丁老师布置的作业，玛一段7-6的源程序（Bwriter.java)

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("file1.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();
}
}