【开发技巧】-- 实现websocket实现即时消息推送（后端基于SpringBoot实现）

桃扇骨 2023-07-03 15:26 11阅读 0赞

### 1. 什么是WebSocket？ ###

websocket是HTML5中的即时通信解决方案，它使用客户端与服务器端的数据交互变得更加简单。

### 2. 如何使用websocket ###

使用websocket需要在客户端（网页中）编写相关客户端实现，然后还需要一个websocket后端服务实现。

###### 2.1 html websocket客户端实现 ######

编写好以上代码客户端就实现成功了

###### 2.2 websocket后端服务实现 ######

###### 2.2.1 在SpringBoot工程中导入相关Maven依赖 ######

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

###### 2.2.2 因为使用的是内嵌tomcat容器所以需要编写一个配置类 ######

package com.qingyun.wechat_ordersys.config;
    
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.web.socket.server.standard.ServerEndpointExporter;
    
    
    /** * Created with IntelliJ IDEA. * User: 李敷斌. * Date: 2020-02-05 * Time: 19:57 * Explain: websocket配置类 */
    @Configuration
    public class WebSocketConfig { 
    
    
        @Bean
        public ServerEndpointExporter serverEndpointExporter(){ 
            return new ServerEndpointExporter();
        }
    }

###### 2.2.3 编写后端websocket服务实现类,这里需要使用注解指定服务器的访问路径`@ServerEndpoint(value = "/websocket/server")`这个路径需要与客户端一一对应 ######

package com.qingyun.wechat_ordersys.server;
    
    import com.qingyun.wechat_ordersys.config.MySpringConfigurator;
    import lombok.extern.slf4j.Slf4j;
    import org.springframework.stereotype.Component;
    
    import javax.websocket.OnClose;
    import javax.websocket.OnMessage;
    import javax.websocket.OnOpen;
    import javax.websocket.Session;
    import javax.websocket.server.ServerEndpoint;
    import java.util.concurrent.CopyOnWriteArraySet;
    
    /** * Created with IntelliJ IDEA. * User: 李敷斌. * Date: 2020-02-05 * Time: 19:58 * Explain: websocket服务端 */
    @ServerEndpoint(value = "/websocket/server")
    @Component
    @Slf4j
    public class WebSocketServer { 
    
        //会话对象
        private Session session;
    
        //定义一个容器保存session
        private static CopyOnWriteArraySet<WebSocketServer> webSockets=new CopyOnWriteArraySet<>();
    
        @OnOpen
        public void onOpen(Session session){ 
            this.session=session;
            webSockets.add(this);
    
            log.info("【websocket消息】有新的连接，当前总连接数为：{}",webSockets.size());
        }
    
        @OnClose
        public void onClose(){ 
            //在缓存中移除当前连接
            webSockets.remove(this);
    
            log.info("【websocket消息】连接已断开，当前总连接数为：{}",webSockets.size());
        }
    
        @OnMessage
        public void onMessage(String msg){ 
            log.info("【websocket消息】收到客户端发来的消息：{}",msg);
        }
    
    
        public void sendMsg(String msg){ 
            webSockets.forEach(websocket->{ 
                log.info("【websocket消息】广播消息，msg={}",msg);
    
                try { 
                    websocket.session.getBasicRemote().sendText(msg);
                }catch (Exception e){ 
                    log.error("websocket异常");
                }
            });
        }
    }

###### 2.2.4 创建一个类用户约定并构建返回数据的格式 ######

package com.qingyun.wechat_ordersys.vo;
    
    import lombok.Data;
    
    /** * Created with IntelliJ IDEA. * User: 李敷斌. * Date: 2020-02-05 * Time: 20:06 * Explain: websocket消息vo类 */
    @Data
    public class WebSocketVO<T> { 
    
        private String msg;
    
        private String href;
    
        private T data;
    
        public WebSocketVO(String msg, String href) { 
            this.msg = msg;
            this.href = href;
        }
    
        public WebSocketVO(String msg, String href, T data) { 
            this.msg = msg;
            this.href = href;
            this.data = data;
        }
    
        public WebSocketVO(String msg) { 
            this.msg = msg;
        }
    }

###### 2.2.5 调用方法服务端推送消息给客户端 ######

@Autowired
        private WebSocketServer webSocketServer;
    
        @Autowired
        private ProjectUrlConfig projectUrlConfig;
    
        /** * 创建订单 * * @param orderDTO * @return 订单主实例 */
        @Override
        @Transactional
        public OrderDTO createOrder(OrderDTO orderDTO) { 
            /* 业务实现代码 */
    
            //向卖家端发送websocket消息
            webSocketServer.sendMsg(JSON.toJSONString(
                    new WebSocketVO<String>("你有新的订单",
                            projectUrlConfig.getLocal()+"/sell/seller/order/detail?orderId="+master.getOrderId())));
    
            return orderDTO;
        }

到此该功能就实现完毕了