How to get the file in a resource folder

In a Maven project, we may often struggle to get a certain file (e.g. json file or sql file). Here is how to place the resource file and use it in the java class.

1. If the main class is in folder src/main/java/, the resource file should be placed in the folder src/main/resources/

Suppose the main class is GeneralTest.class and the file to be used is under src/main/resources/stories/simple-upgrades/retry-upgrade-file.story

Then the java program should be as follows

import java.io.File;
import java.net.URISyntaxException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class GeneralTest {

    protected String getStoriesDirectoryWithinResources() {
    	return "stories" + File.separator + "simple-upgrades";
    }	

    protected List<String> storyPaths() {
        List<String> result = new ArrayList<String>();
        String storiesDirectoryWithinResources = getStoriesDirectoryWithinResources();
        URL resource = GeneralTest.class.getClassLoader().getResource(storiesDirectoryWithinResources);
        System.out.println(resource);
        try {
            File folder = new File(resource.toURI());
            if (folder.exists() && folder.canRead() && folder.isDirectory()) {
                File files[] = folder.listFiles();
                Arrays.sort(files);
                for (File file : files) {
                    result.add(file.getPath().substring(folder.getPath().lastIndexOf(storiesDirectoryWithinResources)));
                }
            }
        } catch (URISyntaxException e) {
            e.printStackTrace();
        }
        return result;
    }

　　 public static void main(String... args) {
		GeneralTest test = new GeneralTest();
		System.out.println(test.storyPaths());
　　 }
}

The output should be:

file:/home/username/workplace/JavaMavenPractice/target/classes/stories/simple-upgrades
[stories/simple-upgrades/retry-upgrade-file.story]