定义线程
最简单的方法：使用target指定线程要执行的目标函数，再使用start()启动。
语法：
class threading.Thread(group=None, target=None, name=None, args=(), kwargs={})
group恒为None，保留未来使用。target为要执行的函数名。name为线程名，默认为Thread-N，通常使用默认即可。但服务器端程序线程功能不同时，建议命名。
#!/usr/bin/env python3 # coding=utf-8 import threading def function(i): print ("function called by thread {0}".format(i)) threads = [] for i in range(5): t = threading.Thread(target=function , args=(i,)) threads.append(t) t.start() t.join()
执行结果：
$ ./threading_define.py
function called by thread 0 function called by thread 1 function called by thread 2 function called by thread 3 function called by thread 4
确定当前线程
#!/usr/bin/env python3 # coding=utf-8 import threading import time def first_function(): print (threading.currentThread().getName()+ str(' is Starting n')) time.sleep(3) print (threading.currentThread().getName()+ str( ' is Exiting n')) def second_function(): print (threading.currentThread().getName()+ str(' is Starting n')) time.sleep(2) print (threading.currentThread().getName()+ str( ' is Exiting n')) def third_function(): print (threading.currentThread().getName()+ str(' is Starting n')) time.sleep(1) print (threading.currentThread().getName()+ str( ' is Exiting n')) if __name__ == "__main__": t1 = threading.Thread(name='first_function', target=first_function) t2 = threading.Thread(name='second_function', target=second_function) t3 = threading.Thread(name='third_function',target=third_function) t1.start() t2.start() t3.start()
执行结果：
$ ./threading_name.py
first_function is Starting second_function is Starting third_function is Starting third_function is Exiting second_function is Exiting first_function is Exiting
配合logging模块一起使用：
#!/usr/bin/env python3 # coding=utf-8 import logging import threading import time logging.basicConfig( level=logging.DEBUG, format='[%(levelname)s] (%(threadName)-10s) %(message)s', ) def worker(): logging.debug('Starting') time.sleep(2) logging.debug('Exiting') def my_service(): logging.debug('Starting') time.sleep(3) logging.debug('Exiting') t = threading.Thread(name='my_service', target=my_service) w = threading.Thread(name='worker', target=worker) w2 = threading.Thread(target=worker) # use default name w.start() w2.start() t.start()
执行结果：
$ ./threading_names_log.py[DEBUG] (worker ) Starting
[DEBUG] (Thread-1 ) Starting [DEBUG] (my_service) Starting [DEBUG] (worker ) Exiting [DEBUG] (Thread-1 ) Exiting [DEBUG] (my_service) Exiting
在子类中使用线程
前面我们的线程都是结构化编程的形式来创建。通过集成threading.Thread类也可以创建线程。Thread类首先完成一些基本上初始化，然后调用它的run()。run()方法会会调用传递给构造函数的目标函数。
#!/usr/bin/env python3 # coding=utf-8 import logging import threading import time exitFlag = 0 class myThread (threading.Thread): def __init__(self, threadID, name, counter): threading.Thread.__init__(self) self.threadID = threadID self.name = name self.counter = counter def run(self): print ("Starting " + self.name) print_time(self.name, self.counter, 5) print ("Exiting " + self.name) def print_time(threadName, delay, counter): while counter: if exitFlag: thread.exit() time.sleep(delay) print ("%s: %s" %(threadName, time.ctime(time.time()))) counter -= 1 # Create new threads thread1 = myThread(1, "Thread-1", 1) thread2 = myThread(2, "Thread-2", 2) # Start new Threads thread1.start() thread2.start() print ("Exiting Main Thread")
执行结果：
$ ./threading_subclass.py
Starting Thread-1 Starting Thread-2 Exiting Main Thread Thread-1: Tue Sep 15 11:03:21 2015 Thread-2: Tue Sep 15 11:03:22 2015 Thread-1: Tue Sep 15 11:03:22 2015 Thread-1: Tue Sep 15 11:03:23 2015 Thread-2: Tue Sep 15 11:03:24 2015 Thread-1: Tue Sep 15 11:03:24 2015 Thread-1: Tue Sep 15 11:03:25 2015 Exiting Thread-1 Thread-2: Tue Sep 15 11:03:26 2015 Thread-2: Tue Sep 15 11:03:28 2015 Thread-2: Tue Sep 15 11:03:30 2015 Exiting Thread-2
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