Code source java

Bonjour,

je suis débutante en programmation java ,j'ai trouver un code pour ouvrir un fichier texte mais j'ai besoin de lire seulement des lignes de ce fichier comment faire ça?
mon code source est:

package todo;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.Scanner;


public class openfile {
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);
        BufferedReader br = null;
        String line;
        
        System.out.println("Please enter the file name to be read");
        
        try{
            br = new BufferedReader(new FileReader("C:\\Users\\Khaoula\\Desktop\\file to read\\" + scanner.next()));
            
        } catch (FileNotFoundException fnfex) {
            System.out.println(fnfex.getMessage() +"the file was not found");
            System.exit(0);
            
        }
        
        try {
            while((line = br.readLine()) !=null)
                System.out.println(line);
        } catch (IOException ioex) {
            System.out.println(ioex.getMessage() + "Error reading file");
        } finally{
            System.exit(0);
        
        
    }
    
}
}