CS1103 Exercise Unit 6 - List all files in a directory and all its subdirectories recursively

Questions

Please write a program to list all files in a directory and all its subdirectories, and this program should ask the user to type in a directory name; if the name entered by the user is not a directory, the program ends with an error message printed out.

1. Codes

import java.io.File;
import java.util.Scanner;

/**
 * This program lists all the files in a directory and all its subdirectories.
 * The user is asked to type in a directory name.
 * If the name entered by the user is not a directory, a message is printed and the program ends.
 */
public class DirectoryList {
    public static void main(String[] args) {
        String directoryName;  // Directory name entered by the user.
        File directory;        // File object referring to the directory.
        String[] files;        // Array of file names in the directory.
        Scanner scanner;       // For reading a line of input from the user.

        scanner = new Scanner(System.in);  // scanner reads from standard input.

        System.out.println("--------->Enter a directory name: ");
        directoryName = scanner.nextLine().trim();
        directory = new File(directoryName);

        if (directory.isDirectory() == false) {
            if (directory.exists() == false)
                System.out.println("There is no such directory!");
            else
                System.out.println("That file is not a directory.");
        } else {
            System.out.println("\n--------->The content of the directory:");
            listDirectoriesRecursively(directory, "");  // List the directory recursively
        }
    }

    /**
     * If the content is a file, print it with indentation.
     * Otherwise, traverse directories recursively
     *
     * @param directory
     * @param indentation
     */
    private static void listDirectoriesRecursively(File directory, String indentation) {
        System.out.println(indentation + directory.getName() + ":"); // Print the directory name
        indentation += "   ";  // Increase the indentation for listing the contents.

        String[] content = directory.list(); // Get the content of the directory

        //If the content is a file, print it with indentation. Otherwise, traverse directories recursively
        for (String name : content) {
            File file = new File(directory, name);
            if (file.isDirectory())
                listDirectoriesRecursively(file, indentation); // traverse directories recursively
            else
                System.out.println(indentation + name);
        }
    }
}

2. Outputs

--------->Enter a directory name: 
F:\3.UoPeople\2.My Learning Guide\6. CS11103 Programming 2\Course Materials

--------->The content of the directory:
Course Materials:
   Week 1:
      1. U1 L1 - Using NetBeans to Set Up A Simple Java Project.mp4
      1. U1 L2 - Introduction to Jave and the Java Virtual Machine .mp4
      1. U1 L3 - Variables, Datatypes, Expressions and Evaluation.mp4
   Week 2:
      JavaFX - VM.txt
   Week 3:
   Week 4:
      BuggySearchAndSort.java
      Code Unit 4-20220220.zip
      GeneticProgramming_generations.txt
      GeneticProgram_vs_RandomSearch.txt
   Week 5:
   Week 6:
      Code Unit 6-20220306:
         DirectoryList.java
         DrawTextItem.java
         DrawTextPanel.java
         SimpleFileChooser.java
         TextCollage.java

Process finished with exit code 0

​

---

This is the ending, thanks for reading.

---