要求：获取下图指定网站的指定数据
空气质量状况报告-中国环境监测总站
输入：用户输入下载时间范围，格式为2022-10
输出：将更新时间在2022年10月1日到31日之间的文件下载到本地目录（可配置），并将下载的标题列表逐行打印在控制台console中
完成标准：
程序正常运行
import requests
from lxml import etree
from urllib.parse import urljoin
from datetime import datetimedef download_files(start_date,end_date):headers = {"User-Agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.0.0.0 Safari/537.36"}base_url = "http://www.cnemc.cn/jcbg/kqzlzkbg/index"page=0while True:if page==0:url=f"{base_url}.shtml"else:url=f"{base_url}_{page}.shtml"# url = "http://www.cnemc.cn/jcbg/kqzlzkbg/index.shtml"response = requests.get(url, headers=headers)if response.status_code!=200:breakresponse.encoding = response.apparent_encodingpage_text = response.texthtml = etree.HTML(page_text)divs = html.xpath('//*[@id="contentPageData"]/li')for i in divs:# 使用 XPath 定位到 <a> 标签并提取文本title = i.xpath('.//a/text()') # 获取第一个匹配元素的文本# 使用 XPath 定位到 <span class="txt_time"> 标签并提取文本date_str = i.xpath('.//span[@class="txt_time"]/text()')if title and date_str:title = title[0].strip()date = datetime.strptime(date_str[0].strip(),'%Y-%m-%d')if start_date <= date <= end_date:a_tag = i.find('.//a')link = a_tag.get('href') if a_tag is not None else Noneprint(f'下载标题：{title}')print(link)base_link='http://www.cnemc.cn/jcbg/kqzlzkbg/'full_link=urljoin(base_link,link)print(full_link)response_son = requests.get(full_link, headers=headers)response_son.encoding = response_son.apparent_encodingpage_text_son=response_son.text# print(page_text_son)html_son = etree.HTML(page_text_son)divs_son=html_son.xpath('/html/body/div[1]/div[5]/div/div[1]')[0]# print(divs_son) #/html/body/div[1]/div[5]/div/div[1]a_tag_son = divs_son.find('.//a')link_file = a_tag_son.get('href') if a_tag_son is not None else Noneprint(link_file)if "http://www.cnemc.cn/" not in link_file:link_file="http://www.cnemc.cn/jcbg/kqzlzkbg/"+str(start_date.year)+str(start_date.month)+'/'+link_file.lstrip('./')print(link_file)file_path=f"./downloads/{title}.pdf"response_file=requests.get(link_file)if response_file.status_code==200:with open(file_path,'wb') as f:f.write(response_file.content)print("文件下载成功，保存至:", file_path)else:print("下载失败，状态码:", response_file.status_code)page+=1
if __name__=="__main__":start_date=datetime(2016,4,1)end_date=datetime(2016,4,30)download_files(start_date,end_date)
