStream.available()];
The method InputStream.available() does not return the total number of bytes in the stream! It returns the number of bytes available without blocking, which is often much less.
You have to write a loop to copy the bytes to a temporary ByteArrayOutputStream until the end of the stream is reached. Alternatively, use getResource() and the createImage() method that takes an URL parameter.

To load an image from a JAR resource use the following code:
Toolkit tk = Toolkit.getDefaultToolkit();
URL url = getClass().getResource("path/to/img.png");
Image img = tk.createImage(url);
tk.prepareImage(img, -1, -1, null);

The section from the Swing tutorial on How to Use Icons shows you how to create a URL and read the Icon in two statements.

For example in a NetBeans project, create a resources folder in the src folder. Put your images (jpg, ...) in there.
Whether you use ImageIO or Toolkit (including getResource), you must include a leading / in your path to the image file:
Image image = Toolkit.getDefaultToolkit().getImage(getClass().getResource("/resources/agfa_icon.jpg"));
setIconImage(image);
If this code is inside your JFrame class, the image is added to the frame as an icon in your title bar.

Related

Deploying images used in Java Application with the built jar file

After using images for example on a Button, when I build the application creating the .jar file and execute only the file, the images are not there but would only show if I copy the images folder in the same directory as the jar file. Why is that and how can I resolve this if possible?
I am currently using the following code to set the icon/image:
JButton btn = new JButton("Text", "img/icon.png");
The fact that you can use the images when they are stored outside the jar, suggests that you are doing something of the kind:
File image = new File("directory/image.jpg");
InputStream is = new FileInputStream(image);
This reads a file from a directory on the file system, not from the classpath. Now, if you have packaged your image in a "directory" inside your Jar, you must load the image from the classpath.
InputStream is = getClass().getResourceAsStream("/directory/image.jpg");
(note the slash in the path)
Or
InputStream is = getClass().getClassLoader().getResourceAsStream("directory/image.jpg");
(note the absence of the slash in the path)
Your example, as it is now, should not compile. (The second argument of your JButton construtor is an Icon, not a String, java 8). So when you were getting the image from the file system, you were probably doing something else.
With your example, you need to read an image from the inputstream and convert it to an Icon:
try (InputStream is = getClass.getClassLoader().getResourcesAsStream("directory/image.jpg")) {
BufferedImage image = ImageIO.read(is);
return new JButton("Text", new ImageIcon(image));
} catch (IOException exc) {
throw new RuntimeException(exc);
}
That should use the image that is located in "directory" inside your jar. Of course, you need to include the image within your jar, or you will get a NullPointerException on the inputstream is.
I think you need to understand the
ClassLoader:
A typical strategy is to transform the name into a file name and then
read a "class file" of that name from a file system.
So with this you will be able to lead Resources of your project with getResource
public URL getResource(String name)
Finds the resource with the given name. A resource is some data
(images, audio, text, etc) that can be accessed by class code in a way
that is independent of the location of the code.

javafx - load image from within a jar

I'm sorry for asking such a beginner question, but I just can't get it to work and I can't find the answer anywere either.
I want to have an image inside my .jar file and load it. While that sounds simple, I was only able to load an image while running from inside the IDE but not anymore after making the .jar (Thanks to google I was able to get the .png inside the .jar). Here is what I tried:
BorderPane bpMain = new BorderPane();
String fs = File.separator;
Image imgManikin;
try {
imgManikin = new Image(
Main.class.getProtectionDomain().getCodeSource().getLocation().toURI().toString()+"\\manikin.png");
bpMain.setBottom(new Label(Main.class.getProtectionDomain().getCodeSource().getLocation().toURI().toString()+"\\manikin.png"));
} catch (URISyntaxException e) {
imgManikin = new Image(
Main.class.getProtectionDomain().getCodeSource().getLocation().getPath()+"\\manikin.png");
System.out.println(Main.class.getProtectionDomain().getCodeSource().getLocation().getPath()+"\\manikin.png");
bpMain.setBottom(new Label(Main.class.getProtectionDomain().getCodeSource().getLocation().getPath()+"\\manikin.png"));
}
//Image imgManikin = new Image("file:src\\manikin.png");
ImageView imgvBackground = new ImageView(imgManikin);
imgvBackground.setFitWidth(100);
imgvBackground.setPreserveRatio(true);
bpMain.setCenter(imgvBackground);
primaryStage.setTitle("Kagami");
primaryStage.setScene(new Scene(bpMain, 300, 275));
primaryStage.show();
Needlessly to say it didn't work. It is showing me the Label at the bottom with the path just as intended, but it seams like the path just isn't right. (I also tried using the File.seperator instead of \\ and even /, but I got the same result every time: It showes me the path but won't load the image.
I'm using Windows 7, the IDE is IntelliJ and I have the newest Java update.
If the jar file is on the classpath of your application and the image to be loaded is located at the root of the jar file, the image can be loaded easily by:
URL url = getClass().getResource("/manikin.png");
BufferedImage awtImg = ImageIO.read(url);
Image fxImg = SwingFXUtils.toFxImage(awtImg, new Image());
Image fxImgDirect = new Image(url.openStream());
While ImageIO returns a BufferedImage this can be converted to a fx Image using the SwingUtils. However the preferred way is to directly create a new Image instance using the InputStream from the URL.
See also Load image from a file inside a project folder. If done right it does not matter if it is loaded from a jar file or the local file system.
The Image::new(String) constructor is looking for a URL. It is possible to construct a URL for a resource in a jar file, but it's much easier to use ClassLoader::getResource or ClassLoader::getResourceAsStream to manage that for you.
Given the file structure:
src/
SO37054168/
GetResourceTest.java
example/
foo.txt
The following, packaged as a jar will output
package SO37054168;
public class GetResourceTest {
public static void main(String[] args) {
System.out.println(GetResourceTest.class.getClassLoader().getResource("example/foo.txt"));
System.out.println(GetResourceTest.class.getClassLoader().getResourceAsStream("example/foo.txt"));
}
}
jar:file:/home/jeffrey/Test.jar!/example/foo.txt
sun.net.www.protocol.jar.JarURLConnection$JarURLInputStream#7f31245a
Note how the URL for the resource is not the same as the URL you were trying to construct. The protocol is different, and you need to have the ! after the path to the jar file.

