用Python写一个爬虫：要求：1.网站地址：https://news.pdsu.edu.cn/xxyw.htm 2.获取底部分页页码 3.获取学校要闻中每页的所有新闻的标题、链接和发布日期 4.将标题、链接和发布日期存入excel

在Python中，我们可以使用`requests`, `BeautifulSoup`, 和 `pandas`库来完成这个任务。这里是一个基本的示例，首先需要安装缺失的库，如果尚未安装，可以使用pip：

pip install beautifulsoup4 requests pandas openpyxl

然后，我们可以按照以下步骤编写代码：

import requests
from bs4 import BeautifulSoup
import pandas as pd
from openpyxl import Workbook

def get_news_pages(url):
    response = requests.get(url)
    soup = BeautifulSoup(response.text, 'lxml')
    pagination = soup.find('div', class_='pagination')
    pages = [int(a.text) for a in pagination.find_all('a') if a.text.isdigit()]
    return pages

def parse_news_page(url, page_num):
    params = {'p': str(page_num)}
    response = requests.get(url, params=params)
    soup = BeautifulSoup(response.text, 'lxml')

    news_items = []
    for item in soup.find_all('div', class_='list-item'):
        title = item.h2.a.text
        link = item.h2.a['href']
        date = item.find('span', class_='time').text
        news_items.append({'title': title, 'link': link, 'date': date})

    return news_items

def save_to_excel(data, filename):
    df = pd.DataFrame(data)
    writer = pd.ExcelWriter(filename)
    df.to_excel(writer, sheet_name='News', index=False)
    writer.save()

url = 'https://news.pdsu.edu.cn/xxyw.htm'
pages = get_news_pages(url)

for page in pages:
    news_data = parse_news_page(url, page)
    save_to_excel(news_data, f'school_news_{page}.xlsx')