Spring Stomp WebSocket: The Ultimate Guide

WebSockets have been around for a while, but with the introduction of Spring Stomp, the game has completely changed. In this article, we will explore everything you need to know about Spring Stomp WebSocket and how it can revolutionize the way you develop real-time applications. So, let’s dive in!

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What is Spring Stomp?

Spring Stomp is a subproject of the Spring Framework that provides WebSocket and STOMP (Streaming Text Oriented Messaging Protocol) support for building real-time applications. With Spring Stomp, developers can easily create scalable and efficient WebSocket applications that can handle a large number of concurrent connections.

What are WebSockets?

WebSockets are a protocol that enables bidirectional communication between a client and a server over a single TCP connection. Unlike traditional HTTP requests, WebSockets keep the connection open, allowing for real-time communication between the client and the server. This makes WebSockets an ideal choice for building real-time applications such as chat applications, multiplayer games, and stock market applications.

What is STOMP?

STOMP is a messaging protocol that provides an interoperable way for clients to communicate with message brokers such as ActiveMQ, RabbitMQ, and Apache Kafka. STOMP is a simple protocol that uses a text-based format, making it easy to implement in different programming languages.

Getting Started with Spring Stomp WebSocket

Prerequisites

Before we dive into building a Spring Stomp WebSocket application, let’s make sure we have the following prerequisites:

Java 8 or later
Maven or Gradle
An IDE such as IntelliJ IDEA or Eclipse

Creating a Spring Boot Application

The easiest way to get started with Spring Stomp WebSocket is to create a new Spring Boot application. Spring Boot provides a convenient way to set up a new project with all the necessary dependencies.

To create a new Spring Boot application, follow these steps:

Open your IDE and create a new Maven or Gradle project.
Add the following dependencies to your project:

Maven

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

Gradle

implementation 'org.springframework.boot:spring-boot-starter-websocket'

Create a new class called WebSocketConfig and add the following code:

@Configuration@EnableWebSocketMessageBrokerpublic class WebSocketConfig implements WebSocketMessageBrokerConfigurer {@Overridepublic void configureMessageBroker(MessageBrokerRegistry config) {config.enableSimpleBroker("/topic");config.setApplicationDestinationPrefixes("/app");}
@Overridepublic void registerStompEndpoints(StompEndpointRegistry registry) {registry.addEndpoint("/websocket").withSockJS();}}

This code configures the WebSocket message broker and sets up the endpoint for the WebSocket connection.

Creating a WebSocket Controller

Now that we have set up our Spring Boot application and WebSocket configuration, let’s create a WebSocket controller that will handle incoming WebSocket messages.

To create a WebSocket controller, follow these steps:

Create a new class called WebSocketController and add the following code:

@Controllerpublic class WebSocketController {@MessageMapping("/hello")@SendTo("/topic/greetings")public Greeting greeting(HelloMessage message) throws Exception {Thread.sleep(1000); // simulated delayreturn new Greeting("Hello, " + message.getName() + "!");}
public static class HelloMessage {
private String name;
public String getName() {return name;}
public void setName(String name) {this.name = name;}}
public static class Greeting {
private String content;
public Greeting(String content) {this.content = content;}
public String getContent() {return content;}}}

This code creates a WebSocket controller that listens for incoming messages on the /hello endpoint and sends a response to the /topic/greetings endpoint.

Testing the WebSocket Connection

Now that we have set up our Spring Stomp WebSocket application, let’s test the connection using a WebSocket client. We will be using the StompJS library to connect to our WebSocket server.

To test the WebSocket connection, follow these steps:

Create a new HTML file called index.html and add the following code:

<!DOCTYPE html><html><head><title>Spring Stomp WebSocket</title><script src="https://code.jquery.com/jquery-3.5.1.min.js"></script><script src="https://cdnjs.cloudflare.com/ajax/libs/stomp.js/2.3.3/stomp.min.js"></script></head><body><div id="greetings"></div><form id="message-form"><input type="text" id="name" placeholder="Enter your name"><button type="submit">Send</button></form><script>var stompClient = null;function connect() {var socket = new SockJS('/websocket');stompClient = Stomp.over(socket);stompClient.connect({}, function (frame) {console.log('Connected: ' + frame);stompClient.subscribe('/topic/greetings', function (greeting) {showGreeting(JSON.parse(greeting.body).content);});});}
function disconnect() {if (stompClient !== null) {stompClient.disconnect();}console.log("Disconnected");}
function sendName() {var name = $('#name').val();stompClient.send("/app/hello", {}, JSON.stringify({ 'name': name }));}
function showGreeting(message) {$('#greetings').append('<div>' + message + '</div>');}
$(function () {$('form').on('submit', function (e) {e.preventDefault();});connect();$('#send').click(function() { sendName(); });$(window).on('beforeunload', function(){disconnect();});});</script></body></html>

This code sets up a WebSocket client that connects to the /websocket endpoint and sends messages to the /app/hello endpoint.

Start your Spring Boot application and open the index.html file in your web browser.
Enter your name in the input field and click the Send button.

You should see a greeting message appear on the page. Congratulations, you have successfully created a Spring Stomp WebSocket application!

Conclusion

Spring Stomp WebSocket provides a powerful and efficient way to build real-time applications. With Spring Stomp, developers can easily create scalable and efficient WebSocket applications that can handle a large number of concurrent connections. In this article, we have explored the basics of Spring Stomp WebSocket and how to create a simple WebSocket application. We hope this article has been helpful in getting you started with Spring Stomp WebSocket.

FAQ

What is the difference between WebSockets and HTTP?

HTTP is a request-response protocol that is used to retrieve resources from a server. WebSockets, on the other hand, provide bidirectional communication between a client and a server over a single TCP connection.

What is the difference between STOMP and MQTT?

STOMP and MQTT are both messaging protocols that provide an interoperable way for clients to communicate with message brokers. The main difference between the two protocols is that STOMP is a text-based protocol, while MQTT is a binary protocol. Additionally, STOMP provides more advanced features such as message headers and transactions.