How to List Files of a Certain Type using a FilenameFilter

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This example shows how to list files with a certain extension using the java.io.FilenameFilter interface.
To list files of a certain type (with a certain extension), create an instance of type FilenameFilter and override its accept method.
The accept method of the FilenameFilter takes a File object and a filename as parameters. Use the filename parameter to check the extension and if it's a file that you want to include, return true, otherwise false.

import java.io.File;
import java.io.FilenameFilter;

public class FileUtil {

  public void listFiles(String dir) {

    File directory = new File(dir);

    if (!directory.isDirectory()) {
      System.out.println("No directory provided");
      return;
    }

    //create a FilenameFilter and override its accept-method
    FilenameFilter filefilter = new FilenameFilter() {

      public boolean accept(File dir, String name) {
        //if the file extension is .txt return true, else false
        return name.endsWith(".txt");
      }
    };

    String[] filenames = directory.list(filefilter);

    for (String name : filenames) {
      System.out.println(name);
    }
  }

  public static void main(String[] args) {
    FileUtil fileutil = new FileUtil();
    fileutil.listFiles("C:\\\\temp");
  }
}

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