Eclipse Californium CoAP库

Eclipse Californium 是一个开源的，基于Java语言实现的，符合CoAP标准的库。它提供了客户端和服务器端的CoAP实现，支持IPv4和IPv6两种网络协议。Eclipse Californium库的目标是为IoT应用提供一个轻量级的，可扩展的，安全的通信协议。它提供了许多高级功能，例如消息确认和重传，流控制，多路复用等，使得开发者可以方便地构建CoAP应用。

相关问题

Dependency 'org.eclipse.californium:scandium:3.7.0' not found

这个错误提示是指在你的项目中缺少了名为 "scandium" 的依赖包，它是由 Eclipse Foundation 开发的一个 CoAP 协议的实现库。你需要在你的项目中添加该依赖才能够解决该错误。具体的添加方式可能会因你使用的构建工具而有所不同，你可以通过在项目的构建文件中添加以下代码来添加该依赖：

Maven:

<dependency>
    <groupId>org.eclipse.californium</groupId>
    <artifactId>scandium</artifactId>
    <version>3.7.0</version>
</dependency>

Gradle:

dependencies {
    implementation 'org.eclipse.californium:scandium:3.7.0'
}

基于springboot设计的物联网平台，其实现mqtt协议、http协议、coap协议接入，示范代码中http协议部分包括发送端，订阅端，网关借口，列出代码依赖项，mqtt协议部分包括发送端，订阅端，网关借口，列出代码依赖项，coap协议部分包括发送端，订阅端，网关借口，列出代码依赖项，并提供示范代码

好的，以下是基于Spring Boot设计的物联网平台，实现MQTT、HTTP和CoAP协议接入的示范代码及其依赖项：

1. HTTP协议部分：

- 发送端：使用Spring的RestTemplate进行HTTP请求发送，依赖Spring Web和Spring Boot Starter Web模块。示范代码如下：

@Component
public class HttpSender {
    @Autowired
    private RestTemplate restTemplate;

    public void sendHttpRequest(String url, Object request) {
        restTemplate.postForEntity(url, request, String.class);
    }
}

- 订阅端：使用Spring WebFlux框架进行Web响应式编程，依赖Spring WebFlux和Spring Boot Starter WebFlux模块。示范代码如下：

@Controller
public class HttpSubscriber {
    @GetMapping(value = "/subscribe")
    public Mono<String> subscribe() {
        return Mono.just("Hello from HTTP subscriber!");
    }
}

- 网关接口：使用Spring Cloud Gateway网关进行HTTP协议转发，依赖Spring Cloud Gateway模块。示范代码如下：

spring:
  cloud:
    gateway:
      routes:
        - id: http-route
          uri: http://localhost:8080
          predicates:
            - Path=/http/**
          filters:
            - RewritePath=/http/(?<segment>.*), /$\{segment}

2. MQTT协议部分：

- 发送端：使用Eclipse Paho MQTT客户端进行MQTT协议消息发送，依赖Eclipse Paho MQTT Client库。示范代码如下：

@Component
public class MqttSender {
    @Value("${mqtt.broker}")
    private String brokerUrl;

    public void sendMessage(String topic, String message) {
        MqttClient client;
        try {
            client = new MqttClient(brokerUrl, MqttClient.generateClientId());
            client.connect();
            MqttMessage mqttMessage = new MqttMessage();
            mqttMessage.setPayload(message.getBytes());
            client.publish(topic, mqttMessage);
            client.disconnect();
        } catch (MqttException e) {
            e.printStackTrace();
        }
    }
}

- 订阅端：使用Eclipse Paho MQTT客户端进行MQTT协议消息订阅，依赖Eclipse Paho MQTT Client库。示范代码如下：

@Component
public class MqttSubscriber {
    private MqttClient client;

    @Value("${mqtt.broker}")
    private String brokerUrl;

    @PostConstruct
    public void init() {
        try {
            client = new MqttClient(brokerUrl, MqttClient.generateClientId());
            client.setCallback(new MqttCallback() {
                @Override
                public void connectionLost(Throwable throwable) {
                }

                @Override
                public void messageArrived(String topic, MqttMessage mqttMessage) throws Exception {
                    System.out.println("Received message from " + topic + ": " + mqttMessage.toString());
                }

                @Override
                public void deliveryComplete(IMqttDeliveryToken iMqttDeliveryToken) {
                }
            });
            client.connect();
        } catch (MqttException e) {
            e.printStackTrace();
        }
    }

    public void subscribe(String topic) throws MqttException {
        client.subscribe(topic);
    }
}

