如何用Python发送HTTP请求？

import urllib.request
import urllib.parse

url = 'http://example.com'
params = {'key1': 'value1', 'key2': 'value2'}
data = urllib.parse.urlencode(params).encode('utf-8')

req = urllib.request.Request(url, data=data, method='POST')
with urllib.request.urlopen(req) as response:
    html = response.read()
    print(html.decode('utf-8'))

import requests

url = 'http://example.com'
params = {'key1': 'value1', 'key2': 'value2'}

response = requests.post(url, data=params)
print(response.text)

import requests

url = 'https://api.example.com/data'
payload = {'name': 'John', 'age': 30}

response = requests.post(url, json=payload)
if response.status_code == 200:
    data = response.json()
    print(data)
else:
    print(f"Request failed with status code: {response.status_code}")

response = requests.get(url, timeout=5)

try:
    response = requests.get(url)
    response.raise_for_status()
except requests.exceptions.RequestException as e:
    print(f"An error occurred: {e}")

with requests.Session() as session:
    session.get('http://example.com/login')
    response = session.get('http://example.com/protected')
    print(response.text)

import requests
from concurrent.futures import ThreadPoolExecutor

def fetch(url):
    return requests.get(url)

urls = ['http://example.com/page1', 'http://example.com/page2']
with ThreadPoolExecutor(max_workers=5) as executor:
    responses = list(executor.map(fetch, urls))
    for response in responses:
        print(response.text)

import requests
import requests_cache

requests_cache.install_cache('demo_cache', expire_after=300)

response = requests.get('http://example.com')
print(response.from_cache)  # 检查是否从缓存中获取