FileReader

• to read characters data or text data.
• Here, we can read character by character by character; not line by line.

Constructors

1. FileReader fr = new FileReader(String fileName);
2. FileReader fr = new FileReader(File f);

If no file is available, this will throw exception.

Methods

1. int read ()
2. Unicode value of character.
3. int read (char[] ch)
4. no of characters copied from file into array.
5. void close()

Examples

Text File

Hello my name is Arjun.

Read File By Looping

• Demo of a FileReader class.

  import java.io.FileReader;
  import java.io.IOException;
  
  
  class FileReaderDemo{
  
      // Method : int read()
      public static void main(String[] args){
          try{
              FileReader fr  = new FileReader("myText.txt");
              int i = fr.read();
              while(i != -1){ // Denotes no character
                  System.out.print((char)i); // Type-hinting
                  i = fr.read();
              }
              fr.close();
          }catch(IOException error){
              error.printStackTrace();
          }
      }   
  }
  

Read File With Character Array

• Demo of a FileReader class using a array.

  import java.io.*;
  
  class FileReaderDemo{
      public static void main(String[] args){
          try{
              // Method : int read(char[] ch)
              File f = new File("myText.txt");
              // Dynamically allocating the size of the array according to the text length inside file.
              char[] ch = new char[(int)f.length()];
              FileReader fr = new FileReader(f);
              fr.read(ch);
              // Assigns each character into another character variable.
              for(char ch1:ch){
                  System.out.print(ch1);
              }
              fr.close();
          }catch(IOException error){
              error.printStackTrace();
          }
      }
  }