Python学习06--多线程之线程同步、通信

1.线程同步

<1>简单的线程同步使用

使用Thread对象的Lock和RLock可以事先简单的线程同步，RLock和Lock偶具有acquire方法和release方法

'''
Created on 2015-1-7

@author: huangpeng03
'''
import threading
import time

x =0
class mythread(threading.Thread):
    def __init__(self,threadname):
        threading.Thread.__init__(self,name=threadname)

    def run(self):
        global x
        lock.acquire()
        for i in range(3):
            x = x+1
        time.sleep(2)
        print x
        lock.release()

if __name__ == '__main__':
    lock = threading.RLock()
    t1 = []
    for i in range(10):
        t = mythread(str(i))
        t1.append(t)

    for i in t1:
        i.start()

结果：每隔2s打印一次

3
6
9
12
15
18
21
24
27
30

<2>使用条件变量保持线程同步

python的Condition对象提供了对复杂线程同步的支持，使用Condition对象可以在某县时间出发后才处理数据

Condition对象除了具有acquire方法和release方法以外，还有wait、notify、notifyAll等方法用于条件处理

'''
Created on 2015-1-8

@author: huangpeng03
'''
import threading
class Producer(threading.Thread):
    def __init__(self,threadname):
        threading.Thread.__init__(self,name = threadname)
    def run(self):
        global x
        con.acquire()
        if x == 1000000:
            con.wait()
            pass
        else:
            for i in range(1000000):
                x = x+1
            con.notify()
        print x
        con.release()


class Consumer(threading.Thread):
    def __init__(self,threadname):
        threading.Thread.__init__(self)
    def run(self):
        global x
        con.acquire()
        if x == 0:
            con.wait()
            pass
        else:
            for i in range(1000000):
                x = x-1
                con.notify()
        print x
        con.release()

x = 0
if __name__ == '__main__':
    con = threading.Condition()
    p = Producer('Producer')
    c = Consumer('Consumer')
    p.start()
    c.start()
    p.join()
    c.join()
    print x

结果;

1000000
0
0