Websocket实现方式二——注解方式

添加Websocket依赖

<dependency>
    <groupId>org.springframework.bootgroupId>
    <artifactId>spring-boot-starter-websocketartifactId>
dependency>

根据@ServerEndpoint注解注册Websocket

@Configuration
public class AgentWsConfig {

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

}

创建Websocket注解实现的类@ServerEndpoint注解标记类

@ServerEndpoint("/websocket/{sessionId}")
@Component
@Slf4j
public class AgentWsServerPoint {
    /**
     * websocket连接集合，根据Redis广播来的sessionId,来管理Session(取用和删除)
     */
    private static final Map<String, Session> SESSION_MAP = new ConcurrentHashMap<>();

    /**
     * 建立连接
     * @param sessionId
     * @param session
     */
    @OnOpen
    public void onOpen(@PathParam("sessionId") String sessionId, Session session) {
        SESSION_MAP.put(sessionId, session);
        log.info("WebSocket已打开，会话ID是：{}", sessionId);
        log.info(sessionId + "建立了连接");
    }

    /**
     * 接收消息并发送消息
     * @param sessionId
     * @param message
     * @param session
     * @return
     */
    @OnMessage
    public String onMessage(@PathParam(value = "sessionId") String sessionId,String message, Session session) throws Exception {
        log.info(sessionId + ":" + message);//客户端推送过来的消息
        
        Session session = SESSION_MAP.get(sessionId);
        try {
               session.getBasicRemote().sendText("Hello World!"); // 给特定用户发送消息
               log.info("消息发送成功");
            } catch (IOException e) {
                e.printStackTrace();
                log.error("消息发送失败");
                throw e;
            }
        return null;
    }

  
    /**
     * 关闭连接
     * @param sessionId
     * @param session
     */
    @OnClose
    public void onClose(@PathParam(value = "sessionId") String sessionId,Session session) throws IOException {
        if(SESSION_MAP.containsKey(sessionId)){
            Session session1 = SESSION_MAP.get(sessionId);
            session1.close();
            SESSION_MAP.remove(sessionId);
        }
        log.info("websocket is close ,session id is {}",sessionId);
    }
 }