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()

------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...