In Java 7, list files with "relative path"

Question

Given the below directory structure:

/dir1
/dir1/dir2
/dir1/dir2/file1
/dir1/dir2/file2
/dir1/dir2/dirA/file3

someFunction("dir2")

desired output:

dir2/file1
dir2/file2
dir2/dirA/file3

I am using FileUtils.listFiles and Paths and then String manipulation, but wondering if better way. Just seems convoluted.

The Unix command find dir2 is pretty spot on.

@ArvindKumarAvinash A List of Strings shown above, or Paths or Files. — PaulM, Jan 29 '20 at 20:53
Check if https://stackoverflow.com/questions/2056221/recursively-list-files-in-java answers your question. — Arvind Kumar Avinash, Jan 29 '20 at 20:55

score 2 · Accepted Answer · answered Jan 29 '20 at 20:55

2

You have a base directory and a Collection<File>. You can use Path.relativize to get the relative path from one to the other.

This example, given /dir1 and /dir1/foo/bar/baz, will result in foo/bar/baz without any fragile string operations:

import java.io.*;
import java.nio.file.*;

class Foo {
  public static void main(String[] args) throws Exception {
    Path base = Paths.get("/dir1");
    File f = new File("/dir1/foo/bar/baz");
    System.out.println(base.relativize(f.toPath()));
  }
}

answered Jan 29 '20 at 20:55

that other guy

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Solution using relativize method removes need for string manipulation and regex. – PaulM Jan 30 '20 at 14:21
1

What is the reason for mixing `File` and `Path`? – Holger Feb 24 '20 at 15:12

score 1 · Answer 2 · answered Jan 29 '20 at 21:48

Since you're using the Java 7 Path, you might as well use the Java 7 Files too.

static void someFunction(String dir) throws IOException {
    Files.walkFileTree(Paths.get(dir), new SimpleFileVisitor<Path>() {
        @Override
        public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
            System.out.println(file);
            return FileVisitResult.CONTINUE;
        }
    });
}

Test

someFunction("dir2");

Output (on Windows¹)

dir2\dirA\file3
dir2\file1
dir2\file2

^{1) On Linux, the paths would have forward slash instead of backslash.}

In Java 7, list files with "relative path"

2 Answers2