请问这些空空要怎么填啊

import ____________________ ;
class Demo
{ public static void main(String args[]){ int i = 1;
try {
FileReader fis = new_____________(args[0]); BufferedReader reader = new BufferedReader( _____ );
String s ；
while((s=reader.readLine())!=)
{
System.out.println(" "+(i++)+":" + s) ; //显示行号和读到的数据 }
fis.close();
reader.close(); }
catch (IOException e)
{
System.out.println(e); }
catch (__________ e1)
{
System.out.println(“缺少命令行参数！”); } }}

import java.io.*;

FileReader fis = new FileReader(args[0]);
BufferedReader reader = new BufferedReader (fis);

catch(FileNotFoundException e1)