Spring 中使用 WebSocket 笔记

编写 WebSocket 消息处理类，比较简单的方式就是直接继承AbstractWebSocketHandler，并覆写其中的处理方法，下面为一个简单的 demo

public class WebSocketHandler extends AbstractWebSocketHandler {
​
    @Override
    protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
        logger.info("Received message: " + message.getPayload());
        TimeUnit.SECONDS.sleep(2);
        session.sendMessage(new TextMessage("Polo!"));
    }
    
}

启用 WebSocket，并映射消息处理器

@Configuration
@EnableWebSocket
public class WebSocketConfig implements WebSocketConfigurer{
​
    // 要映射的 WebSocket 消息处理器(类)
    @Bean
    public WebSocketHandler webSocketHandler() {
        return new WebSocketHandler();
    }
    
    // 映射消息处理器到对应的路径
    @Override
    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
        registry.addHandler(webSocketHandler(), "/macro");
        
    }
​
}

之后即可在 javascript 端进行互相通信，demo 如下

var url = 'ws://' + window.location.host + '/demo/macro';
var sock = new WebSocket(url);
sock.onopen = function() {
    console.log("Opening");
    sayMarco();
}
        
sock.onmessage = function(e) {
    console.log("Received messaage: " + e.data);
    setTimeout(function(){sayMarco()}, 2000);
}
        
sock.onclose = function() {
    console.log("Closing");
}
        
function sayMarco() {
    console.log('Sending Marco!');
    sock.send('Marco!');
}