• 160601、Websocet服务端实现


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    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(newWebSocketHandshakeInterceptor());
     
            registry.addHandler(systemWebSocketHandler(), "/sockjs/webSocketServer").addInterceptors(newWebSocketHandshakeInterceptor())
                    .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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    <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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    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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    <script type="text/javascript" src="http://localhost:8080/Origami/websocket/sockjs-0.3.min.js"></script>
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    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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    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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    <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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    <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

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  • 原文地址:https://www.cnblogs.com/zrbfree/p/5549621.html
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