Websocket

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-websocket</artifactId>
</dependency>

import org.springframework.context.annotation.Bean;
import org.springframework.stereotype.Component;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;

@Component
public class WebSocketCfg {

    @Bean
    public ServerEndpointExporter serverEndpointExporter(){
        return new ServerEndpointExporter();
    }
}

import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;

import javax.websocket.OnClose;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.ServerEndpoint;
import java.util.concurrent.CopyOnWriteArraySet;

/**
 * @ServerEndpoint 注解是一个类层次的注解，它的功能主要是将目前的类定义成一个websocket服务器端,
 * 注解的值将被用于监听用户连接的终端访问URL地址,客户端可以通过这个URL来连接到TLWebSocket服务器端
 */
@Component
@ServerEndpoint("/websocket")
@Slf4j
public class TLWebSocket {

    private Session session;

    private static CopyOnWriteArraySet<TLWebSocket> webSocketSet=new CopyOnWriteArraySet<>();

    @OnOpen
    public void onOpen(Session session){
        this.session=session;
        webSocketSet.add(this);
        log.info("【websocket消息】 有新的连接，总数：{}",webSocketSet.size());
    }

    @OnClose
    public void onClose(){
        webSocketSet.remove(this);
        log.info("【websocket消息】 连接断开，总数：{}",webSocketSet.size());
    }

    @OnMessage
    public void onMessage(String message){
        log.info("【websocket消息】 收到客户端发来的消息：{}",message);
    }

    public void sendMessage(String message){
        for(TLWebSocket webSocket:webSocketSet){
            log.info("【websocket消息】 广播消息，message={}",message);
            try {
                webSocket.session.getBasicRemote().sendText(message);
            }catch (Exception e){
                e.printStackTrace();
            }
        }
    }
}

@Autowired
 private TLWebSocket webSocket;

 @RequestMapping(value ="/myWebSkt/startup",method = RequestMethod.POST)
    public void startup() {
        try {
            webSocket.sendMessage("server call client");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

let websocket = null;
  if ('WebSocket' in window) {
    websocket = new WebSocket("ws://localhost:8000/web/websocket");
    //连接发生错误的回调方法
    websocket.onerror = function () {
      setMessageInnerHTML("WebSocket连接发生错误");
      closeWebSocket()
    };

//连接成功建立的回调方法
    websocket.onopen = function () {
      setMessageInnerHTML("WebSocket连接成功");
    }

//接收到消息的回调方法
    websocket.onmessage = function (event) {
      setMessageInnerHTML("server => "+ event.data);
    }

//连接关闭的回调方法
    websocket.onclose = function () {
      setMessageInnerHTML("WebSocket连接关闭");
    }
  }
  else {
    alert('当前浏览器 Not support websocket')
  }

//监听窗口关闭事件，当窗口关闭时，主动去关闭websocket连接，防止连接还没断开就关闭窗口，server端会抛异常。
window.onbeforeunload = function () {
  closeWebSocket();
}
//将消息显示在网页上
  function setMessageInnerHTML(innerHTML) {
  console.log(innerHTML)
  // document.getElementById('message').innerHTML += innerHTML + '<br/>';
}

//关闭WebSocket连接
  function closeWebSocket() {
    websocket.close();
}

//发送消息
  function sendMsg (msg){
  setMessageInnerHTML("client => "+ msg);
  websocket.send(msg);
}

export {
  websocket,setMessageInnerHTML,closeWebSocket,sendMsg
}

this.$htp.post_("/myWebSkt/startup")    //后台调用发送webSocket消息到前端
  .then(res => {
    console.log(res)
  })