java 通过 Spring Web-Socket 定期向客户端发送消息
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Sending message to client periodically via Spring Web-Socket
提问by ShakibaZar
I'm trying to make a connection between client and server via Spring webSocket and I'm doing this by the help of this link. I want Controller to send a "hello" to client every 5 seconds and client append it to the greeting box every time. This is the controller class:
我正在尝试通过 Spring webSocket 在客户端和服务器之间建立连接，并且我是在此链接的帮助下完成的。我希望控制器每 5 秒向客户端发送一个“你好”，客户端每次都将它附加到问候框中。这是控制器类：
@EnableScheduling
@Controller
public class GreetingController {
@Scheduled(fixedRate = 5000)
@MessageMapping("/hello")
@SendTo("/topic/greetings")
public Greeting greeting() throws Exception {
Thread.sleep(1000); // simulated delay
System.out.println("scheduled");
return new Greeting("Hello");
}
}
and This is Connect() function in app.jsp:
这是 app.jsp 中的 Connect() 函数：
function connect() {
var socket = new SockJS('/gs-guide-websocket');
stompClient = Stomp.over(socket);
stompClient.connect({}, function (frame) {
setConnected(true);
console.log('Connected: ' + frame);
stompClient.send("/app/hello", {}, JSON.stringify({'name': "connect"}));
stompClient.subscribe('/topic/greetings', function (message) {
console.log("message"+message);
console.log("message"+(JSON.parse(message.body)));
showGreeting(JSON.parse(message.body).content);
});
});
}
when the index.jsp loads and I press the connect button, only one time it appnds hello in greeting, how should I make client to show "hello" message every 5 seconds?
当 index.jsp 加载并且我按下连接按钮时，它只有一次在问候语中附加 hello，我应该如何让客户端每 5 秒显示一次“hello”消息？
回答by Andrei Balici
Please reffer to this portion of the documentation. The way you are trying to send a message is totally wrong. I would modify your above class as follows:
请参阅文档的这一部分。您尝试发送消息的方式是完全错误的。我会修改你上面的类如下：
@EnableScheduling
@Controller
public class GreetingController {
@Autowired
private SimpMessagingTemplate template;
@Scheduled(fixedRate = 5000)
public void greeting() {
Thread.sleep(1000); // simulated delay
System.out.println("scheduled");
this.template.convertAndSend("/topic/greetings", "Hello");
}
}
