[JAVA] Include image resources in jar file

Image disappears when outputting jar file from IntelliJ

When I made a GUI tool using Swing, the image file was displayed properly when it was executed on IntelliJ, but I faced the problem that the image file could not be displayed properly when it was output as a jar file. When I googled, it seemed to be a well-known phenomenon, and a solution came out immediately. The following is a summary of the solution as a memo for myself.

Situation explanation

To practice Swing, Java's GUI toolkit, I created a simple program that only displayed an hourglass icon. スクリーンショット 2020-01-22 10.42.20.png Like this

The icon is named hourglass.png file and saved directly under the src folder. In addition, the reading of the icon file is described as follows. ImageIcon myIcon = new ImageIcon("hourglass.png "); スクリーンショット 2020-01-22 10.49.04.png

Running this code on IntelliJ will run the program with the hourglass icon properly displayed. However, when I output the jar file and execute the program from the terminal, the icon cannot be displayed as shown below.

スクリーンショット 2020-01-22 11.23.16.png


Use ClassLoader.getResource ().

In Java, ClassLoader.getResource () is prepared as a process to acquire resource information such as files.

In the previous code, ʻImageIcon myIcon = new ImageIcon ("hourglass.png "); `

ClassLoader cl = this.getClass().getClassLoader();
ImageIcon myIcon = new ImageIcon(cl.getResource("hourglass.png "));

By rewriting as, even after outputting as a jar file, the image resource will be referenced properly, so the image will be displayed. スクリーンショット 2020-01-22 10.42.20.png I did it

Reference source

https://virtualwalk.hatenadiary.org/entry/20121013/1350127275 http://hiesuke.hatenablog.com/entry/2016/12/30/101639

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