多个线程有序执行

from threading import Thread,Lock
from time import sleep

class Task1(Thread):
    def run(self):
        while True:
            if lock1.acquire():
                print("------Task 1 -----")
                sleep(0.5)
                lock2.release()

class Task2(Thread):
    def run(self):
        while True:
            if lock2.acquire():
                print("------Task 2 -----")
                sleep(0.5)
                lock3.release()

class Task3(Thread):
    def run(self):
        while True:
            if lock3.acquire():
                print("------Task 3 -----")
                sleep(0.5)
                lock1.release()

#使用Lock创建出的锁默认没有“锁上”
lock1 = Lock()
#创建另外一把锁，并且“锁上”
lock2 = Lock()
lock2.acquire()
#创建另外一把锁，并且“锁上”
lock3 = Lock()
lock3.acquire()

t1 = Task1()
t2 = Task2()
t3 = Task3()

t1.start()
t2.start()
t3.start()

运行结果:

------Task 1 -----
------Task 2 -----
------Task 3 -----
------Task 1 -----
------Task 2 -----
------Task 3 -----
------Task 1 -----
------Task 2 -----
------Task 3 -----
------Task 1 -----
------Task 2 -----
------Task 3 -----
------Task 1 -----
------Task 2 -----
------Task 3 -----
...省略...

可以使用互斥锁完成多个任务，有序的进程工作，这就是线程的同步。