JAVA EE: Java Tutorial : Java IO (Java File - How to Find and list out files with certain extension only-V1)

Tuesday, 15 November 2016

Java Tutorial : Java IO (Java File - How to Find and list out files with certain extension only-V1)

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https://www.youtube.com/watch?v=OcI3ogBQt-4&list=UUhwKlOVR041tngjerWxVccw

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Java Tutorial : Java IO (Java File - How to Find and list out files with certain extension only-V1)

work-dir.jpg

Java Tutorial : Java IO (Java File - How to Find and list out files with certain extension only-V1)

ExtensionFilter.java

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

/*
 * boolean accept(File dir, String name)
 * 
 * Parameters: 
 * ----------
 * 
 * dir - the directory in which the file was found. 
 * name - the name of the file.
 */
public class ExtensionFilter implements FilenameFilter
{

    private String fileExtension;

    public ExtensionFilter(String fileExtension)
    {
        this.fileExtension = fileExtension;
    }

    /*
     * Tests if a specified file should be included in a
     * file list.
     * 
     * Returns: true if and only if the name should be
     * included in the file list; false otherwise.
     */
    @Override
    public boolean accept(File dir, String name)
    {
        return (name.endsWith(fileExtension));
    }

}

FileDemo.java

import java.io.File;

/*
 * public String[] list(FilenameFilter filter)
 *
 * Parameters:
 * ----------
 *
 * filter - A filename filter
 *
 * How to use FilenameFilter to list out all files that
 * are end with “.txt” extension in folder “D:/work“. *
 */

public class FileDemo
{

    public static void main(String[] args)
    {
        FileDemo fileDemo = new FileDemo();
        fileDemo.listOutFiles("D:/work", ".txt");
    }

    public void listOutFiles(String dirName, String fileExtension)
    {
        File fileDir = new File(dirName);

        ExtensionFilter extFilter = new ExtensionFilter(fileExtension);

        /*
         * Returns an array of strings naming the files and
         * directories in the directory denoted by this
         * abstract pathname that satisfy the specified
         * filter.
         */
        String[] listOfFileNames = fileDir.list(extFilter);

        if (listOfFileNames.length == 0)
        {
            System.out.println("No files end with : " + fileExtension);
            return;
        }

        for (String fileName : listOfFileNames)
        {
            System.out.println(fileName);
        }

    }

}