How to search a directory with file extensions in Java?

Following example prints the files in a directory based on the extensions −

Example

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.stream.Stream;
public class Demo {
   public static void main(String[] args) throws IOException {
      Stream<Path> path = Files.walk(Paths.get("D:\\ExampleDirectory"));
      System.out.println("List of PDF files:");
      path = path.filter(var -> var.toString().endsWith(".pdf"));
      path.forEach(System.out::println);      
      path = Files.walk(Paths.get("D:\\ExampleDirectory"));
      System.out.println("List of JPG files:");
      path = path.filter(var -> var.toString().endsWith(".jpg"));
      path.forEach(System.out::println);    
      path = Files.walk(Paths.get("D:\\ExampleDirectory"));
      System.out.println("List of text files:");
      path = path.filter(var -> var.toString().endsWith(".txt"));
      path.forEach(System.out::println);      
      path = Files.walk(Paths.get("D:\\ExampleDirectory"));
      System.out.println("List of word files:");
      path = path.filter(var -> var.toString().endsWith(".docx"));
      path.forEach(System.out::println);      
    }
}

Output

List of PDF files:
D:\ExampleDirectory\demo1.pdf
D:\ExampleDirectory\demo2.pdf
List of JPG files:
D:\ExampleDirectory\sample_jpeg1.jpg
D:\ExampleDirectory\sample_jpeg2.jpg
List of text files:
D:\ExampleDirectory\sample1.txt
D:\ExampleDirectory\sample2.txt
D:\ExampleDirectory\sample3.txt
List of word files:
D:\ExampleDirectory\test1.docx
D:\ExampleDirectory\test2.docx

Following example prints the names of the PDF files in a directory based on the extensions −

Example

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

Output

List of the jpeg files in the specified directory:
demo1.pdf
demo2.pdf