springboot+websocket 后台主动向前端推送消息

青旅半醒 2021-09-23 12:00 590阅读 0赞

最近做项目，用到后台需要实时向前台推送消息，看了很多例子，终于实现

idea工具，创建maven项目(这里就不多说了，可以直接用骨架搭建)

首先创建 WebSocketConfig 搭建websocket服务器

@Configuration
    @EnableWebSocketMessageBroker
    public class WebSocketConfig implements WebSocketMessageBrokerConfigurer {
        //消息主动推送
        @Override
        public void registerStompEndpoints(StompEndpointRegistry registry) {
            registry.addEndpoint("/socket").withSockJS();
        }
        //消息主动推送给指定用户
        @Override
        public void configureMessageBroker(MessageBrokerRegistry registry) {
            registry.enableSimpleBroker("/server","/user");
        }
    }

前端index.html页面，需要引入三个jar报，可以在[https://www.bootcdn.cn/][https_www.bootcdn.cn]下载

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Title</title>
        <script src="jquery.js"></script>
        <script src="sockjs.js"></script>
        <script src="stomp.js"></script>
    </head>
    <body>
    <div id="msg"></div>
    <script>
        var sockJS=new SockJS("http://localhost:8080/socket");
        var stompClient=Stomp.over(sockJS);
        stompClient.connect({},function(data){
            //订阅
            stompClient.subscribe("/server/sendMessageByServer",function (response) {
                $("#msg").append(response.body+"<br/>");
            })
        })
    </script>
    </body>
    </html>

推送指定user.html用户页面

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Title</title>
        <script src="jquery.js"></script>
        <script src="sockjs.js"></script>
        <script src="stomp.js"></script>
    </head>
    <body>
    ${id}
    <div id="msg"></div>
    <script>
        var id='${id}';
        var sockJS=new SockJS("http://localhost:8080/socket");
        var stompClient=Stomp.over(sockJS);
        stompClient.connect({},function(data){
            //订阅
            stompClient.subscribe("/user/"+id+"/server/sendMessageByServer",function (response) {
                $("#msg").append(response.body+"<br/>");
            })
        })
    </script>
    </body>
    </html>

controller实体类

@Controller
    @RequestMapping
    public class IndexController {
        @GetMapping("/")
        public String index(){
            return "index";
        }
        //发送指定用户
        @GetMapping("/user")
        public String user(Long id, ModelMap model){
            model.addAttribute("id",id);
            return "user";
        }
    }

MyJob类

@Configuration
    public class MyJob {
        @Autowired
        private SimpMessagingTemplate simpMessagingTemplate;
        @Scheduled(fixedRate = 1000)
        public void sendMessage(){
            System.out.println("来自服务端的消息");          
            simpMessagingTemplate.convertAndSend("/server/sendMessageByServer",System.currentTimeMillis());
        }
        @Scheduled(fixedRate = 10000)
        public void sendMessageToUser(){
            System.out.println("来自服务端的消息,推送给指定用户");
            simpMessagingTemplate.convertAndSendToUser("1","/server/sendMessageByServer",System.currentTimeMillis());
        }
    }

以上是全部代码：

运行springboot启动方法，启动成功后，浏览器访问

[http://localhost:8080/][http_localhost_8080]                              返回的是每隔1秒获取到的毫秒数

[http://localhost:8080/user?id=1][http_localhost_8080_user_id_1]              返回的是每隔10秒获取到的毫秒数

这里的id与MyJob类中

simpMessagingTemplate.convertAndSendToUser("1","/server/sendMessageByServer",System.currentTimeMillis());

的“1”对应，代表id为1的用户

大家可以灵活运用

simpMessagingTemplate.convertAndSend("/server/sendMessageByServer",System.currentTimeMillis());

或者

simpMessagingTemplate.convertAndSendToUser("1","/server/sendMessageByServer",System.currentTimeMillis());

可以放到大家需要推送的方法中

链接：https://pan.baidu.com/s/1p8Etfh3KH6jBrAmfhb-x9Q   
提取码：kz8a

[https_www.bootcdn.cn]: https://www.bootcdn.cn/
[http_localhost_8080]: http://localhost:8080/
[http_localhost_8080_user_id_1]: http://localhost:8080/user?id=1