Java Program to Read a File

This article covers a program in Java that reads a file, entered by user at run-time of the program.

Read a File Line by Line in Java

The question is, write a Java program to read a file, line by line using Scanner. The program given below is its answer:

import java.util.Scanner;
import java.io.*;

public class fresherearth
{
   public static void main(String[] args)
   {
      String myfile, myline;
      Scanner scan = new Scanner(System.in);
      
      System.out.print("Enter File Name: ");
      myfile = scan.nextLine();
      
      try
      {
         FileReader fileReader = new FileReader(myfile);
         BufferedReader bufread = new BufferedReader(fileReader);
         
         // reading the file, line by line
         while((myline = bufread.readLine()) != null)
            System.out.println(myline);
         
         bufread.close();
      }
      catch(IOException e)
      {
         System.out.println("Exception: " +e);
      }
   }
}

The snapshot given below shows the sample run of above program, with user input fresherearth.txt as name of file to read

In the above program, if you change the following block of code:

while((myline = bufread.readLine()) != null)
   System.out.println(myline);

with the block of code given below:

int line_no = 1;
while((myline = bufread.readLine()) != null)
{
   System.out.println("Line No." +line_no+ ": \"" +myline+ "\"");
   line_no++;
}

then the output will be:

java program to read a file line by line

The while loop, can also be replaced with for. Here is the for loop version of the same block, created using while:

int line_no = 1;
for(myline=bufread.readLine(); myline!=null; myline=bufread.readLine())
{
   System.out.println("Line No." +line_no+ ": \"" +myline+ "\"");
   line_no++;
}

The file fresherearth.txt is already available inside the current directory. The directory in which the above Java application's source code is saved.

Same Program in Other Languages

Java Online Test

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