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

@Configuration
public class WebSocketConfig {
    @Bean
    public ServerEndpointExporter serverEndpointExporter(){
        return new ServerEndpointExporter();
    }
}
3.3、創(chuàng)建WebSokcet工具類
 
@ServerEndpoint(value = "/websocket")
@Component
public class WebSocketServer {
    private final static Logger log = LoggerFactory.getLogger(WebSocketServer.class);
 
    //靜態(tài)變量，用來記錄當(dāng)前在線連接數(shù)。應(yīng)該把它設(shè)計(jì)成線程安全的。
    private static int onlineCount = 0;
    //concurrent包的線程安全Set，用來存放每個客戶端對應(yīng)的MyWebSocket對象。
    private static CopyOnWriteArraySet<WebSocketServer> webSocketSet = new CopyOnWriteArraySet<WebSocketServer>();
 
    //與某個客戶端的連接會話，需要通過它來給客戶端發(fā)送數(shù)據(jù)
    private Session session;
 
    /**
     * 連接建立成功調(diào)用的方法
     */
    @OnOpen
    public void onOpen(Session session) {
        this.session = session;
        //加入set中
        webSocketSet.add(this);
        //在線數(shù)加1
        addOnlineCount();
        log.info("有新連接加入！當(dāng)前在線人數(shù)為" + getOnlineCount());
        try {
            MsgResponseVo userMsgResponseVo = new MsgResponseVo();
            userMsgResponseVo.setMsg("SUCCESS");
            WebSocketServer.sendInfo(JSON.toJSONString(userMsgResponseVo));
        } catch (IOException e) {
            log.error("websocket IO異常");
        }
    }
 
    /**
     * 連接關(guān)閉調(diào)用的方法
     */
    @OnClose
    public void onClose() {
        //從set中刪除
        webSocketSet.remove(this);
        //在線數(shù)減1
        subOnlineCount();
        log.info("有一連接關(guān)閉！當(dāng)前在線人數(shù)為" + getOnlineCount());
    }
 
    /**
     * 收到客戶端消息后調(diào)用的方法
     *
     * @param message 客戶端發(fā)送過來的消息
     */
    @OnMessage
    public void onMessage(String message, Session session) {
        log.info("來自客戶端的消息:" + message);
 
        //群發(fā)消息
        for (WebSocketServer item : webSocketSet) {
            try {
                item.sendMessage(message);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
 
    /**
     * @param session
     * @param error
     */
    @OnError
    public void onError(Session session, Throwable error) {
        log.error("發(fā)生錯誤");
        error.printStackTrace();
    }
 
    public void sendMessage(String message) throws IOException {
        this.session.getBasicRemote().sendText(message);
    }
 
    /**
     * 群發(fā)自定義消息
     */
    public static void sendInfo(String message) throws IOException {
        log.info(message);
        for (WebSocketServer item : webSocketSet) {
            try {
                item.sendMessage(message);
            } catch (IOException e) {
                continue;
            }
        }
    }
 
    public static synchronized int getOnlineCount() {
        return onlineCount;
    }
 
    public static synchronized void addOnlineCount() {
        WebSocketServer.onlineCount++;
    }
 
    public static synchronized void subOnlineCount() {
        WebSocketServer.onlineCount--;
    }
}

 @GetMapping("/testWebSocket")
    public ApiRestResponse testWebSocket() throws IOException {
        //消息體
        MsgResponseVo technicianMsgResponseVo = new MsgResponseVo();
        technicianMsgResponseVo.setRole("Technician");
        technicianMsgResponseVo.setRoleId(1);
        technicianMsgResponseVo.setMsg("您的訂單已取消");
        technicianMsgResponseVo.setMsgStatus("CANCEL_ORDER");
        technicianMsgResponseVo.setOrderNo("test");
        //發(fā)送消息
        WebSocketServer.sendInfo(JSON.toJSONString(technicianMsgResponseVo));
        return ApiRestResponse.success();
    }
}