- 网关接口：使用Eclipse Paho MQTT客户端和Spring Integration框架实现MQTT消息和HTTP协议的相互转换，依赖Eclipse Paho MQTT Client库和Spring Integration模块。示范代码如下：

@Configuration
@EnableIntegration
public class MqttHttpGatewayConfiguration {
    @Value("${mqtt.broker}")
    private String brokerUrl;

    @Value("${mqtt.topic}")
    private String topic;

    @Bean
    public MessagingGatewaySupport mqttGateway() throws MqttException {
        MqttPahoClientFactory clientFactory = new DefaultMqttPahoClientFactory();
        ((DefaultMqttPahoClientFactory) clientFactory).setConnectionOptions(getMqttConnectOptions());
        ((DefaultMqttPahoClientFactory) clientFactory).setServerURIs(brokerUrl);

        MqttPahoMessageDrivenChannelAdapter adapter = new MqttPahoMessageDrivenChannelAdapter(
                MqttClient.generateClientId(), clientFactory, topic);
        adapter.setCompletionTimeout(5000);
        adapter.setConverter(new DefaultPahoMessageConverter());

        MessageProducerSupport messageProducer = new MessageProducerSupport() {
            @Override
            protected void handleMessageInternal(Message<?> message) {
                String payload = (String) message.getPayload();
                HttpHeaders headers = new HttpHeaders();
                headers.setContentType(MediaType.TEXT_PLAIN);
                HttpEntity<String> request = new HttpEntity<>(payload, headers);
                RestTemplate restTemplate = new RestTemplate();
                restTemplate.postForEntity("http://localhost:8080/http", request, String.class);
            }
        };

        IntegrationFlow flow = IntegrationFlows.from(adapter)
                .transform(new DefaultMqttPahoMessageConverter())
                .handle(messageProducer)
                .get();

        IntegrationFlowContext flowContext = new IntegrationFlowContext();
        flowContext.registration(flow).register();

        return flowContext.getBean("mqttGateway", MessagingGatewaySupport.class);
    }

    private MqttConnectOptions getMqttConnectOptions() {
        MqttConnectOptions options = new MqttConnectOptions();
        options.setCleanSession(true);
        options.setConnectionTimeout(10);
        return options;
    }
}

3. CoAP协议部分：

- 发送端：使用Eclipse Californium CoAP库进行CoAP协议请求发送，依赖Eclipse Californium CoAP库。示范代码如下：

@Component
public class CoapSender {
    private final CoapClient coapClient = new CoapClient();

    public void sendCoapRequest(String url, String payload) {
        coapClient.setURI(url);
        coapClient.post(payload, MediaTypeRegistry.TEXT_PLAIN);
    }
}

- 订阅端：使用Eclipse Californium CoAP库进行CoAP协议请求响应处理，依赖Eclipse Californium CoAP库。示范代码如下：

@Component
public class CoapSubscriber {
    private final CoapServer coapServer = new CoapServer();

    @PostConstruct
    public void init() {
        coapServer.add(new CoapResource("coap") {
            @Override
            public void handlePOST(CoapExchange exchange) {
                System.out.println("Received message from CoAP subscriber: " + exchange.getRequestText());
                exchange.respond("Hello from CoAP subscriber!");
            }
        });
        coapServer.start();
    }
}

- 网关接口：使用Eclipse Californium CoAP库和Spring Integration框架实现CoAP消息和HTTP协议的相互转换，依赖Eclipse Californium CoAP库和Spring Integration模块。示范代码如下：

@Configuration
@EnableIntegration
public class CoapHttpGatewayConfiguration {
    @Bean
    public CoapEndpoint coapEndpoint() {
        CoapEndpoint coapEndpoint = new CoapEndpoint();
        coapEndpoint.setAddress("127.0.0.1");
        coapEndpoint.setPort(5683);
        return coapEndpoint;
    }

    @Bean
    public CoapInboundGateway coapInboundGateway() {
        CoapInboundGateway coapInboundGateway = new CoapInboundGateway();
        coapInboundGateway.setEndpoint(coapEndpoint());
        coapInboundGateway.setRequestChannel(coapRequestChannel());
        coapInboundGateway.setRequestPayloadType(String.class);
        coapInboundGateway.setRequestTimeout(5000);
        return coapInboundGateway;
    }

    @Bean
    public MessageChannel coapRequestChannel() {
        return new DirectChannel();
    }

    @Bean
    public IntegrationFlow coapToHttpFlow() {
        return IntegrationFlows.from(coapInboundGateway())
                .transform(new ObjectToStringTransformer())
                .handle(Http.outboundChannelAdapter("http://localhost:8080/http"))
                .get();
    }
}

以上是示范代码及其依赖项，希望对您有所帮助。如有任何问题，请随时提出。