python 多线程之threading

一些常用函数:

start()：开始线程活动。
threading.Lock():创建锁
acquire（）：线程加锁
release（）：释放锁
threading.activeCount()：返回当前”进程”里面”线程”的个数（包含主进程）
threading.enumerate() ：返回当前运行中的Thread对象列表
threading.setDaemon()：参数设置为True的话会将线程声明为守护线程，必须在start() 方法之前设置，不设置为守护线程程序会被无限挂起。
join()方法来使得子进程运行结束后再执行父进程

个人比较喜欢创建线程类来实现多线程来个简单的例子，开2个线程，打印时间，未加锁情况

# -*- coding: UTF-8 -*-
import threading
import time
class MyThread(threading.Thread):
    def __init__(self, threadID, name, counter):
        super(MyThread, self).__init__()
        self.threadID, self.name, self.counter = threadID, name, counter

    def run(self):
        print "进程开始： " + self.name
        self.run_fun(self.name, self.counter, 3)
        print "进程退出：" + self.name

    def run_fun(self, threadName, delay, counter):
        while counter:
            time.sleep(delay)
            print "%s: %s" % (threadName, time.strftime('%Y-%m-%d %H:%M:%S',time.localtime()))
            counter -= 1

thread1 = MyThread(1, 'thread-1', 1)
thread2 = MyThread(2, 'thread-2', 2)
thread1.start()
thread2.start()
print threading.enumerate()
print "主进程退出"

结果很明显，线程1和线程2同时执行

加锁情况

# -*- coding: UTF-8 -*-
import threading
import time
class MyThread(threading.Thread):
    def __init__(self, threadID, name, counter):
        super(MyThread, self).__init__()
        self.threadID, self.name, self.counter = threadID, name, counter

    def run(self):
        print "进程开始： " + self.name
        threadLock.acquire()  # 获得锁
        self.run_fun()
        threadLock.release()  # 释放锁
        print "进程退出：" + self.name

    def run_fun(self):
        counter = 3
        while counter:
            time.sleep(self.counter)
            print "%s: %s" % (self.name, time.strftime('%Y-%m-%d %H:%M:%S',time.localtime()))
            counter -= 1

threadLock = threading.Lock()
thread1 = MyThread(1, 'thread-1', 1)
thread2 = MyThread(2, 'thread-2', 2)
thread1.start()
thread2.start()
print threading.enumerate() #显示运行的线程
print "主进程退出"

结果很明显，加锁之后，线程1执行完，线程2才会执行

来源：oschina

链接：https://my.oschina.net/u/2312447/blog/683542

标签

python

threading