How to read a file in java with example program

We can read java file using buffered reader class in java

We need to import java.io.BufferedReader in order to read java text file.

Create object of java.io.BufferedReader class by passing new FileReader("C:\\Sample.txt") object to the constructor.

In order to read line by line call readLine() method of BufferedReader class which returns current line. Initially first line of java text file

 Program #1: Write a java program to read a file line by line using BufferedReader class 

package com.instanceofjava.javareadfile;

import java.io.BufferedReader;

import java.io.FileReader;

import java.io.IOException;

public class ReadFileBufferedReader {

 /**

  * 

  * @category: How to read java read file line by line using buffered reader

  */

public static void main(String[] args) {

  BufferedReader breader = null;

 try {

 String CurrentLine;

 breader = new BufferedReader(new FileReader("E://Sample.txt"));

 while ((CurrentLine = breader.readLine()) != null) {

    System.out.println(CurrentLine);

 }

} catch (IOException e) {

   e.printStackTrace();

} finally {

    try {

 if (breader != null)

     breader.close();

     } catch (IOException ex) {

    ex.printStackTrace();

     }

}

}

}

 Output:

  

Java open and read file

Read file line by line in java

Example java program to read a file line by line

java read file line by line example

Java example program to print message without using System.out.println()

Is it possible to print message without using system.out.println?




Yes its possible to print message without using System.out.println("");

System.out.write("www.corejavawithselenium.blogspot.in\n".getBytes());
 System.out.format("%s", "www.java.com \n")
 PrintStream myout =  new PrintStream(new FileOutputStream(FileDescriptor.out));
   myout.print("www.corejavawithselenium.blogspot.in \n");
System.err.print("This is custom error message");
System.console().writer().println("Hai");

1.System.out.write(Byte [] arg0);

System.out.write(Byte [] arg0) method The java.io.FilterOutputStream.write(byte[] b) method writes b.length bytes to this output stream.

package com.instanceofjava;

public class PrintMessage {

public static void main(String[] args) throws IOException{

       System.out.write("Hello World".getBytes());
}
}

Output:

Hello World

2. PrintStream  java.io.PrintStream.format(String arg0, Object... arg1)

System.out.format("format",Object obj) by using this method we can format the text and print

package com.instanceofjava;

public class PrintMessage {

public static void main(String[] args){

        System.out.format("%s", "James");
}

}

Output:

James

3. FileDescriptor:

Create PrintStream object by passing FileOutputStream(FileDescriptor.out) object as an argument to the constructor
package com.instanceofjava;

public class PrintMessage {

public static void main(String[] args){

       PrintStream myout =  new PrintStream(new FileOutputStream(FileDescriptor.out));
          myout.print("i love Java");
}
}

Output:

i love java


4. System.err.print(""):

We can use System.err.print("") method to print the message actually its used to print error message
package com.instanceofjava;

public static void main(String[] args){

       System.err.print("This is custom error message");
}
}

Output:

This is custom error message


5.System.console().writer().println("");

System.console() returns null if your application is not run in a terminal System.console() provides methods for reading password without echoing characters

package com.instanceofjava;

public static void main(String[] args){

       System.err.print("This is custom error message");
}
}

Output:

This is custom error message Exception in thread "main" java.lang.NullPointerException
    at PrintMessage.main(PrintMessage.java:24)