How to get all files with certain extension in a folder in java

In this post, we will see how to list all files with certain extension in a folder.
For example, you want to list all .jpg or .zip files in a folder.

We will use FilenameFilter interface to list the files in a folder, so we will create a inner class which will implement FilenameFilter interface and implement accept method. We need to pass created inner class to java.io.File ‘s list method to list all files with specific extension.

Java Program :

package org.arpit.java2blog;

import java.io.File;

import java.io.FilenameFilter;

public class GetAllFilesWithCertainExtMain {

* @author Arpit Mandliya

public static void main(String[] args) {

GetAllFilesWithCertainExtMain main=new GetAllFilesWithCertainExtMain();

System.out.println("Finding .zip files in the folder /Users/Arpit/Desktop/Blog");

System.out.println("-----------------");

// Read the file

File folder=new File("/Users/Arpit/Desktop/Blog");

main.getAllFilesWithCertainExtension(folder,"zip");

System.out.println("-----------------");

}

public void getAllFilesWithCertainExtension(File folder,String filterExt)

{

MyExtFilter extFilter=new MyExtFilter(filterExt);

if(!folder.isDirectory())

{

System.out.println("Not a folder");

}

else

{

// list out all the file name and filter by the extension

String[] list = folder.list(extFilter);

if (list.length == 0) {

System.out.println("no files end with : " + filterExt);

return;

}

for (int i = 0; i < list.length; i++) {

System.out.println("File :"+list[i]);

}

// inner class, generic extension filter

public class MyExtFilter implements FilenameFilter {

private String ext;

public MyExtFilter(String ext) {

this.ext = ext;

}

public boolean accept(File dir, String name) {

return (name.endsWith(ext));

}

When I ran above program, I got following output:

Finding .zip files in the folder /Users/Arpit/Desktop/Blog

-----------------

File :sampleFile1.zip

File :sampleFile2.zip

File :sampleFile3.zip

File :Spring3-Quartz-Example.zip

File :SpringQuartzIntegrationExample.zip

-----------------

So we have found all .zip file in folder “/Users/Arpit/Desktop/Blog”

Author

Java File IO

27 December

How to get current working directory in java

Learn about how to get current working directory in java using different ways

Java File IO

08 August

Difference between Scanner and BufferReader in java

Table of ContentsIntroductionScannerBufferedReaderDifference between Scanner and BufferedReader In this post, we will see difference between Scanner and BufferReader in java. Java has two classes that have been used for reading files for a very long time. These two classes are Scanner and BufferedReader. In this post, we are going to find major differences and similarities […]

Java File IO

29 March

Read UTF-8 Encoded Data in java

Table of ContentsUsing Files’s newBufferedReader()Using BufferedReaderUsing DataInputStream’s readUTF() method In this post, we will see how to read UTF-8 Encoded Data. Sometimes, we have to deal with UTF-8 Encoded Data in our application. It may be due localization or may be processing data from user input. There are multiple ways to read UTF-8 Encoded Data […]

Java File IO

29 March

Write UTF-8 Encoded Data in java

Table of ContentsUsing Files’s newBufferWriter()Using BufferedWriterUsing DataOutputStream’s writeUTF() method In this post, we will see how to write UTF-8 Encoded Data. Sometimes, we have to deal with UTF-8 Encoded Data in our application. It may be due localization or may be processing data from user input. We will use Hindi language sentences to write in […]

Java File IO

15 March

Java read file line by line

Table of ContentsJava 8 StreamsUsing BufferReaderUsing ScannerUsing FilesUsing RandomAccessFileUsing Apache Commons In this post, we will see different ways to read file line by line in java. Sometimes, we need to read file line by line to a String, and process it. Here are different ways to read file line by line in java. Java […]

Core java Java File IO

06 February

Java FileWriter Example

Table of ContentsConstructorsMethodsExampleCode:Output: The FileWriter class of java.io package makes writing to files in Java as easy as A-B-C. The FileWriter class writes to files as a stream of characters instead of bytes(as in FileOutputStream). Like its input-oriented counterpart FileReader, the FileWriter class is intended for writing “text” based files one character at a time. […]