Programming Tutorials

FileReader and FileWriter example program in Java

By: Tamil Selvan in Java Tutorials on 2022-09-15  

The FileReader and FileWriter classes in Java are used for reading and writing character streams from and to files, respectively. Here is an example program that demonstrates how to use these classes:

import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class FileReaderWriterExample {
    public static void main(String[] args) {
        try {
            // Create a FileReader object to read from a file
            FileReader reader = new FileReader("input.txt");

            // Create a FileWriter object to write to a file
            FileWriter writer = new FileWriter("output.txt");

            int ch;
            // Read each character from the input file and write it to the output file
            while ((ch = reader.read()) != -1) {
                writer.write(ch);
            }

            // Close the input and output files
            reader.close();
            writer.close();

            System.out.println("File has been copied successfully!");
        } catch (IOException e) {
            System.out.println("An error occurred: " + e.getMessage());
            e.printStackTrace();
        }
    }
}

In this example program, we first create a FileReader object to read characters from an input file named "input.txt". Then, we create a FileWriter object to write characters to an output file named "output.txt". We then read each character from the input file and write it to the output file until the end of the input file is reached. Finally, we close both the input and output files.

Note that we are catching an IOException in case any errors occur while reading or writing the files. This is important to ensure that our program does not crash in case of any unexpected errors.