Queue對象實現一個fifo隊列（其他的還有lifo、priority隊列，這裏不再介紹）。

queue只有maxsize一個構造參數，用來指定隊列容量，指定為0的時候代表容量無限。

主要有以下成員函數：

Queue.qsize()：返回消息隊列的當前空間。返回的值不一定可靠。

Queue.empty()：判斷消息隊列是否為空，返回True或False。同樣不可靠。

Queue.not_empty()：判斷消息隊列是否為非空。同上不可靠。

Queue.full()：類似上邊，判斷消息隊列是否滿。

Queue.put(item, block=True, timeout=None)：往消息隊列中存放消息。block可以控制是否阻塞，timeout指定阻塞時候的等待時間。如果不阻塞或者超時，會引起一個full exception。

Queue.put_nowait(item)：相當於put(item, False).

Queue.get(block=True, timeout=None)：獲取一個消息，其他同put。

Queue.task_done()：接收消息的線程通過調用這個函數來說明消息對應的任務已完成。

Queue.join()：表示等待，等到隊列為空，在執行別的操作。

Queue.terminate()：表示強制關閉。

例子:

#!/usr/bin/env python
# -*- coding:utf-8 -*-

from multiprocessing import Queue
from threading import Thread
import time


"""
寫一個消費者和生產者，
用多線程方式實現，
通過類的重寫的方法實現。
"""

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()

結果：

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!

42. Python Queue 模塊