我知道当你创建像newThread = MyThread(property)这样的类并且newthread.start()触发run()时会自动调用__init __().我正在寻找的是在线程终止之前自动调用的东西,所以我不必在每个return语句之前显式调用self.cleanUp().
class MyThread(Thread):
def __init__(self,property):
Thread.__init__(self)
self.property = property
def cleanUp(self):
# Clean up here
def run(self):
# Do some stuff
self.cleanUp() # Current work around
return
解决方法
一种方法是使Thread子类也为
context manager.这将有效地使__exit __()成为您想要触发的特殊方法.
以下显示了我的建议.注意：我重命名了您传递构造函数的属性参数,因为property是Python内置的名称.
from threading import Thread
import time
TEST_THREAD_EXCEPTION = False # change as desired
class MyThread(Thread):
def __init__(self,attribute):
Thread.__init__(self)
self.attribute = attribute
def cleanup(self):
# Clean up here
print(' cleaning up after thread')
def run(self):
if TEST_THREAD_EXCEPTION:
raise RuntimeError('OOPS!') # force exception
print(' other thread now running...')
time.sleep(2) # Do something...
def __enter__(self):
try:
self.run()
except Exception as exc:
print('Error: {} exception raised by thread'.format(exc))
raise # reraise the exception
return self
def __exit__(self,*args):
self.cleanup()
print('main thread begins execution')
with MyThread('hello') as thread:
print('doing other things in main thread while other thread is running')
print('main thread continuing...')
输出：
main thread begins execution other thread now running... doing other things in main thread while other thread is running cleaning up after thread main thread continuing on...
如果将TEST_THREAD_EXCEPTION更改为True,则不会调用cleanup(),因为线程未成功运行 – 尽管您可以根据需要更改它,但可能还需要确保它不会被调用两次.以下是上述代码在这种情况下的作用：
main thread begins execution
Error: OOPS! exception raised by thread
Traceback (most recent call last):
File "opposite_init.py",line 37,in <module>
with MyThread('hello') as thread:
File "opposite_init.py",line 27,in __enter__
self.run()
File "opposite_init.py",line 21,in run
raise RuntimeError('OOPS!') # force exception
RuntimeError: OOPS!