Java/File Input Output/LineNumberReader

Convert lines into the canonical format, that is, terminate lines with the CRLF sequence.

   <source lang="java">

import java.io.FilterOutputStream; import java.io.IOException; import java.io.OutputStream; /**

* Convert lines into the canonical format, that is, terminate lines with the
* CRLF sequence.
* 
* @author John Mani
*/

public class CRLFOutputStream extends FilterOutputStream {

 protected int lastb = -1;
 protected boolean atBOL = true; // at beginning of line?
 private static final byte[] newline = { (byte) "\r", (byte) "\n" };
 public CRLFOutputStream(OutputStream os) {
   super(os);
 }
 public void write(int b) throws IOException {
   if (b == "\r") {
     writeln();
   } else if (b == "\n") {
     if (lastb != "\r")
       writeln();
   } else {
     out.write(b);
     atBOL = false;
   }
   lastb = b;
 }
 public void write(byte b[]) throws IOException {
   write(b, 0, b.length);
 }
 public void write(byte b[], int off, int len) throws IOException {
   int start = off;
   len += off;
   for (int i = start; i < len; i++) {
     if (b[i] == "\r") {
       out.write(b, start, i - start);
       writeln();
       start = i + 1;
     } else if (b[i] == "\n") {
       if (lastb != "\r") {
         out.write(b, start, i - start);
         writeln();
       }
       start = i + 1;
     }
     lastb = b[i];
   }
   if ((len - start) > 0) {
     out.write(b, start, len - start);
     atBOL = false;
   }
 }
 /*
  * Just write out a new line, something similar to out.println()
  */
 public void writeln() throws IOException {
   out.write(newline);
   atBOL = true;
 }

}

 </source>
   
  
 
  

Create LineNumberReader from FileReader

   <source lang="java">
   

import java.io.FileReader; import java.io.LineNumberReader; class LineViewer {

 public static void main(String[] args) throws Exception {
   LineNumberReader lnr = null;
   FileReader fr = new FileReader(args[0]);
   lnr = new LineNumberReader(fr);
   String s;
   while ((s = lnr.readLine()) != null)
     System.out.println(lnr.getLineNumber() + ": " + s);
 }

}

 </source>
   
  
 
  

Line Number IO

   <source lang="java">
    

import java.io.FileReader; import java.io.IOException; import java.io.LineNumberReader; public class LineNumberIOApp {

 public static void main(String args[]) throws IOException {
   FileReader inFile = new FileReader("LineNumberIOApp.java");
   LineNumberReader inLines = new LineNumberReader(inFile);
   String inputLine;
   while ((inputLine = inLines.readLine()) != null) {
     System.out.println(inLines.getLineNumber() + ". " + inputLine);
   }
 }

}

 </source>
   
  
 
  

Split Lines

   <source lang="java">
   

import java.io.IOException; import java.io.LineNumberReader; import java.io.StringReader; import java.util.ArrayList; import java.util.List; /*

*  soapUI, copyright (C) 2004-2009 eviware.ru 
*
*  soapUI is free software; you can redistribute it and/or modify it under the 
*  terms of version 2.1 of the GNU Lesser General Public License as published by 
*  the Free Software Foundation.
*
*  soapUI is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without 
*  even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
*  See the GNU Lesser General Public License for more details at gnu.org.
*/

public class Utils {

 public static final String NEWLINE = System.getProperty( "line.separator" );

 public static boolean isNullOrEmpty( String str )
 {
   return str == null || str.length() == 0 || str.trim().length() == 0;
 }

 public static List<String> splitLines( String string )
 {
   try
   {
     ArrayList<String> list = new ArrayList<String>();
     LineNumberReader reader = new LineNumberReader( new StringReader( string ) );
     String s;
     while( ( s = reader.readLine() ) != null )
     {
       list.add( s );
     }
     return list;
   }
   catch( IOException e )
   {
     // I don"t think this can really happen with a StringReader.
     throw new RuntimeException( e );
   }
 }

}

 </source>
   
  
 
  

Use LineNumberReader class to read file

   <source lang="java">
   

import java.io.File; import java.io.FileReader; import java.io.LineNumberReader; public class Main {

 public static void main(String[] args) throws Exception {
   File file = new File("data.csv");
   FileReader fr = new FileReader(file);
   LineNumberReader lnr = new LineNumberReader(fr);
   // lnr.setLineNumber(400);
   String line = "";
   while ((line = lnr.readLine()) != null) {
     System.out.println("Line Number " + lnr.getLineNumber() + ": " + line);
   }
   fr.close();
   lnr.close();
 }

}

 </source>
   
  
 
  

Using the LineNumberReader to read a text file line by line

   <source lang="java">
   

import java.io.FileReader; import java.io.LineNumberReader; public class Main {

 public static void main(String[] args) throws Exception {
   LineNumberReader r = new LineNumberReader(new FileReader("yourFile.txt"));
   String line = null;
   while ((line = r.readLine()) != null) {
     System.out.println(r.getLineNumber() + ": " + line);
   }
   r.close();
 }

}

 </source>