Lecture et écriture dans un fichier

Solution : 

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;

public class Exemple {
	
	public static void main(String[] args) {
		BufferedReader br = null;
		PrintWriter pw = null;
		try {
			br = new BufferedReader(new FileReader("file/entree.in"));
			pw = new PrintWriter(new FileWriter("file/sortie.out"));
			String st = null;
			while ((st = br.readLine()) != null)
				pw.println(st);
		} catch (FileNotFoundException e) {
			System.out.println("Fichier introuvable");
		} catch (IOException e) {
			System.out.println("Impossible de lire les données");
		} finally {
			try {
				if (br != null)
					br.close();
				if (pw != null)
					pw.close();
			} catch (IOException e) {
				System.out.println("Impossible de fermer l'un des fichiers");
			}
		}

	}

}