JAR file not running when adding images

I was having problems exporting the pictures into the JAR file and after some browsing i found some sollution, but it doesn't seem to be working
try {
//leftFoot = ImageIO.read(new File("resources/leftFoot.png"));
//rightFoot = ImageIO.read(new File("resources/rightFoot.png"));
URL url = this.getClass().getResource("/resources/leftFoot.png");
leftFoot = ImageIO.read(url);
url = this.getClass().getResource("/resources/rightFoot.png");
rightFoot = ImageIO.read(url);
} catch (IOException e) {
e.printStackTrace();
}
}
So, if i try to upload the items from the first two lines(and comment the following 4), the main GUI stuff runs in the JAR file but the images ar not shown. If i do it the other way round(the code above), no GUI element works in the jar file. I have a "resources" folder containing the pictures both in the "bin" folder and in the main folder along bin,src,settings etc. cause i read somewhere that this is how it supposed to be, although i do not know why. leftFoot and rightFoot are BufferedImage objects. Could you tell me what is not working here?

Java jar not reading files from the jar, only external folders?

When ever I make a JAR, the JAR won't read the folder inside it, only a folder in the folder the JAR is it. OK, that wasn't very descriptive. So here is a photo I edited to support.
I hope you get the idea now. So how would I fix this? I already have res and stats part of the build path in eclipse, now what?
Code I use to read the resources:
Image player;
player = new ImageIcon("res/player.png").getImage();
When using ImageIcon and passing it a String, it expects that the parameter refers to a File.
From the JavaDocs
Creates an ImageIcon from the specified file. ... The specified String
can be a file name or a file path
Files and "resources" are different things.
Instead, try using something more like...
new ImageIcon(getClass().getResource("res/player.png"));
Assuming that res/player.png resides within the jar in side the res directory.
Depending on the relationship to the class trying to load the resource and the resource's location, you may need to use
new ImageIcon(getClass().getResource("/res/player.png"));
instead...
Updated
Some recommendations, as EJP has pointed, you should be prepared for the possibility that the resource won't be found.
URL url = getClass().getResource("/res/player.png");
ImageIcon img = null;
if (url != null) {
img = new ImageIcon(url);
}
// Deal with null result...
And you should be using ImageIO.read to read images. Apart from the fact that it supports more (and can support more into the future) image formats, it loads the image before returning and throws an IOException if the image can't be read...
URL url = getClass().getResource("/res/player.png");
ImageIcon icon = null;
if (url != null) {
try {
BufferedImage img = ImageIO.read(url);
icon = new ImageIcon(img);
} catch (IOException exp) {
// handle the exception...
exp.printStackTrace();
}
}
// Deal with null result...

Reference resource in top directory (not package) in Java JAR/Eclipse

I'm trying to access some resources located in the top directory of my (Java) project (/resources/imgname.jpg) from a class 'GUI' located in a package 'gui'.
Originally I used the following code:
ImageIcon image = new ImageIcon("./resources/imgname.jpg");
Image img = image.getImage();
This works fine in Eclipse, but doesn't display the image when it's in a runnable JAR. So after some searching it seems you need:
InputStream resource = GUI.class.getResourceAsStream("./resources/imgname.jpg");
try {
Image image = ImageIO.read(resource);
} catch (IOException e) {//trycatch needed because of read method}
Now this doesn't work in either Eclipse or JAR.
I've tried changing reference and location, but the only way I can get the image to display is by placing it in the 'gui' package folder. So is there any way I can reference it in the top folder of the project instead (so I don't have to move the resources to 'gui')?
Thx,
Magic
Try this.
InputStream resource = GUI.class.getClassLoader().getResourceAsStream("resources/imgname.jpg");
It works for me.

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