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:\Users\xiajinqi\PycharmProjects\Atm\venv\Scripts\python.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:\Users\xiajinqi\PycharmProjects\Atm\venv\Scripts\python.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:\Users\xiajinqi\PycharmProjects\Atm\venv\Scripts\python.exe E:/Users/xiajinqi/PycharmProjects/Atm/test3.py test 1 test 2 test 3 test 4 test 5 test 6 test 7 test 8 test 9 test 10 test 11 test 12 test 13 test 14 test 15 test 16 test 17 test 18 test 19 test 20 test 21 test 22 test 23 test 24 test 25 test 26 test 27 test 28 test 29 test 30 test 31 test 32 test 33 test 34 test 35 test 36 test 37 test 38 test 39 test 40 test 41 test 42 test 43 test 44 test 45 test 46 test 47 test 48 test 49 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:\Users\xiajinqi\PycharmProjects\Atm\venv\Scripts\python.exe E:/Users/xiajinqi/PycharmProjects/Atm/test3.py test 1 test 2 test 3 test 4 test 5 test 6 test 7 test 8 test 9 test 10 test 11 test 12 test 13 test 14 test 15 test 16 test 17 test 18 test 19 test 20 test 21 test 22 test 23 test 24 test 25 test 26 test 27 test 28 test 29 test 30 test 31 test 32 test 33 test 34 test 35 test 36 test 37 test 38 test 39 test 40 test 41 test 42 test 43 test 44 test 45 test 46 test 47 test 48 test 49 main end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end setDaemon end 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:\Users\xiajinqi\PycharmProjects\Atm\venv\Scripts\python.exe E:/Users/xiajinqi/PycharmProjects/Atm/test3.py test 1 test 2 test 3 test 4 test 5 test 6 test 7 test 8 test 9 test 10 test 11 test 12 test 13 test 14 test 15 test 16 test 17 test 18 test 19 test 20 test 21 test 22 test 23 test 24 test 25 test 26 test 27 test 28 test 29 test 30 test 31 test 32 test 33 test 34 test 35 test 36 test 37 test 38 test 39 test 40 test 41 test 42 test 43 test 44 test 45 test 46 test 47 test 48 test 49 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:\Users\xiajinqi\PycharmProjects\Atm\venv\Scripts\python.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()
良禽择木而栖 贤臣择主而侍
