getResourceAsStream 返回具有正确路径的 null

Question

my piece of code:

private InputStream assetFromJAR(String fileName) {
    return getClass().getResourceAsStream("/view/assets/ims/" + fileName + ".png");
}

returns always null...

My structure is:

src
  main
   java  <- source root
     view
       assets
         ims

it does not make sence why is this happening, path is correct so why does it always return null?

Thanks for answers!

Answer 1

Maven java projects are structured in way to separate the *.java files and resource files(like *.properties, *.jpg, *.png, etc..)

• For *.java files: src/main/java folder
• For resources: src/main/resources

So place your resources files directly under "src/main/resources" or sub folder of resources directory(like "src/main/resources/view/assets/ims/" for your project).

Then you can easily access the resource files.

private InputStream assetFromJAR(String fileName) {
     return getClass().getResourceAsStream("/view/assets/ims/" + fileName + ".png");
}

Answer 2

I'm going to start with some things that are obvious, because you haven't indicated what you've tried. I apologize if you've done, or are aware of this:

Paths that begin with "/" are found somewhere in the class path. Paths without the beginning "/", start from where the code is called. Your class path roots may not be what you think they are, or the.png file is not being moved from your source directory to your target directory.

Have you verified the file is in the target directory ( assuming your using maven for building), or wherever your.class files end up?

Have you verified what you're class path roots are?