python多线程-queue队列类型优先级队列，FIFO,LIFO

Queue在python3中重命名为queue，在python2到python3转换中可以自动转换

队列可应用在多个生产者多个消费者的模型中<<详情参考>>，并且在多线程中可用于线程之间数据信息的安全交换通信，防止冲突。

在队列中已经实现多线程的锁机制

队列Queue提供三种队列类型

主要区别是操作顺序的不同：

1.class Queue.Queue(maxsize=0)

FIFO队列，先进先出，maxsize定义队列长度，若maxsize等于0或者小于0，则该队列长度为无限，默认是无限

2.class Queue.LifoQueue(maxsize=0)

LIFO 后进先出，类似于堆栈，若maxsize等于0或者小于0，则该队列长度为无限，默认是无限

3.class Queue.PriorityQueue(maxsize=0)

优先级队列，值越低则优先级越高，若maxsize等于0或者小于0，则该队列长度为无限，默认是无限

异常：

1.exception Queue.Empty

当get()或get_nowait() 触发

2.exception Queue.Full

当put()或put_nowait()触发

三种队列均提供如下方法：

1.Queue.qsize() 队列长度，注：当qsize长度大于0时，get()并不一定成功，当长度小于maxsize时，put（）也不一定成功

2.Queue.empty() 是否队列为空，空True,反之False

3.Queue.full() 队列是否满，满True,反之False

4.Queue.get([block[, timeout]])

获取队列一个排队对象，timeout等待时间，如果get等待timeout时间，仍为空，则抛出异常。默认block为true timeout为null，一直等待有对象返回

5.Queue.get_nowait() 相当Queue.get(False)

6.Queue.put(item)

将一个对象写入队列，timeout等待时间，如果一个put等待了timeout时间，仍为满，则会抛出异常。默认block为true timeout为null，一直等待对象写入

7.Queue.put_nowait(item) 相当Queue.put(item, False)

8.Queue.task_done()

9.Queue.join() 相当与threading中将进程挂起，知道将子线程中的所有任务都处理完成后，才退出join，进行后面的步骤

例如模型：

def worker():

while True:

item = q.get()

do_work(item)

q.task_done()

q = Queue()

for i in range(num_worker_threads):

t = Thread(target=worker)

t.daemon = True

t.start()

for item in source():

q.put(item)

q.join()

1.FIFO队列先进先出：

#coding=utf8
import Queue

queuelist = Queue.Queue()

for i in range():
    if not queuelist.full():
       queuelist.put(i)
       print "put list : %s ,now queue size is %s "%(i,queuelist.qsize())

while not queuelist.empty():
    print "get list : %s , now queue size is %s"%(queuelist.get(),queuelist.qsize())
           

输出：

put list :  ,now queue size is  
put list :  ,now queue size is  
put list :  ,now queue size is  
put list :  ,now queue size is  
put list :  ,now queue size is  
get list :  , now queue size is 
get list :  , now queue size is 
get list :  , now queue size is 
get list :  , now queue size is 
get list :  , now queue size is 
           

2.LIFO队列先进后出：

#coding=utf8
import Queue

queuelist = Queue.LifoQueue()

for i in range():
    if not queuelist.full():
       queuelist.put(i)
       print "put list : %s ,now queue size is %s "%(i,queuelist.qsize())

while not queuelist.empty():
    print "get list : %s , now queue size is %s"%(queuelist.get(),queuelist.qsize())
           

输出：

put list :  ,now queue size is  
put list :  ,now queue size is  
put list :  ,now queue size is  
put list :  ,now queue size is  
put list :  ,now queue size is  
get list :  , now queue size is 
get list :  , now queue size is 
get list :  , now queue size is 
get list :  , now queue size is 
get list :  , now queue size is 
           

3.优先队列PriorityQueue

ps:这个优先队列有些垃圾，没有直接传入优先级的参数

示例：

#coding=utf8
import Queue
import random

queuelist = Queue.PriorityQueue()

for i in range():
    if not queuelist.full():
        x=random.randint(,)
        y=random.randint(,)
        print y,x
        queuelist.put({y:"th-%d"%x})

while not queuelist.empty():
    print "get list : %s , now queue size is %s"%(queuelist.get(),queuelist.qsize())
           

输出：

get list : {: 'th-19'} , now queue size is 
get list : {: 'th-13'} , now queue size is 
get list : {: 'th-5'} , now queue size is 
get list : {: 'th-20'} , now queue size is 
get list : {: 'th-16'} , now queue size is 
           

优先级优先值传入的几种传入方法：

将queuelist.put({y:”th-%d”%x})可替换为如下：

1.queuelist.put((y,”th-%d”%x))

2.queuelist.put([y,”th-%d”%x])

若不可替换queuelist.put({y:”th-%d”%x})修改为如下put，没有想要的优先队列效果：

1.queuelist.put(y,”th-%d”%x)

2.queuelist.put({y,”th-%d”%x})

检票综合示例：

模拟检票过程

排3队进行检票，一个队列一个线程

票有编号

检票时间有固定窗口，若时间到了通知队列关闭

#coding=utf8

import Queue
import threading
import time

exitsingle = 

class myThread(threading.Thread):
    def __init__(self, threadname, queuelist):
        threading.Thread.__init__(self)
        self.threadname = threadname
        self.queuelist = queuelist

    def run(self):
        print "Starting queue %s"%self.threadname
        queue_enter(self.threadname, self.queuelist)
        time.sleep()
        print "close  " + self.threadname

def queue_enter(threadname, queuelist):
    while not exitsingle:
        queueLock.acquire()
        if not workQueue.empty():
            data = queuelist.get()
            queueLock.release()
            print "%s check ticket %s" % (threadname, data)
        else:
            queueLock.release()
        time.sleep()


threadList = ["list-1", "list-2", "list-3"]
queueLock = threading.Lock()
workQueue = Queue.Queue()
threads = []

queueLock.acquire()
for num in range(,):
    workQueue.put(num)

queueLock.release()

print "start .."

for name in threadList:
    thread = myThread( name, workQueue)
    thread.start()
    threads.append(thread)

while not workQueue.empty():
     pass

exitsingle = 

for t in threads:
    t.join()
print "stop enter.."
           

输出：

start ..
Starting queue list-
list- check ticket 
Starting queue list-
list- check ticket 
Starting queue list-
list- check ticket 
list- check ticket 
list- check ticket 
list- check ticket 
list- check ticket 
list- check ticket 
list- check ticket 
list- check ticket 
list- check ticket 
list- check ticket 
list- check ticket 
list- check ticket 
list- check ticket 
list- check ticket 
list- check ticket 
list- check ticket 
list- check ticket 
close  list-
close  list-
close  list-
stop enter..