How can I read a large text file line by line using Java?

Question

I need to read a large text file of around 5-6 GB line by line using Java.

How can I do this quickly?

Answer 1

What you can do is scan the entire text using Scanner and go through the text line by line. Of course you should import the following:

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public static void readText throws FileNotFoundException {
    Scanner scan = new Scanner(new File("samplefilename.txt"));
    while(scan.hasNextLine()){
        String line = scan.nextLine();
        //Here you can manipulate the string the way you want
    }
}

Scanner basically scans all the text. The while loop is used to traverse through the entire text.

The .hasNextLine() function is a boolean that returns true if there are still more lines in the text. The .nextLine() function gives you an entire line as a String which you can then use the way you want. Try System.out.println(line) to print the text.

Side Note: .txt is the file type text.