将Java文件编译为jar文件后，为什么图像路径不再起作用？

Question

I have a relatively basic java program which uses a system tray icon. The path I was using while writing the code is as follows "../images/logo.png" . However, when I compile it into a jar file, the image does not show up in the system tray. Instead, if I change the path to "./images/logo.png" , then the image shows up in the system tray when it's in the jar file form, but not while I'm testing.

It's not a major issue. However, I am curious to know why this inconsistency occurs.

Answer 1

When you package your program into a .jar file, your build is most likely copying the image into the same directory as the .jar file. However, when debugging in your ide, your image file lies one directory below.

Another possibility is that you are simply setting your Working Directly differently in the two scenarios.

Incidentally, you might be interested in embedding the image in your jar file, see: https://stackoverflow.com/a/1096491/24954

Answer 2

This answer depends on two things. If the image file is embedded or not.

Embedded Resource

Once you have Jar'ed your application and the images are emebbed inside the application, normal file access methods will no longer work.

Trying to do something like...

new ImageIcon("../images/logo.png");

or

new File("../images/logo.png");

Won't work. This is because the resource is no longer a file within the context of the file system (it's actually a Zip entry in the Jar).

Instead, you need to use Class#getResource which will return a URL to the embedded resource.

new ImageIcon(getClass().getResource("../images/logo.png"));

Will work better. In general though, it is recommended to use an absolute path to the resources new ImageIcon(getClass().getResource("/images/logo.png")); as it's generally more difficult to break (IMHO)

External Resource

The path to the image is relative to the execution point of the application.

In development, you may have had to move up a directory (out of the src folder presumably) to find the image resource. This will mean that you will need to store you Jar file in a folder that would require it step up one level before it could find the image resource.

If you can, it's generally better to embedded the resource within the Jar where possible. It makes it easier to deploy as you reduce the number of files you need to package and makes it (a little) harder for the user to mess with it ;)

Answer 3

无法识别图像的路径，因此可以使用此代码

jLable1.setIcon(new javax.swing.ImageIcon(getClass().getResource("/Client/images/images/button_ok.png")));