Python 协程多进程并发访问URL：解决DeprecationWarning错误并优化代码

这个错误是因为在使用asyncio模块时没有创建事件循环（event loop）对象。可以通过在程序的开始处添加asyncio.get_event_loop()来解决这个问题。以下是一个实现从文本文件中读取URL并使用协程和多进程并发访问的示例代码：

import asyncio
import aiohttp
import concurrent.futures

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

async def process_batch(urls, max_processes):
    results = []
    with concurrent.futures.ProcessPoolExecutor(max_workers=max_processes) as executor:
        loop = asyncio.get_event_loop()
        tasks = [loop.run_in_executor(executor, fetch, url) for url in urls]
        for response in await asyncio.gather(*tasks):
            results.append(response)
    return results

async def main(filename, batch_size, max_processes):
    with open(filename, 'r') as file:
        urls = [line.strip() for line in file][:batch_size]
    return await process_batch(urls, max_processes)

if __name__ == '__main__':
    filename = 'urls.txt'
    batch_size = 10
    max_processes = 5

    loop = asyncio.get_event_loop()
    results = loop.run_until_complete(main(filename, batch_size, max_processes))
    loop.close()

    for result in results:
        print(result[:100])  # 打印每个URL的前100个字符

请确保在运行代码之前安装了aiohttp模块，可以通过运行pip install aiohttp来安装。另外，将filename变量设置为包含URL的文本文件的路径，batch_size变量设置为需要读取的URL行数，max_processes变量设置为每批最多的进程数。