python threading模块

首先我们来看看threading包含那些属性和方法吧（官方文档在http://docs.python.org/library/threading.html）

就我一直不太明白的几个点开始吧

1. Condition

A factory function that returns a new condition variable object. A condition variable allows one or more threads to wait until they are notified by another thread.

Condition涉及到的几个方法acquire, release，wait，notify，

import threading, time
2 class Boy(threading.Thread):
3     def __init__(self, cond, name):
4         super(Boy, self).__init__()
5         self.cond= cond 
6         self.name= name 
7 
8     def run(self):
9         self.cond.acquire()
10        print self.name+': 嫁给我吧！？'
11        self.cond.notify()#唤醒一个挂起的线程，让hanmeimei表态
12        self.cond.wait()#释放内部所占用的琐，同时线程被挂起，直至接收到通知被唤醒或超时，等待hanmeimei回答
13  
14        print self.name+': 我单下跪，送上戒指！'
15        self.cond.notify()
16        self.cond.wait()
17 
18        print self.name+': Li太太，你的选择太明治了。'
19        self.cond.release()
20 
21 class Girl(threading.Thread):
22     def__init__(self, cond, name):
23         super(Girl, self).__init__()
24         self.cond = cond
25         self.name = name
26     def run(self):
27         self.cond.acquire() 
28         self.cond.wait()#等待Lilei求婚
29         print self.name+': 没有情调，不够浪漫，不答应'
30         self.cond.notify() 
31         self.cond.wait() 
32 
33 
34         print self.name +': 好吧，答应你了'
35         self.cond.notify() 
36         self.cond.release() 
37 
38 cond = threading.Condition()
39 boy = Boy(cond, 'LiLei')
40 girl = Girl(cond, 'HanMeiMei')
41 girl.start()
42 boy.start()

运行结果是

LiLei: 嫁给我吧！？
HanMeiMei: 没有情调，不够浪漫，不答应
LiLei: 我单下跪，送上戒指！
HanMeiMei: 好吧，答应你了
LiLei: Li太太，你的选择太明治了。

2. Event

A factory function that returns a new event object. An event manages a flag that can be set to true with theset() method and reset to false with theclear() method. Thewait() method blocks until the flag is true.

个人任务Event是个简易的Condition，还是用上面求婚做哥例子吧

 

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import threading, time

class Boy(threading.Thread):

    def__init__(self, cond, name):

        super(Boy,self).__init__()

        self.cond= cond

        self.name= name

    defrun(self):

        printself.name +': 嫁给我吧！？'

        self.cond.set()#唤醒一个挂起的线程，让hanmeimei表态

        time.sleep(0.5)

        self.cond.wait()

        printself.name +': 我单下跪，送上戒指！'

        self.cond.set()

        time.sleep(0.5)

        self.cond.wait()

        self.cond.clear()

        printself.name +': Li太太，你的选择太明治了。'

classGirl(threading.Thread):

    def__init__(self, cond, name):

        super(Girl,self).__init__()

        self.cond= cond

        self.name= name

    defrun(self):

        self.cond.wait()#等待Lilei求婚

        self.cond.clear()

        printself.name +': 没有情调，不够浪漫，不答应'

        self.cond.set()

        time.sleep(0.5)

        self.cond.wait()

        printself.name +': 好吧，答应你了'

        self.cond.set()

 

cond =threading.Event()

boy =Boy(cond, 'LiLei')

girl =Girl(cond, 'HanMeiMei')

boy.start()

girl.start()

 

 

 

3. Lock

A primitive lock is a synchronization primitive that is not owned by a particular thread when locked. In Python, it is currently the lowest level synchronization primitive available, implemented directly by thethread extension module.

4. RLock

A reentrant lock is a synchronization primitive that may be acquired multiple times by the same thread. Internally, it uses the concepts of “owning thread” and “recursion level” in addition to the locked/unlocked state used by primitive locks. In the locked state, some thread owns the lock; in the unlocked state, no thread owns it.

这两种琐的主要区别是：RLock允许在同一线程中被多次acquire。而Lock却不允许这种情况。注意：如果使用RLock，那么acquire和release必须成对出现，即调用了n次acquire，必须调用n次的release才能真正释放所占用的琐。

5. Thread

上面的例子也很清楚，

join

主调线程堵塞，直到被调用线程运行结束或超时.

daemon(文档上这么写的，不理解)

布尔值。True表示为守护线程。该线程的设置必须在start()之前。初始值从你线程继承而来，主线程为非daemon线程。

对于共享数据的同步问题，我们选两个比较常用的方法来解决。

6. Timer

比较简单直观

def hello():
2     print"hello, world"
3     t = Timer(3, hello)
4     t.start()

剩下的一些threading的方法比较好理解currentThread，activeCount，enumerate