JAVA读取txt同时对txt及进行修改

import java.io.*;
public class test{
    public static void main(String args[])throws IOException{
        int modifyline=1;//要修改的行
        BufferedReader in=new BufferedReader(new FileReader("src/1.txt"));
        PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("src/2.txt")));
        String line;
        int count=1;
        while((line=in.readLine())!=null){
                out.println(line.replace('c', 'f'));  //替换a成f
            count++;
        }
        in.close();
        out.close();
    }
}