How to get list of all files/folders from a folder in Java?


The class named File of the java.io package represents a file or directory (path names) in the system. This class provides various methods to perform various operations on files/directories.

To get the list of all the existing files in a directory this class provides the files class provides list() (returns names) and ListFiles (returns File objects) with different variants.

The List() method

This method returns a String array which contains the names of all the files and directories in the path represented by the current (File) object.

Using this method, you can just print the names of the files and directories.

Example

The following Java program lists the names of all the files and directories in the path D:\\ExampleDirectory.

import java.io.File;
import java.io.IOException;
public class ListOfFiles {
   public static void main(String args[]) throws IOException {
      //Creating a File object for directory
      File directoryPath = new File("D:\\ExampleDirectory");
      //List of all files and directories
      String contents[] = directoryPath.list();
      System.out.println("List of files and directories in the specified directory:");
      for(int i=0; i<contents.length; i++) {
         System.out.println(contents[i]);
      }
   }
}

Output

List of files and directories in the specified directory:
SampleDirectory1
SampleDirectory2
SampleFile1.txt
SampleFile2.txt
SapmleFile3.txt

The ListFiles() method

This method returns an array holding the objects (abstract paths) of all the files (and directories) in the path represented by the current (File) object.

Since this method returns the objects of each file/directory in a folder. Using it you can access the properties of the files/directories such as size, path etc.

Example

The following Java program prints the name, path and, size of all the files in the path D:\\ExampleDirectory.

import java.io.File;
import java.io.IOException;
public class ListOfFiles {
   public static void main(String args[]) throws IOException {
      //Creating a File object for directory
      File directoryPath = new File("D:\\ExampleDirectory");
      //List of all files and directories
      File filesList[] = directoryPath.listFiles();
      System.out.println("List of files and directories in the specified directory:");
      for(File file : filesList) {
         System.out.println("File name: "+file.getName());
         System.out.println("File path: "+file.getAbsolutePath());
         System.out.println("Size :"+file.getTotalSpace());
         System.out.println(" ");
      }
   }
}

Output

List of files and directories in the specified directory:
File name: SampleDirectory1
File path: D:\ExampleDirectory\SampleDirectory1
Size :262538260480

File name: SampleDirectory2
File path: D:\ExampleDirectory\SampleDirectory2
Size :262538260480

File name: SampleFile1.txt
File path: D:\ExampleDirectory\SampleFile1.txt
Size :262538260480

File name: SampleFile2.txt
File path: D:\ExampleDirectory\SampleFile2.txt
Size :262538260480

File name: SapmleFile3.txt
File path: D:\ExampleDirectory\SapmleFile3.txt
Size :262538260480

The List(FilenameFilter filter) method

As suggested in its signature, this method accepts a FilenameFilter object and returns a String array containing the names of all the files and directories in the path represented by the current (File) object. But the retuned array contains the filenames which are filtered based on the specified filter.

Using this method, you can get the filtered names of the files and directories in a particular folder.

Example

The following Java program prints the names of the text files in the path D:\\ExampleDirectory.

import java.io.File;
import java.io.FilenameFilter;
import java.io.IOException;
public class ListOfFiles {
   public static void main(String args[]) throws IOException {
      //Creating a File object for directory
      File directoryPath = new File("D:\\ExampleDirectory");
      FilenameFilter textFilefilter = new FilenameFilter(){
         public boolean accept(File dir, String name) {
            String lowercaseName = name.toLowerCase();
            if (lowercaseName.endsWith(".txt")) {
               return true;
            } else {
               return false;
            }
         }
      };
      //List of all the text files
      String filesList[] = directoryPath.list(textFilefilter);
      System.out.println("List of the text files in the specified directory:");
      for(String fileName : filesList) {
         System.out.println(fileName);
      }
   }
}

Output

List of the text files in the specified directory −

SampleFile1.txt
SampleFile2.txt
SapmleFile3.txt

The ListFiles(FilenameFilter filter) method

This method accepts a FilenameFilter object and returns a File array containing the objects of all the files and directories in the path represented by the current File object. But the retuned array contains the files (objects) which are filtered based on their name

Using this method, you can get the filtered file objects of the files and directories in a particular folder, according to their names.

