在Python中通過threading模組定義和調用線程的方法，pythonthreading

在Python中通過threading模組定義和調用線程的方法，pythonthreading

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。

文法：

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，預設為Thread-N，通常使用預設即可。但伺服器端程式線程功能不同時，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模組一起使用：

#!/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建立。通過整合threading.Thread類也可以建立線程。Thread類首先完成一些基本上初始化，然後調用它的run()。run()方法會會調用傳遞給建構函式的目標函數。

#!/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