- 根据上面给出的student表,编写Python程序完成如下操作:
(1)读取student表的数据内容,将其转为JSON格式,发送给Kafka;
创建Student表的SQL语句如下:
create table student(
sno char(5),
sname char(10),
ssex char(2),
sage int
);
向student表中插入两条记录的SQL语句如下:
insert into student values(‘95001’,’John’,’M’,23);
insert into student values(‘95002’,’Tom’,’M’,23);
启动zookeeper和kafka的服务
编写一个生产者程序mysql_producer.py:
from kafka import KafkaProducer
import json
import pymysql.cursors
producer = KafkaProducer(bootstrap_servers='localhost:9092',value_serializer=lambda v:json.dumps(v).encode('utf-8'))
connect=pymysql.Connect(
host='localhost',
port=3306,
user='root',
passwd='123456',
db='zhangna',
charset='utf8'
)
cursor=connect.cursor()
sql="select sno,sname,ssex,sage from student;"
cursor.execute(sql)
data=cursor.fetchall()
connect.commit()
for message in data:
zn={}
zn['sno']=message[0]
zn['sname']=message[1]
zn['sex']=message[2]
zn['age']=message[3]
producer.send('mysql_topic',zn)
connect.close()
producer.close()
(2)再从Kafka中获取到JSON格式数据,打印出来;
编写一个消费者程序mysql_consumer.py:
from kafka import KafkaConsumer
import json
import pymysql.cursors
consumer = KafkaConsumer('mysql_topic',bootstrap_servers=['localhost:9092'],group_id=None,auto_offset_reset='earliest')
for msg in consumer:
msg1=str(msg.value,encoding="utf-8")
data=json.loads(msg1)
print(data)
终于出来了,出错的原因是encoding,我写成了encodings的缘故
为什么我会出现两条重复记录,原因是我生产者程序运行了多次,生产者多运行一次,消费者程序就会多一次查询