Java FileReader Class

The FileReader class in Java is used to read data from a file in the form of characters. It is a character-oriented stream that makes it ideal for reading text files. If you want to read binary data (like images or videos), use FileInputStream instead.

• Character-Oriented Stream: Reads data as 16-bit Unicode characters.
• Convenient for Text Files: Automatically handles character encoding.
• Platform Independent: Works across all operating systems.

Declaration

The class declaration of FileReader is as follows:

public class FileReader extends InputStreamReader

FileReader is a subclass of InputStreamReader, which in turn extends Reader.

Example: Reading Data from a File Using FileReader

import java.io.*;

class GFG{
    
    public static void main(String[] args){
        
        try{
            
            // FileReader Class used
            FileReader fileReader = new FileReader("example.txt");

            System.out.println("Reading char by char : \n");
            int i;

            // Using read method
            while ((i = fileReader.read()) != -1) {
                System.out.print((char)i);
            }

            System.out.println("Reading using array : \n");
            char[] charArray = new char[10];

            // Using read method for to get character array
            fileReader.read(charArray);
            System.out.print(charArray);

            // Close method called
            fileReader.close();
            System.out.println("FileReader closed!");
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

Output:

Hierarchy of the FileReader class.

It inherits from InputStreamReader, which in turn extends Reader and ultimately Object.

Constructors of Java FileReader Class

The Constructors inside FileReader are shown in the table below.

1. FileReader(String fileName)

Creates a new FileReader object to read data from a file with the given name.

FileReader fr = new FileReader("example.txt");

2. FileReader(File file)

Creates a new FileReader object to read from the specified File object.

File file = new File("example.txt");
FileReader fr = new FileReader(file);

3. FileReader(FileDescriptor fdObj)

Creates a FileReader using the specified file descriptor. It is often used when working with low-level file handling.

FileDescriptor fd = FileDescriptor.in;
FileReader fr = new FileReader(fd);

Methods of Java FileReader Class

The methods under FileReader are shown in the table below.