How to get a file’s size in bytes ?

Problem & Solution

This example shows how to get a file’s size in bytes by using file.exists() and file.length() method of File class.

JAVA Program

import java.io.File;

public class Main {
   public static long getFileSize(String filename) {
      File file = new File(filename);
      if (!file.exists() || !file.isFile()) {
         System.out.println("File doesn\'t exist");
         return -1;
      }
      return file.length();
   }
   public static void main(String[] args) {
      long size = getFileSize("c:/java.txt");
      System.out.println("Filesize in bytes: " + size);
   }
}

Output

The above code sample will produce the following result.To test this example, first create a text file ‘java.txt’ in ‘C’ drive.The size may vary depending upon the size of the file.

File size in bytes: 480