实践作业：从键盘输入一系列字符串，写入到某磁盘文件中

import java.io.*;public class Bwriter {public static void main(String[] args) throws Exception{InputStreamReader i = new InputStreamReader(System.in);BufferedReader b = new BufferedReader(i);FileWriter f = new FileWriter("file.txt");BufferedWriter w = new BufferedWriter(f);String s;while(true){System.out.print("input a string:");System.out.flush();s = b.readLine();if(s.length() == 0)break;w.write(s);w.newLine();}w.close();}}