The listFiles() method is a part of File class.The function returns an array of Files denoting the files in a given abstract pathname if the path name is a directory else returns null. The function is an overloaded function. One of the function does not have any parameter, the second function takes FilenameFilter object as parameter, the third function takes FileFilter object as parameter
Function Signature:
public File[] listFiles() public File[] listFiles(FilenameFilter f) public File[] listFiles(FileFilter f)
Function Syntax:
file.listFiles() file.listFiles(filter)
Parameters: The function is a overloaded function
- One of the function does not have any parameter,
- The second function takes FilenameFilter object as a parameter,
- The third function takes FileFilter object as a parameter
Return value: The function returns a File array, or null value if the file object is a file.
Exception: This method throws Security Exception if the function is not allowed read access to the file
Below programs will illustrate the use of the listFiles() function
Example 1: We will try to find all the files and directories in a given directory
// Java program to demonstrate the// use of listFiles() function import java.io.*; public class solution { public static void main(String args[]) { // try-catch block to handle exceptions try { // Create a file object File f = new File("f:\\program"); // Get all the names of the files present // in the given directory File[] files = f.listFiles(); System.out.println("Files are:"); // Display the names of the files for (int i = 0; i < files.length; i++) { System.out.println(files[i].getName()); } } catch (Exception e) { System.err.println(e.getMessage()); } }} |
Output:
Files are: 1232.txt 1245.txt 5671.txt program1
Example 2: We will try to find all the files and directories in a given directory whose names start with “12”
// Java program to demonstrate the// use of listFiles() function import java.io.*; public class solution { public static void main(String args[]) { // try-catch block to handle exceptions try { // Create a file object File f = new File("f:\\program"); // Create a FilenameFilter FilenameFilter filter = new FilenameFilter() { public boolean accept(File f, String name) { return name.startsWith("12"); } }; // Get all the names of the files present // in the given directory // and whose names start with "12" File[] files = f.listFiles(filter); System.out.println("Files are:"); // Display the names of the files for (int i = 0; i < files.length; i++) { System.out.println(files[i].getName()); } } catch (Exception e) { System.err.println(e.getMessage()); } }} |
Output:
Files are: 1232.txt 1245.txt
Example 3: We will try to find all the files and directories in a given directory which are text files
// Java program to demonstrate the// use of listFiles() function import java.io.*; public class solution { public static void main(String args[]) { // try-catch block to handle exceptions try { // Create a file object File f = new File("f:\\program"); // Create a FileFilter FileFilter filter = new FileFilter() { public boolean accept(File f) { return f.getName().endsWith("txt"); } }; // Get all the names of the files present // in the given directory // which are text files File[] files = f.listFiles(filter); System.out.println("Files are:"); // Display the names of the files for (int i = 0; i < files.length; i++) { System.out.println(files[i].getName()); } } catch (Exception e) { System.err.println(e.getMessage()); } }} |
Output:
Files are: 1232.txt 1245.txt 5671.txt
The programs might not run in an online IDE. please use an offline IDE and set the Parent file of the file
