SpringBoot3.x 和 WebSocket 在物联网设备管理中的应用

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;

@Configuration
public class WebSocketConfig {
    @Bean
    public ServerEndpointExporter serverEndpointExporter() {
        return new ServerEndpointExporter();
    }
}

import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketSession;
import org.springframework.web.socket.handler.TextWebSocketHandler;

public class DeviceMessageHandler extends TextWebSocketHandler {
    // 定义一个 WebSocketSession 的集合，用于保存连接的设备
    private Map<String, WebSocketSession> sessions = new ConcurrentHashMap<>();

    @Override
    public void afterConnectionEstablished(WebSocketSession session) throws Exception {
        // 连接建立后，将设备添加到设备集合中
        String deviceId = (String)session.getAttributes().get("deviceId");
        sessions.put(deviceId, session);
    }

    @Override
    public void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
        // 解析设备发送的消息，可能是设备状态更新，也可能是设备响应的命令执行结果
        String payload = message.getPayload();
        // 例如，我们可以将这个 payload 转换为一个 JSON 对象，然后根据 JSON 的内容处理这个消息

        // 这里以服务器回发消息作为演示
        session.sendMessage(new TextMessage("服务器已收到你的消息，消息内容：" + payload));
    }

    @Override
    public void afterConnectionClosed(WebSocketSession session, CloseStatus status) throws Exception {
        // 设备断开连接后，将设备从设备集合中移除
        String deviceId = (String)session.getAttributes().get("deviceId");
        sessions.remove(deviceId);
    }

    @Override
    public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {
        // 如果出现错误，打印一些调试信息
        exception.printStackTrace();
    }

    // 向指定设备发送消息的方法
    public void sendMessageTo(String deviceId, String message) throws IOException {
        WebSocketSession session = sessions.get(deviceId);
        if (session != null && session.isOpen()) {
            session.sendMessage(new TextMessage(message));
        }
    }
}

import org.springframework.stereotype.Component;
import org.springframework.web.socket.server.standard.SpringConfigurator;

@ServerEndpoint(value = "/device", configurator = SpringConfigurator.class)
@Component
public class DeviceServer extends DeviceMessageHandler {
    // 这里我们使用 DeviceMessageHandler 作为 WebSocket 的服务端类，它将自动处理 WebSocket 相关的事件
}

@Override
public void afterConnectionEstablished(WebSocketSession session) throws Exception {
    // 连接建立后，将设备ID 为 "device_001" 的设备添加到设备集合中
    String deviceId = "device_001";
    sessions.put(deviceId, session);

    // 向设备发送欢迎信息
    session.sendMessage(new TextMessage("欢迎设备：" + deviceId));
}

@Override
public void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {

    String payload = message.getPayload();
    JSONObject jsonPayload = new JSONObject(payload);
    String deviceId = jsonPayload.getString("deviceId");
    String status = jsonPayload.getString("status");

    // 将设备状态保存到数据库
    updateDeviceStatusInDatabase(deviceId, status);

    // 根据设备状态决定是否需要告警
    if (status.equals("warning")) {
        generateAlarm(deviceId);
    }
}

@RequestMapping(value = "/controlDevice", method = RequestMethod.POST)
public void controlDevice(@RequestParam String deviceId, @RequestParam String command) {

    DeviceMessageHandler handler = applicationContext.getBean(DeviceMessageHandler.class);

    try {
        handler.sendMessageTo(deviceId, command);
    } catch (IOException e) {
        e.printStackTrace();
    }
}