Hi,

Reading big file in memory is not an efficient method. You have to read the file one line at at time and process.

Here is complete code in Java that reads a text file "data.txt" one line at a time. In this example we have just printed the content on the console, but in real business scenario you can write code to process one line at a time.

Example code of Scanner Class to Read Text file:

package net.roseindia;
import java.io.File;
import java.util.Scanner;

/**
 * In this example we are going to use Scanner class to read a text file
 * Web: https://www.roseindia.net
 */

public class ScannerReadTextFile {

    public static void main(String[] args) {
        String fileName = "data.txt";
        try {
            File file = new File(fileName);

            Scanner input = new Scanner(file);
            while (input.hasNextLine()) {
                String line = input.nextLine();
                System.out.println(line);
            }
            input.close();
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

}

Hope this helps you.

Thanks