Recursively find all text files in directory

Question

I am trying to get the names of all of the text files in a directory. If the directory has subdirectories then I also want to get any text files in those as well. I am not s

Answer 1

The answer is in the tags of your question. Use recursion. Recursion consists in having a method call itself.

In this case, the method should print all the text files directly under a given directory, and call itself for every subdirectory of the directory.

Answer 2

This is a recursive problem

public void find_files(File root)
{
    File[] files = root.listFiles(); 
    for (File file : files) {
        if (file.isFile()) {
            ...
        } else if (file.isDirectory()) {
            find_files(file);
        }
    }
}

Answer 3

using the java.nio.file capabilites of java 7. I implemented similiar func. and added some test.

Benchmarks when searching for .txt on my PC

            "c:/"  "c:/windows"
file.io   36272ms       14082ms
file.nio   7167ms        2987ms  

Read more in the javadoc, it's quite powerfull API

java.nio.file.filevisitor javadoc

public static void main(String[] args) {
    long starttime = System.currentTimeMillis();
    try {
        Path startPath = Paths.get("c:/");
        Files.walkFileTree(startPath, new SimpleFileVisitor<Path>() {
            @Override
            public FileVisitResult preVisitDirectory(Path dir,
                    BasicFileAttributes attrs) {
                System.out.println("Dir: " + dir.toString());
                return FileVisitResult.CONTINUE;
            }

            @Override
            public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) {
                if (file.toString().endsWith(".txt")){
                    System.out.println(file.toString());    
                }
                return FileVisitResult.CONTINUE;
            }

            @Override
            public FileVisitResult visitFileFailed(Path file, IOException e) {
                return FileVisitResult.CONTINUE;
            }
        });
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    long completetime = System.currentTimeMillis() - starttime;
    System.out.println("totaltime=" + completetime);

}