Websocket Session | Spring Session | Spring Framework Tutorial

Introduction to WebSocket Session

WebSocket is a communication protocol that provides full-duplex communication channels over a single TCP connection. It is especially useful for applications that require real-time data transfer, such as chat applications or live notifications. In the context of Spring Framework, WebSocket sessions can be managed to maintain user state across various connections.

Setting Up a Spring Boot Application

To start using WebSockets in a Spring application, we first need to set up a Spring Boot application. Here are the steps to create a simple Spring Boot application with WebSocket support.

Step 1: Create a Spring Boot Project

You can use Spring Initializr (https://start.spring.io/) to create a new Spring Boot project. Select the following dependencies:

Spring Web
Spring WebSocket
Spring Session

Configuring WebSocket

After setting up the project, we need to configure WebSocket. This can be done by creating a configuration class that extends AbstractWebSocketMessageBrokerConfigurer.

Configuration Example

import org.springframework.context.annotation.Configuration;
import org.springframework.messaging.simp.config.MessageBrokerRegistry;
import org.springframework.web.socket.config.annotation.EnableWebSocketMessageBroker;
import org.springframework.web.socket.config.annotation.StompEndpointRegistry;
import org.springframework.web.socket.config.annotation.WebSocketMessageBrokerConfigurer;

@Configuration
@EnableWebSocketMessageBroker
public class WebSocketConfig implements WebSocketMessageBrokerConfigurer {

    @Override
    public void configureMessageBroker(MessageBrokerRegistry config) {
        config.enableSimpleBroker("/topic");
        config.setApplicationDestinationPrefixes("/app");
    }

    @Override
    public void registerStompEndpoints(StompEndpointRegistry registry) {
        registry.addEndpoint("/ws").withSockJS();
    }
}

Creating WebSocket Controller

Next, we need to create a WebSocket controller to handle incoming messages and broadcast them to subscribers.

WebSocket Controller Example

import org.springframework.messaging.handler.annotation.MessageMapping;
import org.springframework.messaging.handler.annotation.SendTo;
import org.springframework.stereotype.Controller;

@Controller
public class ChatController {

    @MessageMapping("/chat")
    @SendTo("/topic/messages")
    public String sendMessage(String message) throws Exception {
        return message;
    }
}

Managing WebSocket Sessions

In Spring, you can manage sessions using Spring Session. This allows you to maintain user sessions across WebSocket connections.

Session Management Example

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.messaging.simp.SimpMessagingTemplate;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.HttpSession;

@RestController
public class SessionController {

    @Autowired
    private SimpMessagingTemplate messagingTemplate;

    @PostMapping("/send")
    public void sendMessage(HttpSession session, String message) {
        // Store session data
        session.setAttribute("lastMessage", message);
        // Send message to WebSocket
        messagingTemplate.convertAndSend("/topic/messages", message);
    }
}

Testing the WebSocket Application

You can test the WebSocket application using a simple HTML/JavaScript client. Below is an example of how to connect to the WebSocket server and send/receive messages.

HTML Client Example




    WebSocket Client

WebSocket Session Tutorial