Python爬虫基础编程

初学Python爬虫时都会从最简单的方法开始，以下为几种常见的基础做法。

"""
    简单的循环处理
"""
import requests


url_list = [
    "https://www.baidu.com",
"https://www.cnblogs.com/"
]

for url in url_list:
    result = requests.get(url)
    print(result.text)


"""
    线程池处理
"""
import requests
from concurrent.futures import ThreadPoolExecutor


def fetch_request(url):
    result = requests.get(url)
    print(result.text)


url_list = [
    "https://www.baidu.com/",
"https://www.cnblogs.com/"
]

pool = ThreadPoolExecutor(10)

for url in url_list:
    # 线程池中获取线程，执行fetch_request方法
pool.submit(fetch_request, url)

# 关闭线程池
pool.shutdown()

"""
    线程池+回调函数
"""
import requests
from concurrent.futures import ThreadPoolExecutor


def fetch_async(url):
    response = requests.get(url)
    return response


def callback(future):
    print(future.result().text)


url_list = [
    "https://www.baidu.com/",
"https://www.cnblogs.com/"
]

pool = ThreadPoolExecutor(10)

for url in url_list:
    v = pool.submit(fetch_async, url)
    # 调用回调函数
v.add_done_callback(callback)

pool.shutdown()

"""
    进程池处理
"""
import requests
from concurrent.futures import ProcessPoolExecutor


def fetch_requst(url):
    result = requests.get(url)
    print(result.text)


url_list = [
    "https://www.baidu.com/",
"https://www.cnblogs.com/"
]

if __name__ == '__main__':

    pool = ProcessPoolExecutor(max_workers=10)

    for url in url_list:
        pool.submit(fetch_requst, url)

    pool.shutdown()

"""
    进程池+回调函数
"""
import requests
from concurrent.futures import ProcessPoolExecutor


def fetch_async(url):
    response = requests.get(url)
    return response


def callback(future):
    print(future.result().text)


url_list = [
    "https://www.baidu.com/",
"https://www.cnblogs.com/"
]


if __name__ == '__main__':
    pool = ProcessPoolExecutor(10)

    for url in url_list:
        v = pool.submit(fetch_async, url)
        v.add_done_callback(callback)

    pool.shutdown()