多线程深入理解和守护线程、子线程、锁、queue、evenet等介绍

1、多线程类的继承

import threading
import time
class MyThreading(threading.Thread):
    def __init__(self,n):
        super(MyThreading,self).__init__()
        self.n = n
    def run(self):
        print("threading %s"%(self.n))
        time.sleep(2)


threading1 = MyThreading("%s" %(1))
threading2 = MyThreading("%s" %(2))
threading1.start()
threading1.join() ## 1执行完才会执行2
threading2.start()

E:UsersxiajinqiPycharmProjectsAtmvenvScriptspython.exe E:/Users/xiajinqi/PycharmProjects/Atm/test4.py
threading 1
threading 2
。。。。。。。

2、线程测试案例

import threading
import time
class MyThreading(threading.Thread):
    def __init__(self,n):
        super(MyThreading,self).__init__()
        self.n = n
    def run(self):
        time.sleep(2)
        print("threading %s"%(self.n))



threading1 = MyThreading("%s" %(1))
threading2 = MyThreading("%s" %(2))
threading1.start()
threading1.join() ## 1执行完才会执行2
threading2.start()

print("main")

E:UsersxiajinqiPycharmProjectsAtmvenvScriptspython.exe E:/Users/xiajinqi/PycharmProjects/Atm/test4.py
threading 1
main
threading 2

3、多线程时间测试案例

import threading
import time
list = [ ]
def run(i):
    print("test %s"%(i))
    time.sleep(2)

starttime = time.time()
for i in range(1,50):
    t1 = threading.Thread(target=run,args=(i,))
    t1.start()
    list.append(t1)

for i in  list :
    i.join()

print("end")


endtime = time.time()
print("cost:", endtime-starttime)

E:UsersxiajinqiPycharmProjectsAtmvenvScriptspython.exe E:/Users/xiajinqi/PycharmProjects/Atm/test3.py
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end
cost: 2.007871150970459

Process finished with exit code 0

　4、守护线程概念，默认情况下为非守护线程，即主线程推出前，需要等待所有的非守护线程结束放可以推出。而守护线程就表示这个线程“不重要”，即主线程结束时候，无需等待守护线程是否执行完成。

import threading
import time
list = [ ]
def run(i):
    print("test %s"%(i))
    time.sleep(5)
    print("setDaemon end ")

starttime = time.time()
for i in range(1,50):
    t1 = threading.Thread(target=run,args=(i,))
#    t1.setDaemon(True)
    t1.start()
    list.append(t1)


print("main  end")
E:UsersxiajinqiPycharmProjectsAtmvenvScriptspython.exe E:/Users/xiajinqi/PycharmProjects/Atm/test3.py
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main  end
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Process finished with exit code 0



import threading
import time
list = [ ]
def run(i):
    print("test %s"%(i))
    time.sleep(5)
    print("setDaemon end ")

starttime = time.time()
for i in range(1,50):
    t1 = threading.Thread(target=run,args=(i,))
    t1.setDaemon(True)
    t1.start()
    list.append(t1)


print("main  end")


E:UsersxiajinqiPycharmProjectsAtmvenvScriptspython.exe E:/Users/xiajinqi/PycharmProjects/Atm/test3.py
test 1
test 2
test 3
test 4
test 5
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main  end

Process finished with exit code 0

 5、GIL 和线程锁。GIL就是一把全局排他锁。他的作用就是保证同一时刻只有一个线程可以执行代码,对多线程有较大影响。

import threading
import time
lock  = threading.Lock()
list = [ ]

res = 0
def run(i):
    # 在Python3.5中已经优化，结果都是50.在python2.7如果不加锁可能有一场
    lock.acquire()
    global res
    res =  res + 1
    lock.release()


starttime = time.time()
for i in range(0,50):
    t1 = threading.Thread(target=run,args=(i,))
    t1.setDaemon(True)
    t1.start()
    list.append(t1)

for i in list:
    i.join()


print(res)

 6、当有多重锁时候，可以使用Rlock,使用递归锁可以避免出现死锁的情况

7、信号量简单实用。信号量就相当于多把锁

# Author : xiajinqi
import threading
import time

semaphore = threading.BoundedSemaphore(5)

def run(i):
    semaphore.acquire()
    print("阮娇。。。。")
    time.sleep(2)
    semaphore.release()

for i  in range(1,20):
    tt = threading.Thread(target=run,args=(i,))
    tt.start()

8、event 在线程间简单应用，车子等红灯

# Author : xiajinqi
import threading
import time

event = threading.Event()

# 0 -10 绿灯 10-20红灯，大于二十从0开始
def lighter():
    count = 0
    while  True :

        if count >= 10 and count <20 :
            event.clear()
            print("当前红灯")
            count = count + 1
        elif count >=20 :
            count = 0
        else :
            event.set()
            print("当前绿灯")
            count += 1
        time.sleep(1)
def run():
    while True :
        time.sleep(1)
        if event.is_set() : #event.waite(0 如果没有值，就会一直卡主等待
            print("开始过十字路口")
        else :
            print("开始等车")
            event.wait()



t1 = threading.Thread(target=lighter)
t2 = threading.Thread(target=run)

t1.start()
t2.start()

9、队列queue和列表、元组的区别。二者都有顺序。但是从列表取一个数据，数据还存在。而队列取出一个数据以后，改数据在队列就会被清空。符合实际应用场景。队列有三种:一、先进先去 二、先进后去 三、可以设置优先级别的队

import queue

# 先进先去
qu= queue.Queue()
for i in range(1,5):
    qu.put(i)

while qu.qsize() >0:
    print(qu.get())

# 先进后去
import queue

# 先进先去
qu= queue.LifoQueue()
for i in range(1,5):
    qu.put(i)

while qu.qsize() >0:
    print(qu.get())

E:UsersxiajinqiPycharmProjectsAtmvenvScriptspython.exe E:/Users/xiajinqi/PycharmProjects/Atm/333.py
4
3
2
1

import queue

# 具有优先级别的队列 .类型需要一样
qq= queue.PriorityQueue()


list =[(1,"xiajinqi"),(1,"test"),(2,"test2"),(3,"test3"),(5,"test5"),(3,"test3")]


for lt in list:
    qq.put(lt)

while qq.qsize() >0:
    print(qq.get())

import queue

# 具有优先级别的队列 .类型需要一样
qq= queue.PriorityQueue()


list =[(1,"xiajinqi"),(1,"test"),(2,"test2"),(3,"test3"),(5,"test5"),(3,"test3")]


for lt in list:
    qq.put(lt)

while qq.qsize() >0:
    print(qq.get())

　　

10、消费者生产者模型，解耦，相互不影响

import queue
import time
import threading
qu = queue.Queue(maxsize=10)





# 每次生产十个
def Producder():
    while True:
        for i  in range(1,3):
            print("生产了两个骨头")
            qu.put("骨头 %s"%(i))
        time.sleep(2)


# 生产者消费者模型，多个人生产多个人消费。
def Consumer(name) :
    while True:
        print("%s 吃了一个骨头 %s"%(name,qu.get()))
        time.sleep(0.5)


#两个消费
c1 = threading.Thread(target=Consumer,args=("test1",))
c2 = threading.Thread(target=Consumer,args=("test2",))
pd1 = threading.Thread(target=Producder)
pd1.start()
c1.start()
c2.start()