python 内置模块queue，队列

一、简介

多个线程之间的数据是共享的，多个线程进行数据交换的时候，不能够保证数据的安全性和一致性，所以当多个线程需要进行数据交换的时候，队列就出现了，队列可以完美解决线程间的数据交换，保证线程间数据的安全性和一致性。

二、队列类型

1. queue.Queue(maxsize=0) 先进先出

import randomqueue_data = [1,2,3,4,5,6]random.shuffle(queue_data)print('原数据：',queue_data)queue_test = queue.Queue()def queuePut(value): queue_test.put(value)for i in queue_data: queuePut(i)for i in range(len(queue_data)): print(queue_test.get())

2. queue.LifoQueue(maxsize=0) 先进后出

import queueimport randomqueue_data = [1,2,3,4,5,6]random.shuffle(queue_data)print('原数据：',queue_data)queue_test = queue.LifoQueue()def queuePut(value):    queue_test.put(value)for i in queue_data:    queuePut(i)for i in range(len(queue_data)):    print(queue_test.get())

3. queue.PriorityQueue(maxsize=0) 优先级队列级别越低越先出来

import queueimport randomqueue_data = [1,2,3,4,5,6]random.shuffle(queue_data)print('原数据：',queue_data)queue_test = queue.PriorityQueue()def queuePut(value): queue_test.put(value)for i in queue_data: queuePut(i)for i in range(len(queue_data)): print(queue_test.get())

4. queue.SimpleQueue(maxsize=0) 简化的队列，无跟踪任务的功能，只具有empty、get、put3个方法

三、队列方法

1. queue.qsize() 返回队列的大小
2. queue.empty() 如果队列为空，返回True,反之False
3. queue.full() 如果队列满了，返回True,反之False
4. queue.get(block,timeout) 获取队列，block：从队列里面取值，如果取不到值的话，程序不会结束， timeout：当block的值为真的时候，timeout是用来等待多少秒
5. queue.put(value,block,timeout) 写入队列，value：写入队列的值，,block：队列如果满了的话，再往队列里放值的话会等待， timeout：当block的值为真的时候，timeout是用来等待多少秒
6. queue.get_nowait() 相当于queue.get(False)
7. queue.put_nowait(value) 相当于queue.put(value, False)
8. queue.join() 阻塞调用线程，直到队列中的所有任务被处理掉, 实际上意味着等到队列为空，再执行别的操作
9. queue.task_done() 在完成一项工作之后，queue.task_done()函数向任务已经完成的队列发送一个信号
10. queue.full 与 maxsize 大小对应

四、队列+线程、队列+线程池

案例：简单的两人对话

1. 队列+线程，会导致线程频繁的创建，且主线程不关闭，其他线程就会一直开启

import queueimport threadingimport timeclass ChatSend(threading.Thread):    def __init__(self, name, message_queue):        super().__init__()        self.name = name        self.message_queue = message_queue    def run(self):        '''使用队列中的任务跟踪'''        message = input(f'{self.name}：')        self.message_queue.put({            'name': self.name,            'message': message,            'time': time.strftime('%Y-%m-%d %H:%M:%S',time.localtime())        })        self.message_queue.join()class ChatReceive(threading.Thread):    def __init__(self, name, message_queue):        super().__init__()        self.name = name        self.message_queue = message_queue    def run(self):        message_info = self.message_queue.get()        print(f'\n{message_info['time']}')        print(f'{self.name}接收到{message_info['name']}消息：{message_info['message']}\n')        self.message_queue.task_done()def chat(chat_person1, chat_person2):    message_queue = queue.Queue()    print(f'----------{chat_person1}和{chat_person2}正在对话----------')    while True:        send1 = ChatSend(chat_person1, message_queue)        receive1 = ChatReceive(chat_person2, message_queue)        send1.start()        receive1.start()        receive1.join()        send2 = ChatSend(chat_person2,message_queue)        receive2 = ChatReceive(chat_person1,message_queue)        send2.start()        receive2.start()        receive2.join()chat('张三', '李四')

2. 队列+线程+锁

import queueimport threadingimport timeclass ChatSend(threading.Thread): def __init__(self, name, message_queue, lock=None): super().__init__() self.name = name self.message_queue = message_queue self.lock = lock def run(self): self.lock.acquire() message = input(f'{self.name}：') self.message_queue.put({ 'name': self.name, 'message': message, 'time': time.strftime('%Y-%m-%d %H:%M:%S', time.localtime()) }) self.lock.notify() self.lock.release() class ChatReceive(threading.Thread): def __init__(self, name, message_queue, lock=None): super().__init__() self.name = name self.message_queue = message_queue self.lock = lock def run(self): self.lock.acquire() self.lock.wait() message_info = self.message_queue.get() print(f'\n{message_info['time']}') print(f'{self.name}接收到{message_info['name']}消息：{message_info['message']}\n') self.lock.release()def chat(chat_person1, chat_person2): message_queue = queue.Queue() lock = threading.Condition() print(f'----------{chat_person1}和{chat_person2}正在对话----------') while True: receive1 = ChatReceive(chat_person2, message_queue, lock) send1 = ChatSend(chat_person1, message_queue, lock) receive1.start() send1.start() receive1.join() receive2 = ChatReceive(chat_person1, message_queue, lock) send2 = ChatSend(chat_person2,message_queue, lock) receive2.start() send2.start() receive2.join()chat('张三', '李四')

3. 队列+池，不会频繁创建线程

import queueimport threadingimport timefrom concurrent.futures import ThreadPoolExecutor,waitlock = threading.Condition()class ChatSend:    def __init__(self, name, message_queue):        self.send_person = name        self.message_queue = message_queue    def run(self):        message = input(f'{self.send_person}：')        self.message_queue.put({            'name': self.send_person,            'message': message,            'time': time.strftime('%Y-%m-%d %H:%M:%S',time.localtime())        })        self.message_queue.join()class ChatReceive:    def __init__(self, name, message_queue):        self.receive_person = name        self.message_queue = message_queue    def run(self):        message_info = self.message_queue.get()        print(f'\n{message_info['time']}')        print(f'{message_info['name']}对{self.receive_person}说：{message_info['message']}\n')        self.message_queue.task_done()class Chat(ThreadPoolExecutor):    def __init__(self,person1, person2):        ThreadPoolExecutor.__init__(self,max_workers=2)        message_queue = queue.Queue()        print(f'----------{person1}和{person2}正在对话----------')        self.send1 = ChatSend(person1, message_queue)        self.receive1 = ChatReceive(person2, message_queue)        self.send2 = ChatSend(person2, message_queue)        self.receive2 = ChatReceive(person1, message_queue)    def start(self):        while True:            self.submit(self.send1.run)            self.submit(self.receive1.run)            self.submit(self.send2.run)            self.submit(self.receive2.run)chat = Chat('张三', '李四')chat.start()