背景

使用spring websocket實(shí)現(xiàn)后臺給前端推送消息

在支持websocket的瀏覽器版本上能夠正常實(shí)現(xiàn)消息的收發(fā)，現(xiàn)在使用sockjs做為不支持websocket的瀏覽器的兼容方案。

問題

瀏覽器支持websocket時(shí)：

并且后端會輸出對應(yīng)的連接成功的日志信息

當(dāng)瀏覽器不支持websocket時(shí)，使用sockjs：

發(fā)現(xiàn)握手請求發(fā)送成功了，但是并沒有握手成功，連接沒有建立起來，也沒有相關(guān)的日志信息輸出。

"/info"和"t="是sockjs自己加上去的，我原來的url是http://localhost:8081/FGMSP-ui/sockjs/websocket?uid=2131231

問題一

為什么sockjs會在我原有的url上自動(dòng)加上info的后綴和t這個(gè)參數(shù)？

另外sockjs之后還發(fā)起過很多次類似的請求，如下圖

都是在我原先的url上加了后綴和參數(shù)，這是什么原理??？

問題二

為什么我的第一次的握手請求發(fā)送顯示成功了（在調(diào)試DispatcherServlet類的doDispatch()時(shí)也看到了這個(gè)請求已經(jīng)進(jìn)來），但是沒有被interceptor和handler處理？是我的配置出錯(cuò)了嗎？

下面是我的一些代碼和配置

代碼

config

@Configuration
@EnableWebMvc
@EnableWebSocket
public class MySocketConfig extends WebMvcConfigurerAdapter implements WebSocketConfigurer {

    @Autowired
    private MySocketHandler mySocketHandler;

    @Autowired
    private MyInterceptor myInterceptor;

    @Override
    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
        registry.addHandler(mySocketHandler, "/websocket")
                .addInterceptors(myInterceptor);
        // 瀏覽器不支持websocket，使用sockjs建立連接
        registry.addHandler(new MySocketHandler(), "/sockjs/websocket/info")
                .addInterceptors(myInterceptor)
                .withSockJS();
    }

}

interceptor

public class MyInterceptor implements HandshakeInterceptor {

    @Override
    public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response,
                                   WebSocketHandler webSocketHandler, Map<String, Object> attributes) throws Exception {
//        System.out.println("Websocket:用戶[ID:" + ((ServletServerHttpRequest) request).getServletRequest().getSession(false).getAttribute("uid") + "]已經(jīng)建立連接");
        if (request instanceof ServletServerHttpRequest) {
            // 獲取請求參數(shù)，首先我們要獲取HttpServletRequest對象才能獲取請求參數(shù)；當(dāng)ServerHttpRequset的層次結(jié)構(gòu)打開后其子類可以獲取到我們想要的http對象，那么就簡單了。
            // 我這里是把獲取的請求數(shù)據(jù)綁定到session的map對象中（attributes）
            HttpServletRequest servletRequest = ((ServletServerHttpRequest) request).getServletRequest();
            String id = servletRequest.getSession().getId();
            // 標(biāo)記用戶
            String uid = servletRequest.getParameter("uid");
            attributes.put("uid", uid);
            if(uid!=null){
                attributes.put("uid", uid);
                System.out.println(String.format("websocket建立握手前：sessionId[%s],userId[%s]", id, uid));
            }else{
                return false;
            }
        }
        return true;
    }


    @Override
    public void afterHandshake(ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse, WebSocketHandler webSocketHandler, Exception e) {
        System.out.println("握手后");
    }
}

handler

public class MySocketHandler implements WebSocketHandler {

    private static final Logger logger = Logger.getLogger(MySocketHandler.class);

    // websocket連接建立
    @Override
    public void afterConnectionEstablished(WebSocketSession session) throws Exception {
        logger.info("Websocket Connection established");
        logger.info("getId:" + session.getId());
        logger.info ("getLocalAddress:" + session.getLocalAddress().toString());
        logger.info ("getUri:" + session.getUri().toString());
        session.sendMessage(new TextMessage("Server:connected OK!"));
        String uid = (String) session.getHandshakeAttributes().get("uid");
        if (SocketSessionMap.socketSession.get(uid) == null) {
            SocketSessionMap.socketSession.put(uid, session);
        }
    }

    // 消息處理
    @Override
    public void handleMessage(WebSocketSession session, WebSocketMessage<?> message) throws Exception {

    }

    // 消息傳輸錯(cuò)誤
    @Override
    public void handleTransportError(WebSocketSession session, Throwable throwable) throws Exception {
        if (session.isOpen()) {
            session.close();
        }
        // 移除Socket會話
        Iterator<Map.Entry<String, WebSocketSession>> iter = SocketSessionMap.socketSession.entrySet().iterator();
        while (iter.hasNext()) {
            ConcurrentHashMap.Entry entry = iter.next();
            if (entry.getValue() == session) {
                SocketSessionMap.socketSession.remove(entry.getKey());
                System.out.println("Socket會話已經(jīng)移除:用戶ID" + entry.getKey());
                break;
            }
        }
    }

    // websocket 連接關(guān)閉
    @Override
    public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception {
        // TODO Auto-generated method stub
        System.out.println("Websocket:" + session.getId() + "已經(jīng)關(guān)閉");
        // 移除Socket會話
        Iterator<Map.Entry<String, WebSocketSession>> iter = SocketSessionMap.socketSession.entrySet().iterator();
        while (iter.hasNext()) {
            ConcurrentHashMap.Entry entry = iter.next();
            if (entry.getValue() == session) {
                SocketSessionMap.socketSession.remove(entry.getKey());
                System.out.println("Socket會話已經(jīng)移除:用戶ID" + entry.getKey());
                break;
            }
        }

    }

    @Override
    public boolean supportsPartialMessages() {
        return false;
    }

    /**
     * 給某個(gè)用戶發(fā)送消息
     *
     * @param uid
     * @param message
     * @throws IOException
     */
    public void sendMessageToUser(String uid, TextMessage message)
            throws IOException {
        WebSocketSession session = SocketSessionMap.socketSession.get(uid);
        if (session != null && session.isOpen()) {
            session.sendMessage(message);
        }
    }

}

配置

DispatcherServlet配置

<servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:applicationContext-mvc.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    ...
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/websocket</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/sockjs/websocket/info</url-pattern>
    </servlet-mapping>
<servlet>

    <bean id="mySocketHandler" class="com.fingard.rh.msp.socket.MySocketHandler"/>

    <!-- 握手接口/攔截器 -->
    <bean id="myInterceptor" class="com.fingard.rh.msp.socket.MyInterceptor"/>

    <websocket:handlers >
        <websocket:mapping path="/websocket" handler="mySocketHandler"/>
        <websocket:handshake-interceptors>
            <ref bean="myInterceptor"/>
        </websocket:handshake-interceptors>
    </websocket:handlers>

    <!-- sockJS -->
    <websocket:handlers>
        <websocket:mapping path="/sockjs/websocket/info" handler="mySocketHandler"/>
        <websocket:handshake-interceptors>
            <ref bean="myInterceptor"/>
        </websocket:handshake-interceptors>
        <websocket:sockjs />
    </websocket:handlers>

問題一、問題二。請不吝賜教，萬分感激?。?/p>