How to get a file from jar?

Question

I need a file filename.txt which is inside a jar file. How can I read the contents of the txt file using code? Are there any libraries available for working with *.jar files?

Answer 1

public class Test {
    public static void main(String[] args) {
        InputStream stream = Test.class.getResourceAsStream("/test.txt");
        Scanner s = new Scanner(stream);
        while (s.hasNext()) {
            System.out.println(s.next());
        }
    }
}

The jar needs to be on the classpath of the application.

This code will search for the file test.txt in the root of all jars.

If you need to specify a jar that isn't on the classpath, then the other suggestions might be more worthwhile.

Answer 2

If the jar is in the classpath, you can access a file in it using getClass().getClassLoader().getResourceAsStream(...). If the jar file is not in the classpath, then check out java.util.jar.JarFile.