Java NIO (New I/O) was introduced in Java 1.4 to provide a scalable and efficient I/O framework. Unlike the traditional I/O APIs in
java.io, NIO introduces the
java.nio package, offering features such as non-blocking I/O and memory-mapped files. In this tutorial, we’ll explore the fundamental concepts of Java NIO and walk through practical examples to illustrate its usage.
Before starting the examples, ensure you have:
- Java Development Kit (JDK) installed (version 8 or higher).
- An Integrated Development Environment (IDE) such as Eclipse or IntelliJ.
Example 1: Buffer Basics
Buffers are central to NIO and are used for reading and writing data. Let’s create a simple example that demonstrates the basic usage of buffers:
This example demonstrates the basic operations of creating a ByteBuffer, putting data into it, flipping it for reading, and then reading the data.
Example 2: Channels and File I/O
NIO introduces the concept of channels for performing I/O operations. Let’s create an example to copy data from one file to another using channels:
In this example, we use the
FileChannel class to copy data from one file to another. The
transferTo method efficiently transfers data between channels.
Example 3: Asynchronous I/O
Java NIO supports asynchronous I/O operations through the
AsynchronousFileChannel classes. Let’s create an example to read a file asynchronously:
This example demonstrates asynchronous file reading using
read method returns a
Future that can be used to check if the operation is complete.
Java NIO provides a powerful and scalable I/O framework, offering features such as buffers, channels, and asynchronous I/O. This tutorial covered basic buffer operations, file I/O using channels, and asynchronous file reading. As you explore further, you’ll discover additional capabilities of Java NIO, making it a valuable tool for efficient and responsive I/O operations in your Java applications.