python mqtt 示例代码
时间: 2024-06-24 13:01:38 浏览: 7
在Python中,使用Paho MQTT库来编写客户端程序是非常常见的,Paho是一个Python版的MQTT客户端实现。以下是一个简单的Python MQTT示例代码,展示了如何连接到MQTT broker,订阅主题并接收消息:
```python
# 导入必要的库
import paho.mqtt.client as mqtt
# 定义回调函数
def on_connect(client, userdata, flags, rc):
if rc == 0:
print("Connected to MQTT Broker!")
client.subscribe("your/topic") # 订阅主题
else:
print("Failed to connect, error code:", rc)
def on_message(client, userdata, msg):
print(f"Received message on topic: {msg.topic}")
print(f"Message payload: {msg.payload.decode('utf-8')}")
# 创建MQTT客户端
client = mqtt.Client()
# 设置回调函数
client.on_connect = on_connect
client.on_message = on_message
# 连接到MQTT服务器(请替换为实际地址)
broker_address = "your_broker_address"
port = 1883 # 默认MQTT端口
client.connect(broker_address, port)
# 开始监听消息
client.loop_forever()
```
在这个例子中,你需要将`"your/topic"`替换为你想要订阅的实际主题,同样也需要将`"your_broker_address"`替换为你的MQTT broker的地址。