Java - FileReader Class

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This class inherits from the InputStreamReader class. FileReader is used for reading streams of characters.

This class has several constructors to create required objects.

Following syntax creates a new FileReader, given the File to read from.

FileReader(File file) 

Following syntax creates a new FileReader, given the FileDescriptor to read from.

FileReader(FileDescriptor fd) 

Following syntax creates a new FileReader, given the name of the file to read from.

FileReader(String fileName) 

Once you have FileReader object in hand then there is a list of helper methods which can be used manipulate the files.

SNMethods with Description
1public int read() throws IOException
Reads a single character. Returns an int, which represents the character read.
2public int read(char [] c, int offset, int len)
Reads characters into an array. Returns the number of characters read.

Example:

Following is the example to demonstrate class:

import java.io.*;

public class FileRead{

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

      File file = new File("Hello1.txt");
      // creates the file
      file.createNewFile();
      // creates a FileWriter Object
      FileWriter writer = new FileWriter(file); 
      // Writes the content to the file
      writer.write("This\n is\n an\n example\n"); 
      writer.flush();
      writer.close();

      //Creates a FileReader Object
      FileReader fr = new FileReader(file); 
      char [] a = new char[50];
      fr.read(a); // reads the content to the array
      for(char c : a)
          System.out.print(c); //prints the characters one by one
      fr.close();
   }
}

This would produce the following result:

This
is
an
example



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