Spring 上的客户端和服务器映射消息如何启动 websocket

Question

我在 github 上克隆了一个使用 spring 引导 websocket 的聊天应用程序项目。这是代码：

@MessageMapping("/chat.private.{username}")
public void filterPrivateMessage(@Payload ChatMessage message, @DestinationVariable("username") String username, Principal principal) {

    message.setUsername(principal.getName());
    simpMessagingTemplate.convertAndSend("/user/" + username + "/exchange/amq.direct/chat.message", message);
}

例如：用户名变量为：foo@gmail.com，表示客户端的link订阅应该是：/user/foo@gmail.com/exchange/amq.direct/chat.message

但是在客户端代码中：

chatSocket = Stomp.over(new SockJS(url)); //use sockjs and stompjs
chatSocket.subscribe("/user/exchange/amq.direct/chat.message"

我不明白当客户端收听不同的 url（没有 foo@gmail.com）时，应用程序如何发送给正确的客户端。有人可以给我解释一下吗？

谢谢。

Answer 1

关键是订阅url中的/user/前缀，会被Spring转化为特定用户投递消息。它在文档的 User Destinations 部分中进行了描述：

An application can send messages targeting a specific user, and Spring’s STOMP support recognizes destinations prefixed with /user/ for this purpose. For example, a client might subscribe to the destination /user/queue/position-updates. This destination will be handled by the UserDestinationMessageHandler and transformed into a destination unique to the user session, e.g. /queue/position-updates-user123. This provides the convenience of subscribing to a generically named destination while at the same time ensuring no collisions with other users subscribing to the same destination so that each user can receive unique stock position updates.

Spring 上的客户端和服务器映射消息如何启动 websocket

How client and server mapping message on Spring boot websocket

spring-boot

stomp

spring-websocket

sockjs