在Python中通过threading模块定义和调用线程的方法_Python

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：

1	`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：

1	`$ ./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：

1	`$ ./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：

1	`$ ./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：

1	`$ ./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