Python的多线程有效提高网络下载的并发能力和下载速度

import threading
import urllib.request

url = 'https://www.pidancode.com/bigfile.zip'  # 下载链接
num_threads = 4  # 线程数量

def download_part(start, end):
    headers = {'Range': f'bytes={start}-{end}'}
    req = urllib.request.Request(url, headers=headers)
    with urllib.request.urlopen(req) as f:
        data = f.read()
    return data

def main():
    with urllib.request.urlopen(url) as f:
        total_size = int(f.headers['Content-Length'])

    chunk_size = total_size // num_threads
    start = 0
    thread_pool = []

    # 启动多个线程同时下载
    for i in range(num_threads):
        end = start + chunk_size - 1 if i < num_threads - 1 else total_size - 1
        t = threading.Thread(target=download_part, args=(start, end))
        thread_pool.append(t)
        t.start()
        start = end + 1

    # 等待所有线程执行完毕
    for t in thread_pool:
        t.join()

    print('Download completed.')

if __name__ == '__main__':
    main()