后浪小萌新Python --- Lock

一、数据冲突

一般发生在多个线程对同一个数据进行操作的时候

注意: Queue对象本身就是线程安全的，不会出现数据冲突

举例：

from threading import Thread data = 0 def up_data(): global data for _ in range(100008): data += 1 def down_data(): global data for _ in range(100000): data -= 1 if __name__ == '__main__': # 情况1: 在一个线程中对同一个数据进行加和减的操作 # up_data() # down_data() # print(data) # 情况2：在两个线程中进行加和减操作 t1 = Thread(target=up_data) t2 = Thread(target=down_data) t1.start() t2.start() t1.join() t2.join() print(data)

执行结果:

8

二、手动Lock

Lock - 锁类， 传统锁，重量级锁（加锁和解锁需要手动进行）

举例：

from threading import Thread, Lock data = 0 # 1.创建锁对象(有多少个数据就创建多个锁) data_lock = Lock() def up_data(): global data for _ in range(100008): # 2.加锁 data_lock.acquire() data += 1 # 3.解锁 data_lock.release() def down_data(): global data for _ in range(100000): data_lock.acquire() data -= 1 data_lock.release() if __name__ == '__main__': t1 = Thread(target=up_data) t2 = Thread(target=down_data) t1.start() t2.start() t1.join() t2.join() print(data)

执行结果:

8

三、自动锁RLock

举例：

from threading import Thread, RLock data = 0 data_lock = RLock() def up_data(): global data for _ in range(100008): # 使用锁（会自动加锁和解锁） with data_lock: data += 1 def down_data(): global data for _ in range(100000): with data_lock: data -= 1 if __name__ == '__main__': t1 = Thread(target=up_data) t2 = Thread(target=down_data) t1.start() t2.start() t1.join() t2.join() print(data)

执行结果:

8