如何使用Spring通过WebSocket向客户端发送消息 [英] How to send message to client through websocket using Spring

问题描述

我尝试将Spring与websocket一起使用.我从本教程开始调查.

I try to use Spring with websocket. I started my investigation with this tutorial.

在我的副客户端中，我有类似的东西来初始化与服务器的连接:

In my side client I have something like that to initialize the connection to the server :

function connect() {
    var socket = new SockJS('/myphotos/form');
    stompClient = Stomp.over(socket);
    stompClient.connect({}, function(frame) {
        setConnected(true);
        console.log('Connected: ' + frame);
        stompClient.subscribe('/topic/greetings', function(greeting){
            showGreeting(JSON.parse(greeting.body).content);
        });
    });
}

效果很好，在我的控制器中，我可以按照以下课程进行操作:

It works great, in my controller I’m able to do my process in the following class :

@Controller
@RequestMapping("/")
public class PhotoController {

    @MessageMapping("/form")
    @SendTo("/topic/greetings")
    public Greeting validate(AddPhotosForm addPhotosForm) {
        return new Greeting("Hello world !");
    }
}

现在我想要做的是有一个线程向侦听"/topic/greeting"的客户端发送消息.我这样写了Runnable类:

Now what I want to do it’s having a thread sending a message to the client listening on "/topic/greeting". I wrote my Runnable class like this :

public class FireGreeting implements Runnable {

    private PhotoController listener;

    public FireGreeting(PhotoController listener) {
        this.listener = listener;
    }

    @Override
    public void run() {
        while (true) {
            try {
                Thread.sleep( 2000 );
                listener.fireGreeting();
            } catch ( InterruptedException e ) {
                e.printStackTrace();
            }
        }   
    }
}

并像这样完成我的控制器:

And completed my controller like that :

@Controller
@RequestMapping("/")
public class PhotoController {

    @MessageMapping("/form")
    @SendTo("/topic/greetings")
    public Greeting validate(AddPhotosForm addPhotosForm) {

        // added this part
        FireGreeting r = new FireGreeting( this );
        new Thread(r).start();

        return new Greeting("Hello world !");
    }

    // added this method
    @SendTo("/topic/greetings")
    public Greeting fireGreeting() {
        System.out.println("Fire");
        return new Greeting("Fire");
    }
}

我需要调用PhotoController.fireGreeting方法，但是客户端没有任何反应. 有什么建议 ?谢谢.

The method PhotoController.fireGreeting is called as I want but nothing happened on the client side. Any suggestions ? Thank you.

推荐答案

感谢@Boris the Spider，我得以解决我的问题.正确的解决方案是执行以下操作:

I was able to solve my problem thanks to @Boris the Spider. The correct solution is to do something like that :

@Controller
@RequestMapping("/")
public class PhotoController {

    @Autowired
    private SimpMessagingTemplate template;

    @MessageMapping("/form")
    @SendTo("/topic/greetings")
    public Greeting validate(AddPhotosForm addPhotosForm) {

        FireGreeting r = new FireGreeting( this );
        new Thread(r).start();

        return new Greeting("Hello world !");
    }

    public void fireGreeting() {
        System.out.println("Fire");
        this.template.convertAndSend("/topic/greetings", new Greeting("Fire"));
    }
}

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