springboot websocket 消息推送

springboot websocket 实现消息推送

什么是WebSocket

WebSocket为浏览器和服务器之间提供了双工异步通信功能，也就是说我们可以利用浏览器给服务器发送消息，服务器也可以给浏览器发送消息，目前主流浏览器的主流版本对WebSocket的支持都算是比较好的，但是在实际开发中使用WebSocket工作量会略大，而且增加了浏览器的兼容问题，这种时候我们更多的是使用WebSocket的一个子协议stomp，利用它来快速实现我们的功能。

1.第一步

<dependency>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-starter-websocket</artifactId>
           <version>2.1.1.RELEASE</version>
       </dependency>

2.创建websocketConfig

@Configuration
@EnableWebSocketMessageBroker
@ComponentScan("com.sensetime.fis.senseguard")
public class WebSocketConfig implements WebSocketMessageBrokerConfigurer {

   @Autowired
   private PrincipalHandshakeHandler myDefaultHandshakeHandler;
   @Autowired
   private WebSocketInterceptor sessionAuthHandshakeInterceptor;

   /**
   * 配置消息代理类
   *
   * @param registry
   */
   @Override
   public void configureMessageBroker(MessageBrokerRegistry registry) {
       // 广播式应配置一个/topic消息代理
       // 推送消息前缀
       registry.enableSimpleBroker("/topic");
       // 应用请求前缀
       registry.setApplicationDestinationPrefixes("/app");
       // 推送用户前缀
       registry.setUserDestinationPrefix("/user");
   }

   @Override
   public void registerStompEndpoints(StompEndpointRegistry stompEndpointRegistry) {
       // 定义ws连接入口
       stompEndpointRegistry.addEndpoint("/websocket").setAllowedOrigins("*").addInterceptors(sessionAuthHandshakeInterceptor)
       .setHandshakeHandler(myDefaultHandshakeHandler).withSockJS()
               .setInterceptors(new WebSocketInterceptor());
   }

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

3.握手前配置 PrincipalHandshakeHandler

@Component
public class PrincipalHandshakeHandler extends DefaultHandshakeHandler {
   @Override
   protected Principal determineUser(ServerHttpRequest request, WebSocketHandler wsHandler,
           Map<String, Object> attributes) {
       HttpSession httpSession = getSession(request);
       String token = (String) httpSession.getAttribute("token");

       if (!StringUtils.isEmpty(token)) {
           return new ExportPrincipal(token);
       }
       return null;
   }

   private HttpSession getSession(ServerHttpRequest request) {
       ServletServerHttpRequest serverRequest = (ServletServerHttpRequest) request;
       return serverRequest.getServletRequest().getSession(true);
   }

4.拦截器配置 WebSocketInterceptor

/**
*
* @ClassName: MyWebSocketInterceptor
* @Description: 创建握手此类用来获取登录用户信息并交由websocket管理
* @author libo
* @date 2017年9月26日上午10:31:30
* HandshakeInterceptor WebSocket握手请求的拦截器. 检查握手请求和响应, 对WebSocketHandler传递属性
*/
@Component
public class WebSocketInterceptor extends TextWebSocketHandler implements HandshakeInterceptor {

   private Logger logger = LoggerFactory.getLogger(this.getClass());

   /**
   * 在握手之前执行该方法, 继续握手返回true, 中断握手返回false. 通过attributes参数设置WebSocketSession的属性
   */
   @Override
   public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler,
           Map<String, Object> attributes) throws Exception {
       HttpSession httpSession = getSession(request);
       String token = getToken(request.getURI().toString());
       httpSession.setAttribute("token", token);
       return true;
   }

   /**
   * 在握手之后执行该方法. 无论是否握手成功都指明了响应状态码和相应头.
   */
   @Override
   public void afterHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler,
           Exception exception) {
       String token = getToken(request.getURI().toString());
       logger.info("TOKEN为【{}】的用户建立消息连接已完成", token);
   }

   private String getToken(String uri) {
       int index = uri.indexOf("accessToken=");
       return uri.substring(index + 12, uri.length());
   }

   /**
   * 用户进入系统监听
   */
   @Override
   public void afterConnectionEstablished(WebSocketSession session) throws Exception {
       logger.info("xxx用户进入系统。。。");
       logger.info("用户信息:" + session.getAttributes());
       System.out.println(session.getAttributes());
       System.out.println("xxx用户进入系统。。。");

       Map<String, Object> map = session.getAttributes();
       for (String key : map.keySet()) {
           System.out.println("key:" + key + " and value:" + map.get(key));
       }
   }

   @SuppressWarnings("unused")
   private HttpSession getSession(ServerHttpRequest request) {
       ServletServerHttpRequest serverRequest = (ServletServerHttpRequest) request;
       return serverRequest.getServletRequest().getSession(true);
   }

5.推送

@Autowired
private SimpMessagingTemplate simpMessagingTemplate;

simpMessagingTemplate.convertAndSendToUser(task.getWebsocketId(), "/topic/records/subscribe", result);

后端整个流程就是这样了，前端简历连接订阅完成后，就可以接受后端给的推送消息。

springboot websocket 消息推送

springboot websocket 实现消息推送

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