Spring+Websocket实现消息的推送

Websocet服务端实现

WebSocketConfig.java

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@Configuration @EnableWebMvc @EnableWebSocket public class WebSocketConfig extends WebMvcConfigurerAdapter implements WebSocketConfigurer {      @Override      public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {          registry.addHandler(systemWebSocketHandler(), "/webSocketServer" ).addInterceptors( new WebSocketHandshakeInterceptor());            registry.addHandler(systemWebSocketHandler(), "/sockjs/webSocketServer" ).addInterceptors( new WebSocketHandshakeInterceptor())                  .withSockJS();      }        @Bean      public WebSocketHandler systemWebSocketHandler(){          return new SystemWebSocketHandler();      }   }

不要忘记在springmvc的配置文件中配置对此类的自动扫描

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1	< context:component-scan base-package = "com.ldl.origami.websocket" />

@Configuration

@EnableWebMvc
@EnableWebSocket
这三个大致意思是使这个类支持以@Bean的方式加载bean，并且支持springmvc和websocket，不是很准确大致这样，试了一下@EnableWebMvc不加也没什么影响，@Configuration本来就支持springmvc的自动扫描

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1	registry.addHandler(systemWebSocketHandler(), "/webSocketServer" ).addInterceptors( new WebSocketHandshakeInterceptor())

用来注册websocket server实现类，第二个参数是访问websocket的地址

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registry.addHandler(systemWebSocketHandler(), "/sockjs/webSocketServer" ).addInterceptors( new WebSocketHandshakeInterceptor())                  .withSockJS();      }

这个是使用Sockjs的注册方法

首先SystemWebSocketHandler.java

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public class SystemWebSocketHandler implements WebSocketHandler {        private static final Logger logger;        private static final ArrayList<WebSocketSession> users;        static {          users = new ArrayList<>();          logger = LoggerFactory.getLogger(SystemWebSocketHandler. class );      }        @Autowired      private WebSocketService webSocketService;        @Override      public void afterConnectionEstablished(WebSocketSession session) throws Exception {          logger.debug( "connect to the websocket success......" );          users.add(session);          String userName = (String) session.getAttributes().get(Constants.WEBSOCKET_USERNAME);          if (userName!= null ){              //查询未读消息              int count = webSocketService.getUnReadNews((String) session.getAttributes().get(Constants.WEBSOCKET_USERNAME));                session.sendMessage( new TextMessage(count + "" ));          }      }        @Override      public void handleMessage(WebSocketSession session, WebSocketMessage<?> message) throws Exception {            //sendMessageToUsers();      }        @Override      public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {          if (session.isOpen()){              session.close();          }          logger.debug( "websocket connection closed......" );          users.remove(session);      }        @Override      public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception {          logger.debug( "websocket connection closed......" );          users.remove(session);      }        @Override      public boolean supportsPartialMessages() {          return false ;      }        /**       * 给所有在线用户发送消息       *       * @param message       */      public void sendMessageToUsers(TextMessage message) {          for (WebSocketSession user : users) {              try {                  if (user.isOpen()) {                      user.sendMessage(message);                  }              } catch (IOException e) {                  e.printStackTrace();              }          }      }        /**       * 给某个用户发送消息       *       * @param userName       * @param message       */      public void sendMessageToUser(String userName, TextMessage message) {          for (WebSocketSession user : users) {              if (user.getAttributes().get(Constants.WEBSOCKET_USERNAME).equals(userName)) {                  try {                      if (user.isOpen()) {                          user.sendMessage(message);                      }                  } catch (IOException e) {                      e.printStackTrace();                  }                  break ;              }          }      } }

相关内容大家一看就能明白，就不多解释了

然后WebSocketHandshakeInterceptor.java

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public class WebSocketHandshakeInterceptor implements HandshakeInterceptor {        private static Logger logger = LoggerFactory.getLogger(HandshakeInterceptor. class );      @Override      public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Map<String, Object                  > attributes) throws Exception {          if (request instanceof ServletServerHttpRequest) {              ServletServerHttpRequest servletRequest = (ServletServerHttpRequest) request;              HttpSession session = servletRequest.getServletRequest().getSession( false );              if (session != null ) {                  //使用userName区分WebSocketHandler，以便定向发送消息                  String userName = (String) session.getAttribute(Constants.SESSION_USERNAME);                  attributes.put(Constants.WEBSOCKET_USERNAME,userName);              }          }          return true ;      }        @Override      public void afterHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Exception exception) {        } }

