Python多线程-线程锁

多线程修改一份数据时需要用到线程锁，以防止数据修改出错

#-*- coding:utf-8 -*-
__author__ = "MuT6 Sch01aR"

import threading
import time

num = 0
t_obj = []
lock = threading.Lock() #声明一个锁并赋给一个变量

def MyThread(n):
    lock.acquire() #给线程加锁
    global num
    time.sleep(0.5)
    num +=1
    lock.release() #释放给线程锁

for i in range(20):
    t = threading.Thread(target=MyThread,args=(i,))
    t.start()
    t_obj.append(t)

for t in t_obj:
    t.join()

print("num:",num)

递归锁

递归锁就是锁中有锁，一把锁套着一把锁

# -*- coding:utf-8 -*-
__author__ = "MuT6 Sch01aR"

import threading

num = 0
num2 = 0
lock = threading.RLock() #声明一个递归锁

def Lock_1():
    print("---This is Lock_1---")
    lock.acquire()
    global num
    num += 1
    lock.release()
    return num

def Lock_2():
    print("---This is Lock_2---")
    lock.acquire()
    global num2
    num2 += 1
    lock.release()
    return num2

def Lock_3():
    lock.acquire()
    print("---This is Lock_3---")
    Run_Lock_1 = Lock_1()
    print("---Between Lock_1 and Lock_2---")
    Run_Lock_2 = Lock_2()
    lock.release()
    print(Run_Lock_1,Run_Lock_2)

for i in range(10):
    t = threading.Thread(target=Lock_3)
    t.start()

while threading.active_count() != 1:
    print(threading.active_count())
else:
    print("---All Thread Have Done---")
    print(num,num2)