代码如下：

public class MyWork {
    public static void main(String[] args) throws IOException{
        BufferedReader fr = new BufferedReader(new FileReader("myfile/abc.txt"));
        BufferedWriter fw = new BufferedWriter(new FileWriter("myfile/test.txt"));
        String line;
        while ((line = fr.readLine()) != null) {
            fw.write(line);
            fw.newLine();
            fw.flush();
        }
        fr.close();
        fw.close();

        //这一段是测试代码
        RandomAccessFile rf = new RandomAccessFile("myfile/abc.txt", "r");
        int len;
        while ((len = rf.read()) != -1) {
            System.out.print((char)len);
        }
        System.out.println();
        rf.seek(0);
        while ((len = rf.read()) != -1) {
            System.out.print((char)len);
        }
    }
}

备注：字符缓冲流有自己特有的方法，也可以用普通的read()和write()方法。