004redis与python的交互

文章目录

redis-py常用的操作指令
- 创建连接池
- 字符串类型
- 列表类型
- 集合类型
- 哈希类型
利用redis缓存学生成绩
redis事务机制
缓存观众投票数据信息案例
线程池简单案例
模拟秒杀

学习目标

掌握redis-py的连接池
掌握redis-py模板的CURD操作
掌握redis-py模块管理事务
完成具体的Redis案例

redis-py常用的操作指令

创建连接池

# -*- encoding: utf-8 -*-
"""
@File    : redis_db.py
@Time    : 2021-08-23 15:52
@Author  : XD
@Email   : gudianpai@qq.com
@Software: PyCharm
"""
import redis
try:pool = redis.ConnectionPool(host = "localhost",port = 6379,db = 0,max_connections = 20)
except Exception as e:print(e)

字符串类型

# -*- encoding: utf-8 -*-
"""
@File    : example_1.py
@Time    : 2021-08-23 15:51
@Author  : XD
@Email   : gudianpai@qq.com
@Software: PyCharm
"""
from redis_db import pool
import rediscon = redis.Redis(connection_pool = pool
)con.set("country", "英国")
con.set("city", "伦敦")
city = con.get("city").decode("utf-8")
con.expire("city", 5) #过期时间五秒钟print(city)
del  con

# -*- encoding: utf-8 -*-
"""
@File    : example_2.py
@Time    : 2021-08-23 16:28
@Author  : XD
@Email   : gudianpai@qq.com
@Software: PyCharm
"""
from redis_db import pool
import redis#获得一个连接
con = redis.Redis(connection_pool = pool
)try:con.delete("country", "city")con.mset({"country":"德国","city":"柏林"})result = con.mget("country","city")for one in result:print(one.decode("utf-8"))
except Exception as e:print(e)
finally:del con

列表类型

# -*- encoding: utf-8 -*-
"""
@File    : example_3.py
@Time    : 2021-08-23 19:19
@Author  : XD
@Email   : gudianpai@qq.com
@Software: PyCharm
"""
from redis_db import pool
import rediscon = redis.Redis(connection_pool = pool
)try:con.rpush("dname","董事会","秘书处","财务部","技术部")con.lpop("dname")result = con.lrange("dname", 0, -1)for one in result:print(one.decode("utf-8"))
except Exception as e:print(e)
finally:del con

集合类型

# -*- encoding: utf-8 -*-
"""
@File    : example_4.py
@Time    : 2021-08-23 20:14
@Author  : XD
@Email   : gudianpai@qq.com
@Software: PyCharm
"""
from redis_db import pool
import rediscon = redis.Redis(connection_pool = pool
)
try:con.sadd("employee",8001,8002,8003)con.srem("employee",8002)result = con.smembers("employee")for one in result:print(one.decode("utf-8"))con.zadd("keyword",{"马云":0,"张朝阳":0,"丁磊":0})con.zincrby("keyword",10,"马云")result = con.zrevrange("keyword",0,-1)for one in result:print(one.decode("utf-8"))
except Exception as e:print(e)
finally:del con

8001
8003
马云
张朝阳
丁磊

哈希类型

# -*- encoding: utf-8 -*-
"""
@File    : example_5.py
@Time    : 2021-08-23 20:49
@Author  : XD
@Email   : gudianpai@qq.com
@Software: PyCharm
"""
from redis_db import pool
import rediscon = redis.Redis(connection_pool = pool
)try:con.hmset("9527",{"name:":"scott","sex":"male","age":35})con.hset("9527","city","纽约")con.hdel("9527","age")result = con.hexists("9527","sex")print(result)result = con.hgetall("9527")# for one in result:#     print(one.decode("utf-8"), result[one].decode("utf-8"))for k, v in result.items():print(k.decode("utf-8"), v.decode("utf-8"))
except Exception as e:print(e)
finally:del  con

True
name: scott
sex male
city 纽约

利用redis缓存学生成绩

# -*- encoding: utf-8 -*-
"""
@File    : example_8.py
@Time    : 2021-08-24 13:49
@Author  : XD
@Email   : gudianpai@qq.com
@Software: PyCharm
"""
#练习1，从txt文档中解析学生的信息，把考试语数外成绩超过85分的同学信息缓存到哈希表中
from redis_db import pool
import rediscon = redis.Redis(connection_pool = pool
)try:file = open(file = "chengji.txt",mode = "r", encoding = "utf-8")data = file.read().splitlines()#元组for one in data:temp = one.split(",")sid = temp[0]name = temp[1]classno = temp[2]score_1 = int(temp[3])score_2 = int(temp[4])score_3 = int(temp[5])if score_1 >= 85 and score_2 >= 85 and score_3 >= 85:con.hmset(sid, {"name":name,"classno":classno,"score_1":score_1,"score_2":score_2,"score_3":score_3})except Exception as e:print(e)
finally:if "file" in dir():file.close()del  con

redis事务机制

redis事务机制为了什么？为了在并发执行时，被别的客户端的命令插队。事务机制就为了解决这个插队执行的问题。
2.为了实现数据的一致性在开启事务之前务必需要用watch命令监视要操作的记录，如果数据被别的客户端修改了则该事务关闭。满足了数据的一致性。

