Python 并发编程模式详解之多线程、多进程与异步IO

import threading
import time

# 模拟文件读取的函数
def read_file(file_name):
    time.sleep(2)  # 模拟IO操作耗时
    print(f"读取文件 {file_name} 完成")

# 创建线程列表
threads = []
files = ['file1.txt', 'file2.txt', 'file3.txt']

# 创建并启动线程
for file in files:
    thread = threading.Thread(target=read_file, args=(file,))
    threads.append(thread)
    thread.start()

# 等待所有线程完成
for thread in threads:
    thread.join()

print("所有文件读取完成")
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from multiprocessing import Process
import time

# 模拟CPU密集型任务的函数
def cpu_intensive_task(task_id):
    for _ in range(5):
        time.sleep(1)  # 模拟CPU计算耗时
    print(f"任务 {task_id} 完成")

# 创建进程列表
processes = []
tasks = [1, 2, 3]

# 创建并启动进程
for task in tasks:
    process = Process(target=cpu_intensive_task, args=(task,))
    processes.append(process)
    process.start()

# 等待所有进程完成
for process in processes:
    process.join()

print("所有任务完成")
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import asyncio
import aiohttp

async def fetch(session, url):
    async with session.get(url) as response:
        return await response.text()

async def main():
    urls = ['http://example.com', 'http://google.com', 'http://bing.com']
    tasks = []

    # 创建HTTP会话
    async with aiohttp.ClientSession() as session:
        for url in urls:
            task = asyncio.create_task(fetch(session, url))
            tasks.append(task)

        # 等待所有任务完成
        results = await asyncio.gather(*tasks)
        for i, result in enumerate(results):
            print(f"URL {urls[i]} 的内容是: {result[:100]}...")

# 运行异步主函数
asyncio.run(main())
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import threading
import asyncio
import aiohttp

# 异步下载文件的函数
async def download_file(session, url, file_name):
    async with session.get(url) as response:
        with open(file_name, 'wb') as f:
            f.write(await response.read())
    print(f"文件 {file_name} 下载完成")

# 多线程下载函数
def download_files_multithread(urls):
    loop = asyncio.new_event_loop()
    asyncio.set_event_loop(loop)
    tasks = []

    # 创建HTTP会话
    async with aiohttp.ClientSession() as session:
        for url in urls:
            file_name = url.split('/')[-1]
            task = loop.create_task(download_file(session, url, file_name))
            tasks.append(task)

        # 等待所有任务完成
        loop.run_until_complete(asyncio.gather(*tasks))

# 主函数
def main():
    urls = [
        'https://example.com/file1.zip',
        'https://example.com/file2.zip',
        'https://example.com/file3.zip'
    ]
    
    # 创建并启动线程
    threads = []
    for i in range(len(urls)):
        thread = threading.Thread(target=download_files_multithread, args=(urls[i:i+1],))
        threads.append(thread)
        thread.start()

    # 等待所有线程完成
    for thread in threads:
        thread.join()

    print("所有文件下载完成")

# 运行主函数
main()
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