Does Netty use Servlet?

Does Netty use Servlet?

Netty is a highly performant, non-blocking I/O framework for building network applications. Unlike Jetty, it does not follow the Java Servlet model but instead operates on event loops.

 

• Netty :
  • 비동기 이벤트 기반의 네트워크 애플리케이션을 개발하기 위한 프레임워크 비동기? - 처리될 때까지 기다리는 것이 아니라 요청은 요청대로, 응답은 응답대로 따로 하는 것 → 독립적으로 돌아가는 행위
    • ex) Ajax
  • 주로 고성능, 확장 가능한 네트워크 서버를 개발하는데 사용 → 처리를 기다리지 않고 바로 다른 작업을 진행할 수 있으니까
  • 보통 웹, 게임, 채팅, 프록시 서버 등과 같은 네트워크 기반의 어플리케이션을 개발하는데 활용 → 언제 요청이 들어올지 모르는데, 요청이 들어오면 즉각처리해줘야하는 것들 중 성능이 요구되는 서비스에 사용된다.
• Tomcat :
  • 서블릿(Servlet) 컨테이너로서, JSP와 Servlet 기술을 사용하여 Java 웹 애플리케이션을 실행하는데 사용
  • 동시성 처리보다는 싱글 스레드 형식( 단일 요청→단일 응답 처리 )에 적합

---

What is event loop in Netty?

The event loop in Netty is a crucial component of its asynchronous, event-driven architecture. It's essentially a single-threaded loop that handles I/O operations for one or more channels. Here's a breakdown: 

 

Core Functionality

 

• Single-Threaded:

  Each EventLoop runs on its own thread, ensuring that events for a specific channel are processed sequentially, eliminating the need for complex synchronization mechanisms.

   
• Event Processing:

  The EventLoop continuously monitors for I/O events such as accepting new connections, reading data from sockets, and writing data to sockets.

   
• Task Queue:

  It manages a queue of tasks, executing them one by one in the order they were submitted. This includes user-defined tasks and callbacks. 

   
• Channel Lifecycle:

  The EventLoop is responsible for the lifecycle of channels, including registration, deregistration, and closing.

   

How it Works

 

• Event Detection:

  The EventLoop waits for I/O events to occur on the channels it manages.
• Event Dispatch:

  When an event occurs, the EventLoop dispatches it to the appropriate handler.
• Task Execution:

  The handler processes the event and may submit additional tasks to the EventLoop's queue.
• Looping:

  The EventLoop continues to process events and execute tasks in a loop, ensuring that all operations are handled efficiently and asynchronously.

Key Benefits

 

• Non-Blocking I/O:

  The EventLoop enables non-blocking I/O operations, allowing Netty to handle a large number of concurrent connections with a minimal number of threads.
• Performance:

  By avoiding thread context switching, the EventLoop improves performance and reduces overhead.
• Simplicity:

  It simplifies the management of concurrent operations, making it easier to build highly scalable and responsive applications.

In summary, the EventLoop is the heart of Netty's asynchronous processing model, providing a single-threaded, event-driven approach to handling I/O operations and tasks.