Installation and Configuration
Programming Methodology

Reading and Writing Files (File, FileReader, FileWriter)

In this exercise, you will learn how to perform file read and write operations in Java using the File, FileReader, and FileWriter classes. You will explore how to open, read, and write data to text files, allowing you to efficiently manage input and output in your Java applications. This exercise is essential for working with files in real-world programming projects.

Topic

File Handling and Advanced Exceptions

Java Exercise

In this exercise, you will create a Java program that demonstrates how to work with files using the File, FileReader, and FileWriter classes. First, you will create a text file and enter data into it using FileWriter. Then, you will open the file to read its contents using FileReader. This exercise will help you understand how to perform input/output (I/O) operations on text files in Java.

Instructions:

  1. Create a text file named example.txt using the FileWriter class.
  2. Write some data to the file using FileWriter.
  3. Read the contents of the file using the FileReader class.
  4. Print the contents of the file to the console to verify that the data was read correctly.

This exercise will help you understand basic file input/output operations in Java, providing you with the tools to manipulate data in files and improve the interactivity of your Java programs.


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

public class FileHandling {
    public static void main(String[] args) {
        // Create a text file and write to it
        try {
            File file = new File("example.txt");
            if (!file.exists()) {
                file.createNewFile();  // Create file if it doesn't exist
            }
            
            FileWriter writer = new FileWriter(file);
            writer.write("This is a sample file in Java.\nThis file contains multiple lines of text.");
            writer.close();  // Close the writer

            // Read the content of the file
            FileReader reader = new FileReader(file);
            int i;
            StringBuilder content = new StringBuilder();
            while ((i = reader.read()) != -1) {
                content.append((char) i);  // Append each character to StringBuilder
            }
            reader.close();  // Close the reader

            // Print the file content
            System.out.println("File content:");
            System.out.println(content.toString());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

 Output:

File Contents:
This is an example of a Java file.
This file contains several lines of text.

This program demonstrates how to work with files in Java using the File, FileReader, and FileWriter classes. First, a file named example.txt is created, written to using FileWriter, and then the contents are read using FileReader. When the program is run, the file contents are displayed in the console, providing an understanding of how to perform basic file input/output operations in Java.


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