python:线程，线程锁，线程递归锁，信号量

#!usr/bin/env python
# -*- coding:utf-8 -*-

__author__ = "Samson"

import threading,time
def run(n):
    print("task", n)
    time.sleep(2)
    print("current thread:",threading.current_thread())#当前线程

t_obj = []#存线程实例
start_time = time.time()
for i in range(50):
    t = threading.Thread(target=run,args=("t%s" %i,))
    #t.setDaemon(True)#把当前线程设置为守护线程，必须在t.start()之前设置，作用为主线程将不会等待该子线程结束
    t.start()
    t_obj.append(t)
print("total thread:",threading.active_count())#总线程数
for t in t_obj:
    t.join()#等待线程执行完
print("%s" %(abs(start_time-time.time())))

线程锁

#!usr/bin/env python
# -*- coding:utf-8 -*-

__author__ = "Samson"

import threading,time
def run(n):
    lock.acquire()#锁上
    global num
    num += 1
    #time.sleep(1)#会变为单线程
    lock.release()#解锁
lock = threading.Lock()#创建锁
num = 0
t_obj = []#存线程实例
for i in range(50):
    t = threading.Thread(target=run,args=("t%s" %i,))
    t.start()
    t_obj.append(t)
for t in t_obj:
    t.join()
print("%s" %num)

线程递归锁

#!usr/bin/env python
# -*- coding:utf-8 -*-

__author__ = "Samson"

import threading,time
def run():
    lock.acquire()#锁上
    res = run1()
    res2 = run2()
    lock.release()#解锁
def run1():
    lock.acquire()#锁上
    global num
    num += 1
    lock.release()#解锁
def run2():
    lock.acquire()#锁上
    global num
    num += 1
    lock.release()#解锁
lock = threading.RLock()#创建递归锁
num = 0
for i in range(10):
    t = threading.Thread(target=run)
    t.start()
print("Now:",threading.active_count())
while threading.active_count() != 1:
    print(threading.active_count())
else:
    print("%s" %num)

信号量

#!usr/bin/env python
# -*- coding:utf-8 -*-

__author__ = "Samson"

import threading,time
def run(n):
    semaphore.acquire()
    time.sleep(1)
    print("current thread:",n)
    semaphore.release()
if __name__ == "__main__":
    semaphore = threading.BoundedSemaphore(5)#信号量为5，表示最多允许5个线程同时执行
    for i in range(22):
        t = threading.Thread(target=run,args=(i,))
        t.start()
while threading.active_count() != 1:
    pass
else:
    print("All threads done1")

线程之Event事件模仿红绿灯

#!usr/bin/env python
# -*- coding:utf-8 -*-

__author__ = "Samson"

import time
import threading

event = threading.Event()

def lighter():
    count = 0
    event.set()
    while True:
        if count <20 and count >10:#变成红灯
            event.clear()
            print("33[41;1mred light is on...33[0m")
        elif count >20:#变成绿灯
            event.set()
            count = 0
        else:
            print("33[42;1mgreen light is on...33[0m")
        time.sleep(1)
        count += 1

def car(name):
    while True:
        if event.is_set():#设置了标志位，代表绿灯
            print("[%s] running..."% name)
            time.sleep(1)
        else:
            print("[%s] sees red light,waiting..."% name)
            event.wait()
            print("33[34;1m[%s] green ligth is on,start going...33[0m")

light = threading.Thread(target=lighter,)
light.start()

car1 = threading.Thread(target=car,args=("car1",))
car1.start()