Example Program

The readLine() method reads a line of text from a character-oriented input stream, and puts it into a String object which it returns as a reference. If there is no more data in the file, it returns null.

import java.io.*;
class ReadTextFile
{
 public static void main ( String[] args ) 
 {
   String fileName = "reaper.txt" ;
   String line;

   try
   {      
     BufferedReader in = new BufferedReader( new FileReader( fileName  ) );
     line = in.readLine();
     while ( line != null )  // continue until end of file
     {
       System.out.println( line );
       line = in.readLine();
     }
     in.close();
   }
   catch ( IOException iox )
   {
     System.out.println("Problem reading " + fileName );
   }
 }
}

The file reaper.txt is opened for reading when the FileReader stream is constructed. If the file does not exist in the current directory, an IOException is thrown. Next, the program reads each line of the file and writes it to the monitor. When end-of-file is detected the program quits.

This is an extremely common programming pattern: reading and processing data until end-of-file. It would be worth while to play with this program. Create reaper.txt with a text editor if it does not already exist.