Java can't find non-java files

Question

I am using gradle for building 2D game project. I have set up gradle, but when I add images and txt files to resources folder I get FileNotFoundException: levels/level1_path.txt (No such file or directory).

I CAN NOT use GameEngine.class.getResource("levels/level1_path.txt").getFile(), because there are more than 100 pictures and icon in the game, it would be wrong. I need to find a way such that new File("levels/level1_path.txt") works.

My gradle:

plugins {
    id 'java'
}

group 'org.example'
version '1.0-SNAPSHOT'

repositories {
    mavenCentral()
}

sourceSets {
    main {
        resources {
            srcDirs = ['src/main/resources']
        }
    }
}

dependencies {
    testCompile group: 'junit', name: 'junit', version: '4.12'

    // slick 2d
    compile files('/Users/faridganbarli/Downloads/slickLIB/lib/jinput.jar')
    compile files('/Users/faridganbarli/Downloads/slickLIB/lib/lwjgl.jar')
    compile files('/Users/faridganbarli/Downloads/slickLIB/lib/lwjgl_util.jar')
    compile files('/Users/faridganbarli/Downloads/slickLIB/lib/slick.jar')

}

My function:

private int[][] initLocations() throws FileNotFoundException{
        File file = new File("levels/level1_path.txt");
        Scanner sc = new Scanner(file);
        int[][] loc=new int[sc.nextInt()][2];
        for(int i=0; i<loc.length; i++){
            loc[i][0]=sc.nextInt();
            loc[i][1]=sc.nextInt();
        }
        return loc;
    }

Answer 1

Here is a way to do it:

I would create a Map for each type of resource, and this will be a mapping of the form: folder/with/resource.ext -> uri:///actual/path/to/folder/with/resource.ext where folder is a folder within your resources . In your case, folder could be something like levels .

Now in your code, create these structures and put them somewhere they cannot be modified

public static final Map<String, URI> IMAGE_RESOURCES = Collections.unmodifiableMap(loadAllResources("images"));
public static final Map<String, URI> PATH_RESOURCES = Collections.unmodifiableMap(loadAllResources("levels"));

Now we define a function that will load all resources from a given folder and have them all available for easy access.

private static Map<String, URI> loadAllResources(String folder) {
    ClassLoader loader = Thread.currentThread().getContextClassLoader();
    URL folderUrl = loader.getResource(folder);

    final Path root = Paths.get(folderUrl.toURI()).getParent();

    return Files.walk(Paths.get(folderUrl.toURI()))
                .filter(Files::isRegularFile)
                .collect(Collectors.toMap((p)-> root.relativize(p).toString(), Path::toUri));
}

Now assuming the following folder structure in your resources folder:

.
├── images
│   ├── foo.png
│   └── bear.png
└── levels
    └── level1_path.txt

You can load the file level1_path.txt by doing:

new File(PATH_RESOURCES.get("levels/level1_path.txt"));

References:

• https://stackoverflow.com/a/24006711/2089675
• https://www.logicbig.com/how-to/java/list-all-files-in-resouce-folder.html