Java I/O

Java Input/Output (I/O) refers to the process of reading data from and writing data to external sources such as files, streams, networks, and other devices. The Java I/O system provides classes and APIs to handle various I/O operations efficiently and effectively. Java’s I/O operations are categorized into two main types: byte-based I/O and character-based I/O.

Byte-Based I/O:
Byte-based I/O is used to handle raw binary data. It’s suitable for reading and writing non-text files, images, audio, video, and other binary data.

1. InputStream and OutputStream: The base classes for byte-based input and output operations. Common subclasses include FileInputStream, FileOutputStream, and ByteArrayInputStream.
2. DataInputStream and DataOutputStream: Wrappers around InputStream and OutputStream that allow you to read and write primitive data types (e.g., int, double) in binary format.
3. BufferedInputStream and BufferedOutputStream: Buffered versions of byte-based I/O classes, providing improved performance by reducing the number of actual I/O operations.

Character-Based I/O:
Character-based I/O is used for reading and writing text data, and it deals with characters rather than raw binary data.

1. Reader and Writer: The base classes for character-based input and output operations. Subclasses include FileReader, FileWriter, and StringReader.
2. BufferedReader and BufferedWriter: Buffered versions of character-based I/O classes, offering improved performance by reducing the number of I/O operations.
3. InputStreamReader and OutputStreamWriter: Classes that bridge byte-based and character-based I/O. They allow you to convert between byte streams and character streams using specified character encodings.

File I/O:
Java provides classes to read from and write to files.

import java.io.*;

public class FileIOExample {
    public static void main(String[] args) {
        try {
            // Writing to a file
            FileWriter writer = new FileWriter("output.txt");
            writer.write("Hello, Java I/O!");
            writer.close();

            // Reading from a file
            FileReader reader = new FileReader("output.txt");
            int character;
            while ((character = reader.read()) != -1) {
                System.out.print((char) character);
            }
            reader.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Standard I/O:
Java also provides access to standard input, output, and error streams using System.in, System.out, and System.err.

import java.util.Scanner;

public class StandardIOExample {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter your name: ");
        String name = scanner.nextLine();
        System.out.println("Hello, " + name + "!");
        scanner.close();
    }
}

The Java I/O system is powerful and versatile, allowing you to interact with various types of data sources and destinations. It’s important to handle exceptions properly when working with I/O operations and to close resources to prevent resource leaks.