以下是一个并行网络请求的示例代码，使用不同的方法进行比较：

1. 使用多线程：

import requests
import concurrent.futures

def fetch_url(url):
    response = requests.get(url)
    return response.text

urls = ['http://example.com', 'http://example.org', 'http://example.net']

with concurrent.futures.ThreadPoolExecutor() as executor:
    results = executor.map(fetch_url, urls)

for result in results:
    print(result)

2. 使用多进程：

import requests
import concurrent.futures

def fetch_url(url):
    response = requests.get(url)
    return response.text

urls = ['http://example.com', 'http://example.org', 'http://example.net']

with concurrent.futures.ProcessPoolExecutor() as executor:
    results = executor.map(fetch_url, urls)

for result in results:
    print(result)

3. 使用异步IO（协程）：

import asyncio
import aiohttp

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

urls = ['http://example.com', 'http://example.org', 'http://example.net']

async def main():
    tasks = [fetch_url(url) for url in urls]
    results = await asyncio.gather(*tasks)
    for result in results:
        print(result)

asyncio.run(main())

以上是三种常见的并行网络请求的方法，分别使用多线程、多进程和异步IO实现。具体使用哪种方法取决于你的需求和环境。