# -*- encoding: utf-8 -*-
"""
@File    : example_7.py
@Time    : 2021-08-24 11:35
@Author  : XD
@Email   : gudianpai@qq.com
@Software: PyCharm
"""
#redis用pipline（管道）的方式向redis服务器传递批处理命令和执行事务
from redis_db import pool
import rediscon = redis.Redis(connection_pool = pool
)try:pipline = con.pipeline()pipline.watch("9527")pipline.multi()pipline.hset("9527","name","jack")pipline.hset("9527","age",23)pipline.execute()except Exception as e:print(e)
finally:if "pipline" in dir():pipline.reset()del con

缓存观众投票数据信息案例

# -*- encoding: utf-8 -*-
"""
@File    : example_6.py
@Time    : 2021-08-23 21:05
@Author  : XD
@Email   : gudianpai@qq.com
@Software: PyCharm
"""
#用python程序模拟300位观众，为5位嘉宾随机投票，最后按照降序排列结果
from redis_db import pool
import redis
import randomcon = redis.Redis(connection_pool = pool
)try:con.delete("ballot")con.zadd("ballot",{"马云":0,"丁磊":0,"张朝阳":0,"马化腾":0,"李彦宏":0})names = ["马云","丁磊","张朝阳","马化腾","李彦宏"]for i in range(0, 300):num = random.randint(0,4)name = names[num]con.zincrby("ballot", 1 , name)result = con.zrevrange("ballot",0, -1, "WITHSCORES")#希望得到元组值和分数值要加上"WITHSCORES"for one in result:print(one[0].decode("utf-8"), int(one[1]))
except Exception as e:print(e)
finally:del con

丁磊 71
李彦宏 60
张朝阳 60
马化腾 57
马云 52

线程池简单案例

# -*- encoding: utf-8 -*-
"""
@File    : example_9.py
@Time    : 2021-08-24 16:33
@Author  : XD
@Email   : gudianpai@qq.com
@Software: PyCharm
"""
from  concurrent.futures import ThreadPoolExecutordef say_hello():print("hello")excutor = ThreadPoolExecutor(50)
for i in range(0, 10):excutor.submit(say_hello)

hello
hello
hello
hello
hello
hello
hello
hello
hello
hello

模拟秒杀

redis事务机制为了什么？为了在并发执行时，被别的客户端的命令插队。事务机制就为了解决这个插队执行的问题。为了实现数据的一致性在开启事务之前务必需要用watch命令监视要操作的记录，如果数据被别的客户端修改了则该事务关闭。满足了数据的一致性。

# -*- encoding: utf-8 -*-
"""
@File    : example_10.py
@Time    : 2021-08-24 18:14
@Author  : XD
@Email   : gudianpai@qq.com
@Software: PyCharm
"""
#利用python多线程模拟商品秒杀活动，不可以出现超买和超卖的情况，假设A商品有50件参与秒杀活动，10分钟秒杀自动结束
import redis
from redis_db import pool
import random
from concurrent.futures import ThreadPoolExecutor
#生成用户ID
id = set()
while True:if len(id) == 1000:breaknum = random.randint(10000,100000)id.add(num)con = redis.Redis(connection_pool = pool
)try:con.delete("kill_total", "kill_num", "kill_flag", "kill_user")con.set("kill_total", 50)con.set("kill_num", 0)con.set("kill_flag", 1)con.expire("kill_flag", 10)except Exception as e:print(e)
finally:del con#线程池
executor = ThreadPoolExecutor(200)def buy():connection = redis.Redis(connection_pool = pool)pipline = connection.pipeline()try:if connection.exists("kill_flag") == 1:pipline.watch("kill_num", "kill_user",)total = int(pipline.get("kill_total").decode("utf-8"))num = int(pipline.get("kill_num").decode("utf-8"))if num < total:pipline.multi()pipline.incr("kill_num")user_id = id.pop()pipline.rpush("kill_user", user_id)pipline.execute()except Exception as e:print(e)finally:if "pipline" in dir():pipline.reset()del connectionfor i in range(0, 1000):executor.submit(buy)
print("秒杀已经结束")


Watched variable changed.
Watched variable changed.
Watched variable changed.
Watched variable changed.
Watched variable changed.
Watched variable changed.
Watched variable changed.
Watched variable changed.
Watched variable changed.
Watched variable changed.
Watched variable changed.
秒杀已经结束
Too many connections
Too many connections
Too many connections
Too many connections
Too many connections

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004redis与python的交互

文章目录

redis-py常用的操作指令

创建连接池

字符串类型

列表类型

集合类型

哈希类型

利用redis缓存学生成绩

redis事务机制

缓存观众投票数据信息案例

线程池简单案例

模拟秒杀

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