这个的主要作用是取得当前请求中的用户名，并且保存到当前的WebSocketHandler中，以便确定WebSocketHandler所对应的用户，具体可参考HttpSessionHandshakeInterceptor

用户登录建立websocket连接

index.jsp

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<script type= "text/javascript" src= "http://localhost:8080/Origami/websocket/sockjs-0.3.min.js" ></script>          <script>              var websocket;              if ( 'WebSocket' in window) {                  websocket = new WebSocket( "ws://localhost:8080/Origami/webSocketServer" );              } else if ( 'MozWebSocket' in window) {                  websocket = new MozWebSocket( "ws://localhost:8080/Origami/webSocketServer" );              } else {                  websocket = new SockJS( "http://localhost:8080/Origami/sockjs/webSocketServer" );              }              websocket.onopen = function (evnt) {              };              websocket.onmessage = function (evnt) {                  $( "#msgcount" ).html( "(<font color='red'>" +evnt.data+ "</font>)" )              };              websocket.onerror = function (evnt) {              };              websocket.onclose = function (evnt) {              }            </script>

使用sockjs时要注意

1、这两个的写法

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1	<script type= "text/javascript" src= "http://localhost:8080/Origami/websocket/sockjs-0.3.min.js" ></script>

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1	websocket = new SockJS( "http://localhost:8080/Origami/sockjs/webSocketServer" );

2、web.xml中

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< web-app version = "3.0" xmlns = "http://java.sun.com/xml/ns/javaee"      xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance"      xsi:schemaLocation = "http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_1.xsd" >

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version

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1	web-app_3_1.xsd

这两个的版本都要是3.0+

然后在这个servlet中加入

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1	< async-supported >true</ async-supported >

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< servlet >          < servlet-name >appServlet</ servlet-name >          < servlet-class >org.springframework.web.servlet.DispatcherServlet</ servlet-class >          < init-param >              < param-name >contextConfigLocation</ param-name >              < param-value >classpath*:servlet-context.xml</ param-value >          </ init-param >          < load-on-startup >1</ load-on-startup >          < async-supported >true</ async-supported >      </ servlet >

然后所有的filter中也加入

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1	< async-supported >true</ async-supported >

3、添加相关依赖

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< dependency >              < groupId >com.fasterxml.jackson.core</ groupId >              < artifactId >jackson-annotations</ artifactId >              < version >2.3.0</ version >          </ dependency >          < dependency >              < groupId >com.fasterxml.jackson.core</ groupId >              < artifactId >jackson-core</ artifactId >              < version >2.3.1</ version >          </ dependency >          < dependency >              < groupId >com.fasterxml.jackson.core</ groupId >              < artifactId >jackson-databind</ artifactId >              < version >2.3.3</ version >          </ dependency >

好了，现在websocket可以正常建立起来了

返回用户未读的消息

当连接建立后，会进入SystemWebSocketHandler的afterConnectionEstablished方法，代码看上边，取出WebSocketHandshakeInterceptor中保存的用户名

查询信息后使用session.sendMessage(new TextMessage(count + ""));返回给用户，从哪来回哪去

服务端推送消息给用户

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@Controller public class AdminController {        static Logger logger = LoggerFactory.getLogger(AdminController. class );        @Autowired (required = false )      private AdminService adminService;        @Bean      public SystemWebSocketHandler systemWebSocketHandler() {          return new SystemWebSocketHandler();      }          @RequestMapping ( "/auditing" )      @ResponseBody      public String auditing(HttpServletRequest request){          //无关代码都省略了          int unReadNewsCount = adminService.getUnReadNews(username);          systemWebSocketHandler().sendMessageToUser(username, new TextMessage(unReadNewsCount + "" ));          return result;      } }

在这里可以使用sendMessageToUser给某个用户推送信息，也可以使用sendMessageToUsers给所有用户推送信息