设置行号代码

import java.io.*;
class DemoBuffer
{
    public static void main(String[] args)throws Exception
    {
        FileReader file=new FileReader("abc.txt");
        LineNumberReader lnr=new LineNumberReader(file);
        String line=null;    
        while((line=lnr.readLine())!=null)
        {
            System.out.println(lnr.getLineNumber()+","+line);
        }
    }    
}