Java Program to List all Files in a Directory and Nested Sub-Directories
Last Updated :
26 Jan, 2022
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Prerequisites: File class
Given a main directory/folder, list all the files from it, and if this directory has other nested sub-directories, list files from them. It is pretty easy to observe a simple recursion pattern in the above problem.
Algorithm :
- Create a File object for the main directory.
- Get an array of files for the main directory.
- If array[i] is a file:
- Print out the file name.
- If array[i] is a directory :
- Print out directory name.
- Get array of files for current sub-directory.
- Repeat the step 3 and 4 with current sub-directory.
- Repeat the step 3 and 4 with next array[i].
Example 1:
Java
// Java program to print all files// in a folder(and sub-folders)import java.io.File;public class GFG { static void RecursivePrint(File[] arr, int index, int level) { // terminate condition if (index == arr.length) return; // tabs for internal levels for (int i = 0; i < level; i++) System.out.print("\t"); // for files if (arr[index].isFile()) System.out.println(arr[index].getName()); // for sub-directories else if (arr[index].isDirectory()) { System.out.println("[" + arr[index].getName() + "]"); // recursion for sub-directories RecursivePrint(arr[index].listFiles(), 0, level + 1); } // recursion for main directory RecursivePrint(arr, ++index, level); } // Driver Method public static void main(String[] args) { // Provide full path for directory(change // accordingly) String maindirpath = "C:\\Users\\Gaurav Miglani\\Desktop\\Test"; // File object File maindir = new File(maindirpath); if (maindir.exists() && maindir.isDirectory()) { // array for files and sub-directories // of directory pointed by maindir File arr[] = maindir.listFiles(); System.out.println( "**********************************************"); System.out.println( "Files from main directory : " + maindir); System.out.println( "**********************************************"); // Calling recursive method RecursivePrint(arr, 0, 0); } }} |
Output:
**********************************************
Files from main directory : C:\Users\Gaurav Miglani\Desktop\Test
**********************************************
Cormen.pdf
Extra-Items.pdf
XYZ.pdf
[Docs]
A.docx
B.doc
C.docx
ABC.pdf
JKL.pdf
[sheets]
XXX.csv
YYY.csv
results.pdf
[Resumes]
[Before2016]
Resume2015.doc
Resume2016.doc
[Before2014]
Resume2014.doc
Resume2017.doc
Resume2017.pdf
QA.doc
Testing.pdf
Example 2: Below is another recursive program. Here we use recursion only for nested sub-directories. For main directory files, we use foreach loop.
Java
// Recursive Java program to print all files// in a folder(and sub-folders)import java.io.File;public class GFG { static void RecursivePrint(File[] arr, int level) { // for-each loop for main directory files for (File f : arr) { // tabs for internal levels for (int i = 0; i < level; i++) System.out.print("\t"); if (f.isFile()) System.out.println(f.getName()); else if (f.isDirectory()) { System.out.println("[" + f.getName() + "]"); // recursion for sub-directories RecursivePrint(f.listFiles(), level + 1); } } } // Driver Method public static void main(String[] args) { // Provide full path for directory(change // accordingly) String maindirpath = "C:\\Users\\Gaurav Miglani\\Desktop\\Test"; // File object File maindir = new File(maindirpath); if (maindir.exists() && maindir.isDirectory()) { // array for files and sub-directories // of directory pointed by maindir File arr[] = maindir.listFiles(); System.out.println( "**********************************************"); System.out.println( "Files from main directory : " + maindir); System.out.println( "**********************************************"); // Calling recursive method RecursivePrint(arr, 0); } }} |
Output:
**********************************************
Files from main directory : C:\Users\Gaurav Miglani\Desktop\Test
**********************************************
Cormen.pdf
Extra-Items.pdf
XYZ.pdf
[Docs]
A.docx
B.doc
C.docx
ABC.pdf
JKL.pdf
[sheets]
XXX.csv
YYY.csv
results.pdf
[Resumes]
[Before2016]
Resume2015.doc
Resume2016.doc
[Before2014]
Resume2014.doc
Resume2017.doc
Resume2017.pdf
QA.doc
Testing.pdf
Example 3 –
Below is another iterative program to get all file name using Stack DS
Java
// Iterative Program to get all file names in Directory and// SubDirectoryimport java.io.*;class GFG { public static void main(String[] args) { // provide complete path for directory(to be changed // accordingly) String mainDir = "c:\\GFG\\example"; // File object File file = new File(mainDir); Stack<File> s = new Stack<>(); s.push(file); // initially stack is not empty System.out.println("Content of Directory " + mainDir + " is"); while (!s.empty()) { File tmpF = s.pop(); // check if it is a file or not if (tmpF.isFile()) { // print file name can code here according // to our need System.out.println(tmpF.getName()); } else if (tmpF.isDirectory()) { // It's an directory hence list and push all // files in stack File[] f = tmpF.listFiles(); for (File fpp : f) { s.push(fpp); } } // else if ends here } // stack is not empty loop ends here } // main function ends here} |
Output:
Content of Directory c:\GFG\example is example.txt testTwo.java testTwo.class test.java test.class test.java eg1.java eg1.class test.java test.class Students.java Students.class
NOTE: The above code won’t compile on online IDE to compile and execute it download in your local system.
