具体代码 java
时间: 2023-07-02 13:18:54 浏览: 39
以下是一个简单的Java程序示例,用于将16进制数据转换为二进制数据,并将其发送到MQTT Broker。这里使用Eclipse Paho MQTT客户端库来实现MQTT通信。
```java
import org.eclipse.paho.client.mqttv3.*;
import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;
public class MqttSample {
public static void main(String[] args) {
String topic = "test";
String content = "1234"; // 16进制数
int qos = 0;
String broker = "tcp://mqtt.eclipse.org:1883";
String clientId = "JavaSample";
MemoryPersistence persistence = new MemoryPersistence();
try {
// 将16进制数转换为二进制数
byte[] payload = hexToBytes(content);
// 连接MQTT Broker
MqttClient mqttClient = new MqttClient(broker, clientId, persistence);
mqttClient.connect();
// 发布MQTT消息
MqttMessage message = new MqttMessage(payload);
message.setQos(qos);
mqttClient.publish(topic, message);
// 断开MQTT连接
mqttClient.disconnect();
} catch (MqttException me) {
System.out.println("reason "+me.getReasonCode());
System.out.println("msg "+me.getMessage());
System.out.println("loc "+me.getLocalizedMessage());
System.out.println("cause "+me.getCause());
System.out.println("excep "+me);
me.printStackTrace();
}
}
// 将16进制字符串转换为byte数组
public static byte[] hexToBytes(String hex) {
int len = hex.length();
byte[] data = new byte[len / 2];
for (int i = 0; i < len; i += 2) {
data[i / 2] = (byte) ((Character.digit(hex.charAt(i), 16) << 4)
+ Character.digit(hex.charAt(i+1), 16));
}
return data;
}
}
```
在上述代码中,我们将16进制字符串"1234"转换为二进制数组,并将其发布到MQTT主题"test"中。注意,如果您使用的是不同的MQTT Broker,您需要更改变量broker的值。另外,如果您需要使用用户名和密码进行MQTT连接认证,您可以在MqttConnectOptions对象中设置用户名和密码。