How do you configure a WebSocket endpoint in Spring Boot?

Table of Contents

• Introduction
• Steps to Configure a WebSocket Endpoint in Spring Boot
  • 1. Add Dependencies
    • Maven
    • Gradle
  • 2. Create a WebSocket Configuration Class
  • Explanation:
  • 3. Create a Custom WebSocket Handler
  • Explanation:
  • 4. Optional: Configure STOMP (for Messaging)
    • Create STOMP Configurator:
  • 5. Client-Side Implementation
    • Example with JavaScript and STOMP:
  • Explanation:
• Conclusion

Introduction

WebSockets provide a way to establish a persistent, two-way communication channel between the client and the server. Spring Boot makes it simple to configure WebSocket endpoints for real-time applications such as chat systems, live notifications, or real-time dashboards.

This guide will walk you through the process of setting up and configuring a WebSocket endpoint in Spring Boot.

Steps to Configure a WebSocket Endpoint in Spring Boot

1. Add Dependencies

To get started, include the necessary dependencies in your pom.xml for Maven or build.gradle for Gradle.

Maven

Gradle

This dependency will include everything needed to enable WebSocket support in your Spring Boot application.

2. Create a WebSocket Configuration Class

To enable WebSocket functionality in your application, you need to configure a WebSocketConfigurer class. This class will register the WebSocket endpoint and configure any other necessary settings.

Create a configuration class as follows:

Explanation:

• @Configuration: Marks the class as a Spring configuration class.
• @EnableWebSocket: Enables WebSocket support in your Spring application.
• registerWebSocketHandlers: Registers the WebSocket endpoint. In this case, it's /ws.
• myWebSocketHandler(): Returns the custom WebSocketHandler that will handle WebSocket connections.

3. Create a Custom WebSocket Handler

Now, you need to define a custom handler to handle WebSocket events like connection, messaging, and disconnection. This handler implements the WebSocketHandler interface.

Explanation:

• afterConnectionEstablished(): Called when a new WebSocket connection is established. Here you can add logic to initialize session data or other connection-related tasks.
• handleTextMessage(): Handles incoming text messages from the client. In this case, it sends a response back to the client with a simple message.
• afterConnectionClosed(): Called when the WebSocket connection is closed. You can add cleanup logic here.

4. Optional: Configure STOMP (for Messaging)

If you want to use STOMP (Simple Text Oriented Messaging Protocol) over WebSockets for message routing, you can configure it like this:

Create STOMP Configurator:

5. Client-Side Implementation

On the client side, you can use JavaScript to connect to your WebSocket endpoint.

Example with JavaScript and STOMP:

Explanation:

• SockJS: A JavaScript library that provides WebSocket-like functionality even in environments where WebSocket is not supported.
• STOMP Client: The STOMP protocol is used to communicate with the server over the WebSocket connection.

Conclusion

Configuring a WebSocket endpoint in Spring Boot involves adding the spring-boot-starter-websocket dependency, creating a WebSocketConfigurer class to register the endpoint, and implementing a custom WebSocket handler. Optionally, you can use STOMP for message routing over WebSocket connections, which is commonly used for real-time applications.

With this setup, you can easily implement real-time communication in your Spring Boot applications using WebSockets.