Java.io.LineNumberReader.readLine() Method

Description

The java.io.LineNumberReader.readLine() method reads a line of text.

Declaration

Following is the declaration for java.io.LineNumberReader.readLine() method:

public String readLine()

Parameters

• NA

Return Value

The method returns a string containing the contents of the line, not including any line termination characters, or null if the end of the stream is reached.

Exception

• IOException -- if an I/O error occurs

Example

The following example shows the usage of java.io.LineNumberReader.readLine() method.

package com.tutorialspoint;

import java.io.FileReader;
import java.io.IOException;
import java.io.LineNumberReader;

public class LineNumberReaderDemo {
   public static void main(String[] args) throws IOException {
      
      FileReader fr = null;
      LineNumberReader lnr = null;
      String str;
      int i;
      
      try{
         // create new reader
         fr = new FileReader("C:/test.txt");
         lnr = new LineNumberReader(fr);
   
         // read lines till the end of the stream
         while((str=lnr.readLine())!=null)
         {
            i=lnr.getLineNumber();
            System.out.print("("+i+")");
                  
            // prints string
            System.out.println(str);
         }
      }catch(Exception e){
         
         // if any error occurs
         e.printStackTrace();
      }finally{
         
         // closes the stream and releases system resources
         if(fr!=null)
            fr.close();
         if(lnr!=null)
            lnr.close();
      }
   }
}

Assuming we have a text file c:/test.txt, which has the following content. This file will be used as an input for our example program:

ABCDE

Let us compile and run the above program, this will produce the following result:

(1)ABCDE
(2)FGHIJ
(3)KLMNO
(4)PQRST
(5)UVWXY
(6)z