Python多线程与异步IO的对比：何时选择哪种并发模型

import threading
import requests
def download_file(url, filename):
    response = requests.get(url)
    with open(filename, 'wb') as file:
        file.write(response.content)
    print(f'Downloaded {filename}')
urls = [
    'http://example.com/file1.txt',
    'http://example.com/file2.txt',
    # ... other URLs
]
threads = []
for i, url in enumerate(urls):
    filename = f'file{i + 1}.txt'
    thread = threading.Thread(target=download_file, args=(url, filename))
    thread.start()
    threads.append(thread)
# 等待所有线程完成
for thread in threads:
    thread.join()
print('All files downloaded.')

import aiohttp
import asyncio
async def download_file_async(session, url, filename):
    async with session.get(url) as response:
        data = await response.read()
        with open(filename, 'wb') as file:
            file.write(data)
        print(f'Downloaded {filename}')
async def main():
    urls = [
        'http://example.com/file1.txt',
        'http://example.com/file2.txt',
        # ... other URLs
    ]
    async with aiohttp.ClientSession() as session:
        downloads = [download_file_async(session, url, f'file{i + 1}.txt') for i, url in enumerate(urls)]
        await asyncio.gather(*downloads)
    print('All files downloaded.')
# 运行事件循环以执行异步操作
asyncio.run(main())