Spring + StompWebsocket

Maven dependences

<dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-websocket</artifactId>
</dependency>
<dependency>
   <groupId>org.webjars</groupId>
   <artifactId>sockjs-client</artifactId>
   <version>1.1.2</version>
</dependency>
<dependency>
   <groupId>org.webjars</groupId>
   <artifactId>stomp-websocket</artifactId>
   <version>2.3.3-1</version>
</dependency>

HTML

<script src="/webjars/sockjs-client/1.1.2/sockjs.min.js"></script>
<script src="/webjars/stomp-websocket/2.3.3-1/stomp.min.js"></script>

Java config

@Configuration
@EnableWebSocketMessageBroker
public class WebSocketConfig implements WebSocketMessageBrokerConfigurer {
  
   @Override
   public void configureMessageBroker(MessageBrokerRegistry config) {
      config.enableSimpleBroker("/events”); // sending address to client
      config.setApplicationDestinationPrefixes("/ws-app”); //listen client message
   }
  
   @Override
   public void registerStompEndpoints(StompEndpointRegistry registry) {
      registry.addEndpoint("/websocket").withSockJS();
   }
  
}

JS

setConnected(connected) {
   this.connected = connected;
   console.log('connected: ', connected);
},
connect() {
   const socket = new SockJS('/websocket');
   this.stompClient = Stomp.over(socket);
   this.stompClient.connect({}, frame => {
      this.setConnected(true);
      this.stompClient.subscribe('/events/gate', res => {
         const data = JSON.parse(res.body);
         ...
      });
   });
},
disconnect() {
  
   if (this.stompClient !== null) {
      this.stompClient.disconnect();
   }
  
   this.setConnected(false);
}

Broadcast

@Autowired
private SimpMessageSendingOperations messagingTemplate;

public void broadcastEvent(String path, Object message) {
 messagingTemplate.convertAndSend("/events/" + path, message);
}