1.开启线程
利用threading.Thread()类实例化
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11from threading import Thread
import time
def sayhi(name):
time.sleep(2)
print('%s say hello' %name)
if __name__ == '__main__':
t=Thread(target=sayhi,args=('egon',))
t.start()
print('主线程')通过继承Thread类
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15from threading import Thread
import time
class Sayhi(Thread):
def __init__(self,name):
super().__init__()
self.name = name
def run(self):
time.sleep(2)
print("%s say hello" %self.name)
if __name__ == "__main__":
t = Sayhi("egon")
t.start()
print("主线程")
join和setDaemon1
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13from threading import Thread
import time
def sayhi(name):
time.sleep(2)
print('%s say hello' %name)
if __name__ == '__main__':
t=Thread(target=sayhi,args=('egon',))
t.setDaemon(True) #设置为守护线程，主线程结束，子线程也跟着线束。
t.start()
t.join() #主线程等待子线程运行结束
print('主线程')
print(t.is_alive())
2.锁机制
同步锁
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23import time
import threading
num = 100 #设定一个共享变量
def addNum():
with lock:
global num
temp = num
time.sleep(0.1)
num = temp-1 #对此公共变量进行-1操作
thread_list = []
if __name__ == '__main__':
lock = threading.Lock() #由于同一个进程内的线程共享此进程的资源，所以不需要给每个线程传这把锁就可以直接用。
for i in range(100):
t = threading.Thread(target=addNum)
t.start()
thread_list.append(t)
for t in thread_list: #等待所有线程执行完毕
t.join()
print("result: ",num)死锁与递归锁
所谓死锁：是指两个或两个以上的进程或线程在执行过程中，因争夺资源而造成的一种互相等待的现象，若无外力作用，它们都将无法推进下去。此时称系统处于死锁状态，或系统产生了死锁。这此永远在互相等待的进程称死锁进程。
锁提供如下方法：
(1)Lock.acquire([blocking])
(2)Lock.release()
(3)threading.Lock() 加载线程的锁对象，是一个基本的锁对象，一次只能一个锁定，其余锁请求，需等待锁释放后才能获取
(4)threading.RLock() 多重锁，在同一线程中可用被多次acquire。如果使用RLock，那么acquire和release必须成对出现，
调用了n次acquire锁请求，则必须调用n次的release才能在线程中释放锁对象
无锁：1
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23#coding=utf8
import threading
import time
num = 0
def sum_num(i):
global num
time.sleep(1)
num +=i
print num
print '%s thread start!'%(time.ctime())
try:
for i in range(6):
t =threading.Thread(target=sum_num,args=(i,))
t.start()
except KeyboardInterrupt,e:
print "you stop the threading"
print '%s thread end!'%(time.ctime())
引入锁：1
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31#coding=utf8
import threading
import time
num = 0
def sum_num(i):
lock.acquire()
global num
time.sleep(1)
num +=i
print num
lock.release()
print '%s thread start!'%(time.ctime())
try:
lock=threading.Lock()
list = []
for i in range(6):
t =threading.Thread(target=sum_num,args=(i,))
list.append(t)
t.start()
for threadinglist in list:
threadinglist.join()
except KeyboardInterrupt,e:
print "you stop the threading"
print '%s thread end!'%(time.ctime())