4.1.1.4.1. Using WebSocket to build an interactive web application

package com.example.messagingstompwebsocket;

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

@Controller
public class GreetingController {


    @MessageMapping("/hello")
    @SendTo("/topic/greetings")
    public Greeting greeting(HelloMessage message) throws Exception {
        Thread.sleep(1000); // simulated delay
        return new Greeting("Hello, " + HtmlUtils.htmlEscape(message.getName()) + "!");
    }

}

package com.example.messagingstompwebsocket;

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("/gs-guide-websocket").withSockJS();
    }

}

@EnableWebSocketMessageBroker: enables WebSocket message handling, backed by a message broker.

config.enableSimpleBroker(“/topic”): 订阅Broker名称，可以开启多个，例如：”/topic”,”queue”

setApplicationDestinationPrefixes：全局使用的消息前缀（客户端订阅路径上会体现出来）

function sendName() {
    stompClient.send("/app/hello", {}, JSON.stringify({'name': $("#name").val()}));
}

在客户端侧，使用stompClient发送消息时，需要指定一个前缀/app。