WebSocket Spring Boot Example: A Complete Guide

WebSocket is a protocol that enables real-time communication between the client and server. Spring Boot is a popular framework for building web applications with Java. In this article, we will explore how to build a WebSocket application using Spring Boot.

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What is WebSocket?

WebSocket is a protocol that enables real-time communication between the client and server. Unlike traditional HTTP requests, WebSocket allows the server to send data to the client without the client requesting it. This enables real-time communication between the client and server, which is useful for applications that require real-time updates.

WebSocket is supported by most modern browsers and is widely used in web applications such as chat applications, real-time games, and financial applications.

What is Spring Boot?

Spring Boot is a popular framework for building web applications with Java. It provides a comprehensive set of tools for building web applications, including a web server, configuration management, and dependency injection.

Spring Boot makes it easy to build web applications with minimal configuration. It provides a set of starter projects that include all the necessary dependencies to get started with a particular technology stack. This makes it easy to get started with Spring Boot and reduces the amount of boilerplate code that needs to be written.

Getting Started with WebSocket and Spring Boot

In this section, we will explore how to build a WebSocket application using Spring Boot. We will start by creating a new Spring Boot project and adding the necessary dependencies.

Create a New Spring Boot Project

The first step is to create a new Spring Boot project. You can use any IDE of your choice to create a new Spring Boot project. In this example, we will use IntelliJ IDEA to create a new Spring Boot project.

Open IntelliJ IDEA and click on “New Project”.
Select “Spring Initializr” and click “Next”.
Enter a name for your project and select the appropriate settings for your project.
Select the necessary dependencies for your project. In this example, we will select “Spring Websocket” and “Thymeleaf”.
Click “Finish” to create the project.

Add the Necessary Dependencies

The next step is to add the necessary dependencies to your project. You can add the dependencies manually or use the IDE’s built-in dependency management tool.

In this example, we will use Maven to manage our project dependencies. To add the necessary dependencies, add the following code to your pom.xml file:

<dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-websocket</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-thymeleaf</artifactId></dependency></dependencies>

This will add the necessary dependencies for our WebSocket application.

Building a Simple WebSocket Application

In this section, we will explore how to build a simple WebSocket application using Spring Boot. We will create a simple chat application that allows users to send messages to each other in real-time.

Create a WebSocket Configuration Class

The first step is to create a WebSocket configuration class. This class will configure the WebSocket endpoint and message broker.

To create a WebSocket configuration class, add the following code to your project:

@Configuration@EnableWebSocketpublic class WebSocketConfig implements WebSocketConfigurer {@Overridepublic void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {registry.addHandler(new WebSocketHandler(), "/chat").setAllowedOrigins("*");}}

This code creates a WebSocket endpoint at “/chat” and allows all origins to access the endpoint.

Create a WebSocket Handler Class

The next step is to create a WebSocket handler class. This class will handle incoming WebSocket messages and send messages to other clients.

To create a WebSocket handler class, add the following code to your project:

public class WebSocketHandler extends TextWebSocketHandler {private static final List<WebSocketSession> sessions = new ArrayList<>();
@Overridepublic void afterConnectionEstablished(WebSocketSession session) throws Exception {sessions.add(session);}
@Overridepublic void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {for (WebSocketSession s : sessions) {s.sendMessage(message);}}}

This code creates a WebSocket handler that listens for incoming messages and sends them to all connected clients.

Create a Thymeleaf Template

The final step is to create a Thymeleaf template to display the chat application. To create a Thymeleaf template, add the following code to your project:

<!DOCTYPE html><html xmlns:th="http://www.thymeleaf.org"><head><title>WebSocket Chat</title></head><body><div><label>Username:</label><input type="text" id="username"/></div><div><label>Message:</label><input type="text" id="message"/><button onclick="send()">Send</button></div><div id="chat"></div><script>var socket = new WebSocket("ws://" + window.location.host + "/chat");socket.onmessage = function(event) {var message = JSON.parse(event.data);var chat = document.getElementById("chat");var p = document.createElement("p");var text = document.createTextNode(message.username + ": " + message.message);p.appendChild(text);chat.appendChild(p);};function send() {var username = document.getElementById("username").value;var message = document.getElementById("message").value;var data = {"username": username,"message": message};socket.send(JSON.stringify(data));}</script></body></html>

This code creates a simple chat application that allows users to send messages to each other in real-time.

Conclusion

WebSocket is a powerful protocol that enables real-time communication between the client and server. Spring Boot provides a comprehensive set of tools for building web applications with Java. By combining WebSocket and Spring Boot, we can build powerful real-time applications with minimal effort.

FAQ

What is WebSocket?

What is Spring Boot?

How do I create a WebSocket endpoint in Spring Boot?

To create a WebSocket endpoint in Spring Boot, create a WebSocket configuration class and add the necessary annotations to configure the WebSocket endpoint and message broker.

How do I handle incoming WebSocket messages in Spring Boot?

To handle incoming WebSocket messages in Spring Boot, create a WebSocket handler class and override the necessary methods to handle incoming messages.