How to find length of given file in Java?

Problem Description :

Write a program in Java that finds the length of given file.

Java program that finds the length of given file.

How to find the length of given file in Java?

Concept :

We need to use following method of File class that is present in java.io.* package.

public long length()

Java Program :

package com.javamultiplex.FileHandling; import java.io.File; import java.io.IOException; import java.util.Scanner; /** * * @author Rohit Agarwal * @category File Handling * @problem How to find length of given file in Java? * */ public class LengthFinder { public static void main(String[] args) throws IOException { Scanner input = null; try { input = new Scanner(System.in); System.out.println("Enter file name with extension : "); String fileName = input.nextLine(); if (isValidFileName(fileName)) { // File is present in current working directory. File file = new File(fileName); long length = file.length(); System.out.println("Length of file is : " + length + " bytes."); } else { System.out.println("File name is invalid."); } } finally { if (input != null) { input.close(); } } } private static boolean isValidFileName(String fileName) { //Regular expression for validating file name. String pattern = "^.+\\..+$"; boolean result = false; if (fileName.matches(pattern)) { result = true; } return result; } }

Output :

Output - How to find the length of given file in Java?

Demo of file length finder

References :

https://docs.oracle.com/javase/7/docs/api/java/io/File.html

https://docs.oracle.com/javase/7/docs/api/java/io/File.html#length()

https://en.wikipedia.org/wiki/Regular_expression

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Tags : File Handling, file length finder, if else, Scanner, String, File, Regular expression, length(), java.io.

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