Java program to traverse all files of a directory/folder

In this java program, we are going to learn how to access and traverse all files of a directory/folder? Here, we are traversing all files of a given directory.
Submitted by IncludeHelp, on December 05, 2017

Given a directory (folder) and we have to traverse its all files using java program.

Example:

Input:
Enter path: 'E:\Java'
(Java folder in 'E' drive)

Output:
About to traverse the directory: JAVA
   About to traverse the directory: 1 Nov
      Visiting file:ChristmasTree.java
      Visiting file:Find Files in Zip File.docx      
   Finished with the directory: 1 Nov
   About to traverse the directory: 2 Nov
      Visiting file:Combine Path.docx
      Visiting file:CombinePath.java
   Finished with the directory: 2 Nov
   About to traverse the directory: 3 Nov
      Visiting file:Check absolute path.docx
      Visiting file:CheckAbsolutePath.java
   Finished with the directory: 2 Nov

Program to traverse all files from a directory in java

import java.io.IOException;
import java.nio.file.*;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.Scanner;

public class TraverseFileSystem {
  public static void main(String[] args) {
    try {
      // create object of scanner.
      Scanner KB = new Scanner(System.in);

      // enter path here.
      System.out.print("Enter path here : ");
      String A = KB.next();
      Path path = Paths.get(A);
      ListFiles listFiles = new ListFiles();
      Files.walkFileTree(path, listFiles);
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
}

class ListFiles extends SimpleFileVisitor < Path > {
  private final int indentionAmount = 3;
  private int indentionLevel;

  public ListFiles() {
    indentionLevel = 0;
  }

  private void indent() {
    for (int i = 0; i < indentionLevel; i++) {
      System.out.print(' ');
    }
  }

  public FileVisitResult visitFile(Path file, BasicFileAttributes attributes) {
    indent();
    System.out.println("Visiting file:" + file.getFileName());
    return FileVisitResult.CONTINUE;
  }

  public FileVisitResult postVisitDirectory(Path directory, IOException e) throws IOException {
    indentionLevel = indentionAmount;
    indent();
    System.out.println("Finished with the directory: " + directory.getFileName());
    return FileVisitResult.CONTINUE;
  }

  public FileVisitResult preVisitDirectory(Path directory, BasicFileAttributes attributes) throws IOException {
    indent();
    System.out.println("About to traverse the directory: " + directory.getFileName());
    indentionLevel += indentionAmount;
    return FileVisitResult.CONTINUE;
  }

  public FileVisitResult visitFileFailed(Path file, IOException exc) throws IOException {
    System.out.println("A file traversal error ocurred");
    return super.visitFileFailed(file, exc);
  }
}

Output

Enter path here : E:/JAVA
About to traverse the directory: JAVA
   About to traverse the directory: 1 Nov
      Visiting file:ChristmasTree.java
      Visiting file:Find Files in Zip File.docx      
   Finished with the directory: 1 Nov
   About to traverse the directory: 2 Nov
      Visiting file:Combine Path.docx
      Visiting file:CombinePath.java
   Finished with the directory: 2 Nov
   About to traverse the directory: 3 Nov
      Visiting file:Check absolute path.docx
      Visiting file:CheckAbsolutePath.java
   Finished with the directory: 2 Nov