Queue 对象实现一个 fifo 队列(其他的还有 lifo、priority 队列,这里不再介绍)。
queue 只有 maxsize 一个构造参数,用来指定队列容量,指定为 0 的时候代表容量无限。
主要有以下成员函数:
Queue.qsize():返回消息队列的当前空间。返回的值不一定可靠。
Queue.empty():判断消息队列是否为空,返回 True 或 False。同样不可靠。
Queue.not_empty():判断消息队列是否为非空。同上不可靠。
Queue.full():类似上边,判断消息队列是否满。
Queue.put(item, block=True, timeout=None):往消息队列中存放消息。block 可以控制是否阻塞,timeout 指定阻塞时候的等待时间。如果不阻塞或者超时,会引起一个 full exception。
Queue.put_nowait(item):相当于 put(item, False).
Queue.get(block=True, timeout=None):获取一个消息,其他同 put。
Queue.task_done():接收消息的线程通过调用这个函数来说明消息对应的任务已完成。
Queue.join():表示等待,等到队列为空,在执行别的操作。
Queue.terminate():表示强制关闭。
例子:
- #!/usr/bin/env python
- # -*- coding:utf-8 -*-
- from multiprocessing import Queue
- from threading import Thread
- import time
- """
- 写一个消费者和生产者,
- 用多线程方式实现,
- 通过类的重写的方法实现。
- """
- class Proceducer(Thread):
- def __init__(self, queue):
- super(Proceducer,self).__init__()
- self.queue = queue
- def run(self):
- try:
- for i in xrange(1, 10):
- print ("put data is {0} to queue".format(i))
- self.queue.put(i)
- except Exception as e:
- print ("put data error")
- raise e
- class Consumer_even(Thread):
- def __init__(self, queue):
- super(Consumer_even , self).__init__()
- self.queue = queue
- def run(self):
- try:
- while not self.queue.empty():
- number = self.queue.get(block=True, timeout=3)
- if number % 2 != 0:
- print("get {0} from queue EVEN, thread name is {1}".format(number, self.getName()))
- else:
- self.queue.put(number)
- time.sleep(1)
- except Exception as e:
- raise e
- class Consumer_odd(Thread):
- def __init__(self, queue):
- super(Consumer_odd , self).__init__()
- self.queue = queue
- def run(self):
- try:
- while not self.queue.empty():
- number = self.queue.get(block=True, timeout=3)
- if number % 2 == 0:
- print("get {0} from queue ODD".format(number))
- else:
- self.queue.put(number)
- time.sleep(1)
- except Exception as e:
- raise e
- def main():
- queue = Queue()
- p = Proceducer(queue=queue)
- p.start()
- p.join()
- time.sleep(1)
- c1 = Consumer_even(queue=queue)
- c2 = Consumer_odd(queue=queue)
- c1.start()
- c2.start()
- c1.join()
- c2.join()
- print ("All thread terminate!")
- if __name__ == '__main__':
- main()
结果:
- put data is 1 to queue
- put data is 2 to queue
- put data is 3 to queue
- put data is 4 to queue
- put data is 5 to queue
- put data is 6 to queue
- put data is 7 to queue
- put data is 8 to queue
- put data is 9 to queue
- get 1 from queue EVEN, thread name is Thread-2
- get 2 from queue ODD
- get 3 from queue EVEN, thread name is Thread-2
- get 4 from queue ODD
- get 5 from queue EVEN, thread name is Thread-2
- get 6 from queue ODD
- get 7 from queue EVEN, thread name is Thread-2
- get 8 from queue ODD
- get 9 from queue EVEN, thread name is Thread-2
- All thread terminate!
原文:http://blog.51cto.com/286577399/2051848
来源: http://www.bubuko.com/infodetail-2433720.html