java21.IO操作------FileReader与FileWriter

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

public class FileReaderWriter {

public static void main(String[] args) {
try {
FileReader fr = new FileReader("java.txt");
BufferedReader br = new BufferedReader(fr);

FileWriter fw = new FileWriter("java_new.txt");
BufferedWriter bw = new BufferedWriter(fw);

String line;
while ((line = br.readLine()) != null) {
bw.write(line + "\n");
}
bw.flush();
bw.close();
fw.close();
br.close();
fr.close();
System.out.println("done");
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}

}