Pycharm访问 Redis 数据库

安装redis-py模块：

pip3 install redis -i https://pypi.tuna.tsinghua.edu.cn/simple some-package

1. 创建连接

创建连接对象与线程池对象，最后封装连接池：

python 复制代码

import redis
try:
    pool = redis.ConnectionPool(
        host='localhost',
        port=6379,
        #password='123456',
        db=0,
        max_connections=2000
    )
except Exception as e:
    print(e)

2.基本键值对管理

从连接池中获取连接、设置键值对、获取键值、设置键的过期时间以及删除键。

python 复制代码

from redis_db import pool
import redis
#从连接池中获取一根连接,赋值跟conn
conn = redis.Redis(connection_pool=pool)
conn.set("country","中国")
conn.set("city","沈阳")
conn.set("s.country","日本")
country = conn.get("s.country").decode("utf-8")
# 30秒后销毁日本
conn.expire("s.country",30)
print(country)
#删除数据
conn.delete("city")
#删除连接
del conn

3.操作五种数据类型

初始化Redis连接：

python 复制代码

from redis_db import pool
import redis
conn = redis.Redis(connection_pool=pool)

3.1 操作字符串

python 复制代码

#多个字符串操作
#mset必须传入字典类型的数据
conn.mset({
    "country":"中国",
    "city":"沈阳",
})
result = conn.mget("country","city")
for one in result:
    print(one.decode("utf-8"))
del conn

3.2 操作列表

python 复制代码

#列表
conn.lpush(
    "dname","董会","秘处","财部","技部"
)
result = conn.lrange("dname",0,-1)
# 随机删除
# conn.lpop("dname")
for one in result:
    print(one.decode("utf-8"))
del conn

3.3 操作集合

python 复制代码

#集合
conn.sadd("employee",8001,8002,8003)
conn.srem("employee",8002)
result = conn.smembers("employee")
for one in result:
    print(one.decode("utf-8"))
del conn

3.4 操作有序集合

python 复制代码

conn.zadd("keyword",{"Adela":0,"Hela":0,"Zoya":0})
conn.zincrby("keyword",10,"Adela")
result = conn.zrevrange("keyword",0,-1)
for one in result:
    print(one.decode("utf-8"))
del conn

3.5 操作哈希表

python 复制代码

#哈希
conn.hset("9527","ciy","北京")
result = conn.hexists("9527","name")
print(result)
result = conn.hgetall("9527")
for one in result:
    print(one.decode("utf-8"),result[one].decode("utf-8"))
del conn

4.事务函数

redis-py模块用pipeline(管道)的方式向Redis服务器传递批处理命令和执行事务

python 复制代码

# 事务控制
from redis_db import pool
import redis
conn = redis.Redis(connection_pool=pool)
try:
    pipline = conn.pipeline() # 通过管道模块实现事务控制
    pipline.watch("9527")
    pipline.multi() # 启动事务控制
    pipline.hset("9527","name1","tom")
    pipline.hset("9527","age1","33")
    pipline.execute() # 提交事务
except Exception as e:
    print(e)
    pipline.reset() #回滚
finally:
    if "pipline" in dir():
        pipline.close()

5.观众投票数据信息案例

用Python程序模拟300位观众，为5位嘉宾(马云、马明哲、张朝阳、马化腾、李彦宏)随机投票，

最后，按照降序排列结果。

python 复制代码

import random
from redis_db import pool
import redis
conn = redis.Redis(connection_pool=pool)
conn.delete("ballot")
conn.zadd("ballot", {"马云":0,"马明哲":0,"张朝阳":0,"马化腾":0,"李彦宏":0})
names =["马云","马明哲","张朝阳","马化腾","李彦宏"]
for i in range(0,300):
    num = random.randint(0,4)
    name = names[num]
    conn.zincrby("ballot",1,name)
result = conn.zrevrange("ballot",0,-1,"WITHSCORES")
for one in result:
    print(one[0].decode("utf-8"),int(one[1]))

6.使用线程池并发执行函数

这段代码将创建一个包含 20 个线程的线程池，

并提交 10 个 say_hello 函数的执行任务到线程池中。

由于线程池的大小是 20，所以这 10 个任务将并发执行，但任何时刻最多只有 20 个线程在运行。

如果 say_hello 函数执行的时间非常短，你可能会看到 "Hello World!" 被快速打印多次，具体打印顺序取决于线程的调度。

python 复制代码

from concurrent.futures.thread import ThreadPoolExecutor
def say_hello():
    print("Hello World!")
executor = ThreadPoolExecutor(20)
for i in range(0,10):
    executor.submit(say_hello)

7.模拟商品秒杀活动案例

利用Python多线程模拟商品秒杀过程，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。

python 复制代码

from concurrent.futures.thread import ThreadPoolExecutor
import random
from redis_db import pool
import redis
import threading
lock = threading.Lock()
# 1000个人的id值
s = set()
while True:
    if len(s) == 1000:
        break
    num = random.randint(1000, 10000)
    s.add(num)
# 初始化数据
try:
    conn = redis.Redis(connection_pool=pool)
    conn.delete("kill_total","kill_num","kill_flag","kill_user")
    conn.set("kill_total",50)
    conn.set("kill_num",0)
    conn.set("kill_flag",1)
    #秒杀活动，过去时长
    conn.expire("kill_flag",600)
except Exception as e:
    print(e)
finally:
    del conn
#线程池
executor = ThreadPoolExecutor(200)
#秒杀过程
def buy():
    conn = redis.Redis(connection_pool=pool)
    pipline = conn.pipeline()
    try:
        if conn.exists("kill_flag") == 1:
            #秒杀数量与用户数量满足一致性
            lock.acquire()
            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()#开启事务
                pipline.incr("kill_num")#秒杀数量+1
                user_id = s.pop()# 随机删除用户id并返回删除的值
                pipline.rpush("kill_user",user_id)#用户id追加至redis的kill_user中
                pipline.execute()
            lock.release()
    except Exception as e:
        print(e)
        pipline.reset()
    finally:
        del conn
#开启秒杀
for i in range(0,1000):
    executor.submit(buy)
print("秒杀活动结束")