spring-websocket-4.2.1应用

最新推荐文章于 2024-04-16 10:07:59 发布

原创最新推荐文章于 2024-04-16 10:07:59 发布 · 125 阅读

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CC 4.0 BY-SA版权

文章标签：

#websocket #spring #java

本文介绍了如何在前端和后端实现WebSocket连接，包括前端的建立和关闭连接的函数，后端的拦截器创建，配置文件设置以及消息处理类的详细方法，如连接建立、关闭、数据传输和异常处理。

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本文参考：https://blog.youkuaiyun.com/fffvdgjvbsfkb123456/article/details/116465394

1.前端建立连接
注：前端不用单独引用额外的js组件，websocket是浏览器自带的组件，可以直接使用。

webSocketConnect: function (orderId) {
            var host = window.location.host;
            if ("WebSocket" in window) {
                // 打开一个 web socket
                ws = new WebSocket("ws://" + host + "/上下文/webSocketHandler?id=" + orderId);
                ws.onmessage = function (evt) {
                    var received_msg = evt.data;
                    if("2"===received_msg){
                        $("#lose").show();
                    }
                };
                ws.onclose = function () {
                    // 关闭 websocket
                    console.log("连接已关闭");
                };
            } else {
                // 浏览器不支持 WebSocket
                layer.alert('不支持的浏览器！', {icon: 1});
            }
        },

2.关闭连接

closeWs: function () {
            if (ws !== null) {
                ws.close();
            }
        }

3.创建拦截器

public class WebSocketInterceptor extends HttpSessionHandshakeInterceptor {

    @Override
    public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Map<String, Object> attributes) throws Exception {
        if (request instanceof ServletServerHttpRequest) {
            ServletServerHttpRequest serverHttpRequest = (ServletServerHttpRequest) request;
            // 获取参数
            String id = serverHttpRequest.getServletRequest().getParameter("id");
            attributes.put("currentId", id);
        }
        return true;
    }

    // 初次握手访问后
    @Override
    public void afterHandshake(ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse, WebSocketHandler webSocketHandler, Exception e) {

    }
}

4.配置文件

@Configuration
@EnableWebSocket
public class WebSocketConfig  implements WebSocketConfigurer {

    @Override
    public void registerWebSocketHandlers(WebSocketHandlerRegistry webSocketHandlerRegistry) {
        webSocketHandlerRegistry.addHandler(myHandler(),"/webSocketHandler").addInterceptors(new WebSocketInterceptor());
    }

    public WebSocketHandler myHandler(){
        return new MessageHandler();
    }
}

5.处理类

public class MessageHandler implements WebSocketHandler {

    private static final Logger log = LoggerFactory.getLogger(MessageHandler.class);
    /**
     * WEB_SOCKET_MAP:使用线程安全map存储用户连接webscoket信息
     */
    private final static Map<String, WebSocketSession> WEB_SOCKET_MAP = new ConcurrentHashMap<String, WebSocketSession>();

    /**
     * 关闭websocket时调用该方法
     */
    @Override
    public void afterConnectionClosed(WebSocketSession session, CloseStatus status) throws Exception {
        String id = this.getId(session);
        if (StringUtils.isNoneBlank(id)) {
            WEB_SOCKET_MAP.remove(id);
            log.info(id + "已成功关闭");
        } else {
            log.info("关闭时，获取用户id为空");
        }

    }

    /**
     * 建立websocket连接时调用该方法
     */
    @Override
    public void afterConnectionEstablished(WebSocketSession session) throws Exception {
        String id = this.getId(session);
        if (StringUtils.isNoneBlank(id)) {
            WEB_SOCKET_MAP.put(id, session);
            session.sendMessage(new TextMessage("建立服务端连接成功！"));
        }

    }

    /**
     * 客户端调用websocket.send时候，会调用该方法,进行数据通信
     */
    @Override
    public void handleMessage(WebSocketSession session, WebSocketMessage<?> message) throws Exception {
        String msg = message.toString();
        String id = this.getId(session);
        log.info(id + "发送的消息是：" + msg);
        message = new TextMessage("服务端已经接收到消息，msg=" + msg);
        session.sendMessage(message);
    }

    /**
     * 传输过程出现异常时，调用该方法
     */
    @Override
    public void handleTransportError(WebSocketSession session, Throwable e) throws Exception {
        WebSocketMessage<String> message = new TextMessage("异常信息：" + e.getMessage());
        session.sendMessage(message);
    }

    /**
     * org.springframework.web.socket.WebSocketHandler#supportsPartialMessages()
     */
    @Override
    public boolean supportsPartialMessages() {
        return false;
    }

    /**
     * sendMessageToUser:发给指定用户
     */
    public void sendMessageToUser(String id, String contents) {
        WebSocketSession session = WEB_SOCKET_MAP.get(id);
        if (session != null && session.isOpen()) {
            try {
                TextMessage message = new TextMessage(contents);
                session.sendMessage(message);
            } catch (Exception e) {
               log.error("sendMessageToUser异常："+"id="+id+",contents="+"contents",e);
            }
        }
    }

    /**
     * sendMessageToAllUsers:发给所有的用户
     */
    public void sendMessageToAllUsers(String contents) {
        Set<String> ids = WEB_SOCKET_MAP.keySet();
        for (String id : ids) {
            this.sendMessageToUser(id, contents);
        }
    }

    /**
     * getUserId:获取用户id
     *
     * @param session
     */
    private String getId(WebSocketSession session) {
        try {
            String id = (String) session.getAttributes().get("currentId");
            return id;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
}