发送和接收 STOMP 消息
使用 STOMP 实现消息生产者和消费者,包括主题和面向特定用户的目标地址。
发送和接收 STOMP 消息 是 CoddyKit 上的免费 WebSockets & Real-Time Systems with Spring 课时。 这是第 3 节课,共 4 节。 你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。 这是 WebSockets & Real-Time Systems with Spring 学习路径的一部分,你的进度在网页和 CoddyKit 应用中同步。 WebSockets & Real-Time Systems with Spring 课程共包含 4 节课。
本课时的部分内容尚未翻译,以英文显示。
Intro to STOMP Messaging
In this lesson, we'll learn how to send messages from a client to our Spring server and how the server can then send messages back, either to a general topic or a specific user.
STOMP provides a clear, structured way to route these real-time messages, making our applications more predictable and easier to manage.
Producers and Consumers
Think of messaging in terms of producers and consumers:
- Producers send messages (e.g., a chat client sending a message).
- Consumers receive messages (e.g., another chat client displaying the message).
In a real-time app, clients often act as both!
Sending to Public Topics
A topic is a public destination. When a message is sent to a topic, all clients currently subscribed to that topic will receive the message.
It's like a broadcast channel or a public chat room where everyone hears what's said.
Common topic paths start with /topic/, e.g., /topic/public-chat or /topic/news-feed.
Server: Handling Topic Messages
On the Spring server, we use @MessageMapping to handle incoming messages from clients to a specific destination. We can then use SimpMessagingTemplate to send messages back out to a topic.
This snippet shows a server method receiving a message and then broadcasting it to a topic.
@Controller
public class ChatController {
@Autowired
private SimpMessagingTemplate messagingTemplate;
@MessageMapping("/chat.sendMessage")
public void sendMessage(@Payload String chatMessage) {
// Client sends to /app/chat.sendMessage
// Server broadcasts to /topic/public-chat
messagingTemplate.convertAndSend(
"/topic/public-chat", "New message: " + chatMessage);
}
}Client: Subscribing to Topics
On the client-side (e.g., JavaScript), you subscribe to a topic to receive messages. When the server sends a message to /topic/public-chat, all subscribed clients get it.
A client might subscribe like this:
stompClient.subscribe('/topic/public-chat', function(message) {
// Handle received message
});User-Specific Messaging
Sometimes you need to send a message directly to a single, specific user, not a public topic. This is called user-specific messaging.
It's perfect for:
- Private chat messages
- Personal notifications
- Direct alerts
STOMP and Spring handle the routing automatically for you.
Server: Sending to a User
Spring's SimpMessagingTemplate has a special method, convertAndSendToUser, to target messages to a specific user. You provide the username and the specific destination within that user's queue.
The framework translates /user/{username}/queue/messages into a unique queue for that user.
@Controller
public class UserController {
@Autowired
private SimpMessagingTemplate messagingTemplate;
@MessageMapping("/private.send")
public void sendPrivateMessage(
@Payload String privateMessage, Principal principal) {
// principal.getName() gets the current user's username
String recipient = "someOtherUser"; // This would come from payload
messagingTemplate.convertAndSendToUser(
recipient, "/queue/private-messages",
"From " + principal.getName() + ": " + privateMessage);
}
}Client: Subscribing to User Queue
A client subscribes to their own user-specific queue to receive private messages. The path usually looks like /user/queue/private-messages.
The key here is that the /user prefix is special. The STOMP broker automatically routes messages sent to a particular user to their unique session-specific queue.
Message Payloads
Messages sent over STOMP usually carry data in their payload (the message body). The most common format for this data is JSON.
Spring's STOMP support automatically converts Java objects to JSON (and vice-versa) when you use @Payload and convertAndSend methods, making it super easy to work with structured data.
Quick Check: STOMP Destinations
You want to send a personal notification to only one specific user. Which type of STOMP destination should you use?
Recap: Sending & Receiving
We've explored how to send and receive STOMP messages in Spring applications:
- Topics (e.g.,
/topic/public-chat) are for broadcasting messages to all subscribed clients. - User-specific destinations (e.g.,
/user/queue/private-messages) are for sending private messages to a single user. - Spring's
SimpMessagingTemplateand@MessageMappingannotations simplify both sending and receiving.
You can now build interactive features like chat rooms and private notifications!
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常见问题解答
「发送和接收 STOMP 消息」课时是免费的吗?
是的 — 「发送和接收 STOMP 消息」的完整文本可在网页上免费阅读。要进行交互式练习(内置代码编辑器和全天候 AI 导师)并解锁 WebSockets & Real-Time Systems with Spring 课程的其余内容,请升级到 CoddyKit PRO。 WebSockets & Real-Time Systems with Spring 课程共包含 4 节课。
「发送和接收 STOMP 消息」这节课中我会学到什么?
使用 STOMP 实现消息生产者和消费者,包括主题和面向特定用户的目标地址。 你通过在浏览器中直接运行的动手代码来练习 WebSockets & Real-Time Systems with Spring,全天候 AI 导师会在你学习这节课的过程中回答你的问题。
学习 WebSockets & Real-Time Systems with Spring 需要有经验吗?
无需任何先前经验。CoddyKit 上的 WebSockets & Real-Time Systems with Spring 课程适合初学者到高级学习者,你可以从这里开始或从头开始,按照自己的节奏学习。 这是第 3 节课,共 4 节。
「发送和接收 STOMP 消息」课时需要多长时间?
大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动,所以你能稳步进步,并在网页和应用中从离开的地方继续。
我能在这节 WebSockets & Real-Time Systems with Spring 课中编写并运行代码吗?
能。每节 WebSockets & Real-Time Systems with Spring 课都包含内置代码编辑器,你可以在浏览器中直接编写并运行真实代码,并获得即时 AI 反馈 — 无需本地设置。