Example

The following Java program prints the name, path and, size of all the text files in the path D:\\ExampleDirectory.

import java.io.File;
import java.io.FilenameFilter;
import java.io.IOException;
public class ListOfFiles {
   public static void main(String args[]) throws IOException {
      //Creating a File object for directory
      File directoryPath = new File("D:\\ExampleDirectory");
      FilenameFilter textFilefilter = new FilenameFilter(){
         public boolean accept(File dir, String name) {
            String lowercaseName = name.toLowerCase();
            if (lowercaseName.endsWith(".txt")) {
               return true;
            } else {
               return false;
            }
         }
      };
      //List of all the text files
      File filesList[] = directoryPath.listFiles(textFilefilter);
      System.out.println("List of the text files in the specified directory:");
      for(File file : filesList) {
         System.out.println("File name: "+file.getName());
         System.out.println("File path: "+file.getAbsolutePath());
         System.out.println("Size :"+file.getTotalSpace());
         System.out.println(" ");
      }
   }
}

Output

List of the text files in the specified directory:
File name: SampleFile1.txt
File path: D:\ExampleDirectory\SampleFile1.txt
Size :262538260480

File name: SampleFile2.txt
File path: D:\ExampleDirectory\SampleFile2.txt
Size :262538260480

File name: SapmleFile3.txt
File path: D:\ExampleDirectory\SapmleFile3.txt
Size :262538260480

The ListFiles(FileFilter filter) method

This method accepts a FileFilter object and returns a File array containing the (File) objects of all the files and directories in the path represented by the current File object. But the retuned array contains the files (objects) which are filtered based on the property of the file.

Using this method, you can get the filtered file objects of the files and directories in a particular folder based on the size, path, type (file or, directory) etc…

Example

The following Java program prints the name, path and, size of all the files (not folders) in the path D:\\ExampleDirectory.

import java.io.File;
import java.io.FileFilter;
import java.io.IOException;
public class ListOfFiles {
   public static void main(String args[]) throws IOException {
      //Creating a File object for directory
      File directoryPath = new File("D:\\ExampleDirectory");
      FileFilter textFilefilter = new FileFilter(){
         public boolean accept(File file) {
            boolean isFile = file.isFile();
            if (isFile) {
               return true;
            } else {
               return false;
            }
         }
      };
      //List of all the text files
      File filesList[] = directoryPath.listFiles(textFilefilter);
      System.out.println("List of the text files in the specified directory:");
      for(File file : filesList) {
         System.out.println("File name: "+file.getName());
         System.out.println("File path: "+file.getAbsolutePath());
         System.out.println("Size :"+file.getTotalSpace());
         System.out.println(" ");
      }
   }
}

Output

List of the text files in the specified directory:
File name: cassandra_logo.jpg
File path: D:\ExampleDirectory\cassandra_logo.jpg
Size :262538260480

File name: cat.jpg
File path: D:\ExampleDirectory\cat.jpg
Size :262538260480

File name: coffeescript_logo.jpg
File path: D:\ExampleDirectory\coffeescript_logo.jpg
Size :262538260480

File name: javafx_logo.jpg
File path: D:\ExampleDirectory\javafx_logo.jpg
Size :262538260480

File name: SampleFile1.txt
File path: D:\ExampleDirectory\SampleFile1.txt
Size :262538260480

File name: SampleFile2.txt
File path: D:\ExampleDirectory\SampleFile2.txt
Size :262538260480

File name: SapmleFile3.txt
File path: D:\ExampleDirectory\SapmleFile3.txt
Size :262538260480
raja
Published on 02-Aug-2019 11:01:52
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