import paho.mqtt.client as mqtt

User = "yfkj"
Passwd = "yfkj"
HOST = "121.43.122.145"
PORT = 1883

pub = [('/zhai/test/#', 0)]

def on_message(client, userdata, msg):
    """接收到消息的回调方法"""
    print(msg.topic, msg.payload)

def on_connect(client, userdata, flags, rc):
    '''mqtt 连接成功后的回调'''
    client.subscribe(pub)
    msg = """大数据平台 MQTT 订阅:
{}
""".format('\n'.join([i[0] for i in pub]))
    print(msg)
    print('--------------')

client = mqtt.Client()
client.username_pw_set(User, Passwd)  # 必须设置，否则会返回「Connected with result code 4」
client.on_connect = on_connect
client.on_message = on_message
client.connect(HOST, PORT, 30)
client.loop_forever()