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websocket实现客户端跟服务端的双向传输,解决客户端向服务端轮训请求。应用到推送GPS位置信息,弹幕,聊天信息等场景。
一、Java服务端实现
maven依赖
org.springframework.boot spring-boot-starter-websocket
核心服务代码
@Configurationpublic class WebSocketConfig { @Bean public ServerEndpointExporter serverEndpointExporter() { return new ServerEndpointExporter(); }}
主要是OnOpen OnClose OnMessage OnError方法,里面再买上业务处理;
@Slf4j@ServerEndpoint(value = "/websocket/user/{accessToken}")@Component@EnableSchedulingpublic class WebSocketUserServer { //静态变量,用来记录当前在线连接数。应该把它设计成线程安全的。 private static AtomicInteger onlineCount = new AtomicInteger(0); //concurrent包的线程安全Set,用来存放每个客户端对应的MyWebSocket对象。 private static CopyOnWriteArrayListuserSockets = new CopyOnWriteArrayList<>(); //与某个客户端的连接会话,需要通过它来给客户端发送数据 private Session session; /* 连接打开时执行 */ @OnOpen public void onOpen(@PathParam("accessToken") String accessToken , Session session) { open:{ addOnlineCount(); //在线数加1 this.session = session; log.info("WebSocketUserServer 有新连接加入!当前在线人数为" + getOnlineCount()); if(accessToken ==null || "".equals(accessToken)){ log.info("WebSocketUserServer onOpen accessToken is null"); closeSession(session); break open; } //校验accessToken,获取user信息 //获取service方法 UcTokenFeign ucTokenFeign = SpringUtil.getBean(UcTokenFeign.class) ; ObjectRestResponse userResult = ucTokenFeign.getUserInfo(accessToken) ; if(userResult.getStatus() != CodeStatus.CODE_SUCCESS.getValue() ||userResult.getData() == null){ log.info("WebSocketUserServer onOpen token feign not success:"+userResult.getMsg()); closeSession(session); break open; } //添加到用户Session对应关系中 UserSocket userSocket = new UserSocket(); userSocket.setUserId(userResult.getData().getUserId()) userSocket.setWebSocketUserServer(this); userSockets.add(userSocket) ;// try {// sendMessage("server连接成功");// } catch (IOException e) {// log.error("websocket IO异常");// } log.info("WebSocketUserServer Connected ... " + session.getId()); } } /* 服务端不接收非合规的client,进行关闭操作 */ private void closeSession(Session session){ try { session.close(); } catch (IOException e) { log.error("WebSocketUserServer close error:"+e); e.printStackTrace(); } } /** * 连接关闭调用的方法 */ @OnClose public void onClose() { subOnlineCount(); //在线数减1 log.info("WebSocketUserServer 有一连接关闭!当前在线人数为" + getOnlineCount()); userSockets.stream() .forEach(u ->{ if(u.getWebSocketUserServer() == this){ userSockets.remove(u) ; log.info("WebSocketUserServer userSockets remove user socket,user:"+u.getUserId()); } } ); log.info("WebSocketUserServer 删除关闭连接的对应关系"); } /** * 收到客户端消息后调用的方法 * * @param message 客户端发送过来的消息*/ @OnMessage public void onMessage(String message, Session session) { log.info("WebSocketUserServer 来自客户端的消息:" + message);// //群发消息// for (WebSocketUserServer 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("WebSocketUserServer 发生错误:"+error); error.printStackTrace(); } /* 给客户端发送文本信息 */ public void sendMessage(String message) throws IOException { this.session.getBasicRemote().sendText(message); log.info("WebSocketUserServer sendMessage:"+message); } /* 发送用户状态信息 */ public void sendUserPushMsgInfo(String status) throws IOException{ this.session.getBasicRemote().sendText(status); log.info("WebSocketUserServer sendUserPushMsgInfo:"+status); } /* 根据userID给客户端推送用户状态 */ public static void PushMsgInfoToUser(String userId,String os ,String businessType,String status) throws IOException { if(status !=null && !"".equals(status)){ userSockets.stream() .forEach(u->{ if(u.getUserId().equals(userId)){ try { u.getWebSocketUserServer().sendUserPushMsgInfo(status); log.info("WebSocketUserServer PushMsgInfoToUser success,userId:"+userId); } catch (IOException e) { e.printStackTrace(); log.error("WebSocketUserServer PushMsgInfoToUser error,userId:"+userId); } } }); } } /* 定时检查存活的Session,如果未存活进行处理 */ @Scheduled(cron = "0 0/2 * * * ?") public static void checkAliveSession(){ log.info("WebSocketUserServer checkAliveSession start:"+new Date()); userSockets.stream() .forEach(u->{ if(!u.getWebSocketUserServer().session.isOpen()){ userSockets.remove(u) ; log.info("WebSocketUserServer checkAlive remove not open session,userId:"+u.getUserId()); } }); log.info("WebSocketUserServer checkAliveSession end:"+new Date()); } public static synchronized int getOnlineCount() { return onlineCount.get(); } public static synchronized void addOnlineCount() { WebSocketUserServer.onlineCount.getAndIncrement(); } public static synchronized void subOnlineCount() { WebSocketUserServer.onlineCount.getAndDecrement(); }}
