Complete Guide to Java NIO

2 years ago
Olivia Parker
2 minutes

Java NIO, short for New I/O, is a new way of performing I/O operations in Java. Compared to traditional blocking I/O (BIO), it offers a more efficient way of handling I/O operations. Java NIO includes core components such as Channel, Buffer, and Selector, allowing users to directly manipulate Channel and Buffer for efficient non-blocking I/O operations.

The core concepts of Java NIO include the following parts:

  1. A Channel is an abstraction of a data source and data destination. It can be a file, network connection, pipe, and so on. Unlike traditional blocking I/O, Channels can perform reading and writing operations simultaneously without blocking.
  2. A buffer is a memory area used for temporarily storing data. It provides methods for reading and writing data, and can switch between reading and writing modes using the flip() method. There are various types of buffers, such as ByteBuffer, CharBuffer, and IntBuffer.
  3. The Selector is a multiplexor used to monitor the status of multiple Channels. With Selector, you can simultaneously listen for read and write events on multiple Channels and only handle them when events occur, avoiding the need for a thread to correspond to each connection in blocking I/O.

The main steps involved in using Java NIO typically include:

  1. Open Channel: Open an instance of Channel by calling the open() method of Channel.
  2. Bind Channel: Linking a Channel to a data source or destination, such as a file or network connection.
  3. Create a buffer: Instantiate a buffer based on the required data type.
  4. Read and write data: Perform read and write operations using the read() and write() methods of the Channel.
  5. Switching to Buffer mode: Switch between read and write modes using the flip() method of Buffer.
  6. Process data: Handle the data read as needed.
  7. Close Channel: Use the close() method of the Channel to close it.

Java NIO offers an efficient way to perform non-blocking I/O operations, allowing for handling numerous concurrent connections without the need for creating a large number of threads. However, compared to traditional blocking I/O, using Java NIO is more complex and requires more code to handle data. Therefore, when deciding whether to use Java NIO, it is important to carefully consider the specific circumstances.

bannerAds