Shulou(Shulou.com)06/02 Report--

In this issue, Xiaobian will bring you about how to use Websocket in spring boot. The article is rich in content and analyzed and described from a professional perspective. After reading this article, I hope you can gain something.

There are two ways to use websocket: 1) using sockjs, and 2) using h6 standards. Html5 standard is naturally more convenient and simple to use, so the record is to cooperate with the use of h6.

1、pom

The core is the @ServerEndpoint annotation. This annotation is a Javaee standard annotation, tomcat7 above has been implemented, if you are using the traditional method of publishing tomcat projects, as long as the introduction of javaee standards in the pom file can be used.

javax javaee-api 7.0 provided

But when using springboot's built-in tomcat, there is no need to introduce javaee-api, spring-boot is already included. The websocket functionality using springboot is first introduced into the springboot component.

org.springframework.boot spring-boot-starter-websocket 1.3.5.RELEASE

By the way, the advanced components of springboot automatically reference the base components, such as spring-boot-starter-websocket, which introduces spring-boot-starter-web and spring-boot-starter, so don't repeat them.

Create a websocket endpoint using @ServerEndpoint

First inject ServerEndpointExporter, which automatically registers Websocket endpoints declared with the @ServerEndpoint annotation. Note that if you use a standalone servlet container instead of using springboot's built-in container directly, don't inject ServerEndpointExporter, as it will be provided and managed by the container itself.

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

@ServerEndpoint(value = "/websocket")@Componentpublic class MyWebSocket { //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 int onlineCount = 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 CopyOnWriteArraySet webSocketSet = new CopyOnWriteArraySet(); //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; /** * 连接建立成功调用的方法*/ @OnOpen public void onOpen(Session session) { this.session = session; webSocketSet.add(this); //加入set中 addOnlineCount(); //在线数加1 System.out.println("有新连接加入!当前在线人数为" + getOnlineCount()); try { sendMessage(CommonConstant.CURRENT_WANGING_NUMBER.toString()); } catch (IOException e) { System.out.println("IO异常"); } } /** * 连接关闭调用的方法 */ @OnClose public void onClose() { webSocketSet.remove(this); //从set中删除 subOnlineCount(); //在线数减1 System.out.println("有一连接关闭!当前在线人数为" + getOnlineCount()); } /** * 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) { System.out.println("来自客户端的消息:" + message); //群发消息 for (MyWebSocket item : webSocketSet) { try { item.sendMessage(message); } catch (IOException e) { e.printStackTrace(); } } } /** * 发生错误时调用 @OnError public void onError(Session session, Throwable error) { System.out.println("发生错误"); error.printStackTrace(); } public void sendMessage(String message) throws IOException { this.session.getBasicRemote().sendText(message); //this.session.getAsyncRemote().sendText(message); } /** * 群发自定义消息 * */ public static void sendInfo(String message) throws IOException { for (MyWebSocket item : webSocketSet) { try { item.sendMessage(message); } catch (IOException e) { continue; } } } public static synchronized int getOnlineCount() { return onlineCount; } public static synchronized void addOnlineCount() { MyWebSocket.onlineCount++; } public static synchronized void subOnlineCount() { MyWebSocket.onlineCount--; }}

使用springboot的唯一区别是要@Component声明下，而使用独立容器是由容器自己管理websocket的，但在springboot中连容器都是spring管理的。

虽然@Component默认是单例模式的，但springboot还是会为每个websocket连接初始化一个bean，所以可以用一个静态set保存起来。

3、前端代码

My WebSocketWelcome 4、总结 springboot已经做了深度的集成和优化，要注意是否添加了不需要的依赖、配置或声明。由于很多讲解组件使用的文章是和spring集成的，会有一些配置，在使用springboot时，由于springboot已经有了自己的配置，再这些配置有可能导致各种各样的异常。上述就是小编为大家分享的spring boot 中如何使用Websocket了，如果刚好有类似的疑惑，不妨参照上述分析进行理解。如果想知道更多相关知识，欢迎关注行业资讯频道。

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