二、websocket服务中引入service服务
采用辅助工具类SpringUtil获取Bean,
UcTokenFeign ucTokenFeign = SpringUtil.getBean(UcTokenFeign.class) ;
@Componentpublic class SpringUtil implements ApplicationContextAware { private static ApplicationContext applicationContext; @Override public void setApplicationContext(ApplicationContext applicationContext) throws BeansException { if(SpringUtil.applicationContext == null) { SpringUtil.applicationContext = applicationContext; } } //获取applicationContext public static ApplicationContext getApplicationContext() { return applicationContext; } //通过name获取 Bean. public static Object getBean(String name){ return getApplicationContext().getBean(name); } //通过class获取Bean. public staticT getBean(Class clazz){ return getApplicationContext().getBean(clazz); } //通过name,以及Clazz返回指定的Bean public static T getBean(String name,Class clazz){ return getApplicationContext().getBean(name, clazz); }}
三、websocket的分布式实现
1.session 放到redis中,实现数据共享,但是websocket session不支持序列号,存储不了
2.加入消息中间件,实现收到消息后的共享consumer有两种消费模式:集群消费和广播消费。集群消费:多个consumer平均消费该topic下所有mq的消息,即某个消息在某个message queue中被一个consumer消费后,其他消费者就不会消费到它;广播消费:所有consumer可以消费到发到这个topic下的所有消息。
因为Session不支持序列化,nginx分发不能保证一定指定到同一台服务器,特别移动互联网,移动设备下。
故采用消息订阅模式进行实现。每台服务器都订阅相同主题的消息,接收到消息后,关联到session则进行推送消息。
CopyOnWriteArrayListuserSockets = new CopyOnWriteArrayList<>() 这里便是维护关系点
四、客户端调用的html测试代码
WebSocket Chat
五、nginx配置
upstream websocket { server 1.203.115.27:8877; server 127.0.0.1:8877; } server { listen 8888; location / { proxy_pass http://websocket; proxy_http_version 1.1; proxy_set_header Upgrade $http_upgrade; proxy_set_header Connection "upgrade"; } }
六、zuul负载websocket
spring cloud zuul 1.x版本临时不直接支持spring websocket,到2.×版本会支持。
1.x版本也可以支持websocket,配置比较麻烦,需要结合sock.js stomp等。详细可以参考该网站:
七、断网、弱网、切换网等场景,实际使用的问题处理
待补充
八、websocket发送消息支持的长度大小
下面代码循环执行50000次,前端还可以接收到,不过已经需要好几秒的时间,这个时间延迟已经不低。
10W次也可以接收到,已经延迟到几分钟的程度。
循环次数 length
10000 33400 20000 66800 50000 16700011
100000 33400011
StringBuffer msg =new StringBuffer() ;// {"centerLat":"27.403234","centerLon":"117.504426","maxLat":"31.849878","maxLon":"121.434785","minLat":"22.956590","minLon":"113.574066","locations":[{"lon":"121.434785","lat":"31.849878","vehicleNo":"京AA8866","transportStatus":"0"},{"lon":"113.574066","lat":"22.956590","vehicleNo":"京ETYUUII","transportStatus":"0"}]} for(int i=0;i<100000;i++){ msg.append( " {\"centerLat\":\"27.403234\",\"centerLon\":\"117.504426\",\"maxLat\":\"31.849878\"" + ",\"maxLon\":\"121.434785\",\"minLat\":\"22.956590\",\"minLon\":\"113.574066\"" + ",\"locations\":[{\"lon\":\"121.434785\",\"lat\":\"31.849878\",\"vehicleNo\":\"京AA8866\",\"transportStatus\":\"0\"}" + ",{\"lon\":\"113.574066\",\"lat\":\"22.956590\",\"vehicleNo\":\"京ETYUUII\",\"transportStatus\":\"0\"}]}\n" ); } sendMessage("server连接成功;"+msg.toString());
九、支持SSL(https)
修改前端websocket连接代码,原本ws://需要改为wss://(购买或)生成密钥和证书,过程省略。需要注意的是:自己生成的证书在很多浏览器上会报警告,忽略后websocket仍然能用,如Chrom、Firefox,但有些浏览器不能用,如Safari。修改/etc/nginx/conf.d/mzsg.confupstream cat { server 172.168.0.2:8080 weight=5; server 172.168.0.2:7080 weight=5; }server { listen 443; server_name testsocket; access_log /data/logs/nginx/test.access.log; error_log /data/logs/nginx/test.error.log; ssl on; ssl_certificate cert/214745699540016.pem; ssl_certificate_key cert/214745699540016.key; ssl_session_timeout 5m; ssl_ciphers ECDHE-RSA-AES128-GCM-SHA256:ECDHE:ECDH:AES:HIGH:!NULL:!aNULL:!MD5:!ADH:!RC4; ssl_protocols TLSv1 TLSv1.1 TLSv1.2; ssl_prefer_server_ciphers on; location / { proxy_http_version 1.1; proxy_set_header Upgrade $http_upgrade; proxy_set_header Connection "upgrade"; proxy_set_header X-real-ip $remote_addr; proxy_set_header X-Forwarded-For $remote_addr; proxy_pass http://10.144.130.86:8877; }}
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