定義線程
最簡單的方法：使用target指定線程要執行的目標函數，再使用start()啟動。
語法：
class threading.Thread(group=None, target=None, name=None, args=(), kwargs={})group恒為None，保留未來使用。target為要執行的函數名。name為線程名，默認為Thread-N，通常使用默認即可。但服務器端程序線程功能不同時，建議命名。
#!/usr/bin/env python3# coding=utf-8import threadingdef 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()執行結果：
$ ./threading_define.py
function called by thread 0function called by thread 1function called by thread 2function called by thread 3function called by thread 4
確定當前線程
#!/usr/bin/env python3# coding=utf-8import threadingimport timedef 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()執行結果：
$ ./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模塊一起使用：
#!/usr/bin/env python3# coding=utf-8import loggingimport threadingimport timelogging.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 namew.start()w2.start()t.start()執行結果：
$ ./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
在子類中使用線程
前面我們的線程都是結構化編程的形式來創建。通過集成threading.Thread類也可以創建線程。Thread類首先完成一些基本上初始化，然后調用它的run()。run()方法會會調用傳遞給構造函數的目標函數。
#!/usr/bin/env python3# coding=utf-8import loggingimport threadingimport timeexitFlag = 0class 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 threadsthread1 = myThread(1, "Thread-1", 1)thread2 = myThread(2, "Thread-2", 2)# Start new Threadsthread1.start()thread2.start()print ("Exiting Main Thread")執行結果：
$ ./threading_subclass.py
Starting Thread-1Starting Thread-2Exiting Main ThreadThread-1: Tue Sep 15 11:03:21 2015Thread-2: Tue Sep 15 11:03:22 2015Thread-1: Tue Sep 15 11:03:22 2015Thread-1: Tue Sep 15 11:03:23 2015Thread-2: Tue Sep 15 11:03:24 2015Thread-1: Tue Sep 15 11:03:24 2015Thread-1: Tue Sep 15 11:03:25 2015Exiting Thread-1Thread-2: Tue Sep 15 11:03:26 2015Thread-2: Tue Sep 15 11:03:28 2015Thread-2: Tue Sep 15 11:03:30 2015Exiting Thread-2
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