要将文件上传到SharePoint，可以使用以下解决方案，其中不使用SharePoint API：

1. 使用WebDAV协议：WebDAV是一种基于HTTP协议的文件管理协议，SharePoint支持WebDAV协议。您可以使用WebDAV客户端库将文件上传到SharePoint。

   示例代码：

   import requests
   
   def upload_file_to_sharepoint(file_path, sharepoint_url):
       with open(file_path, 'rb') as file:
           data = file.read()
       headers = {'Content-Type': 'application/octet-stream'}
       response = requests.put(sharepoint_url, headers=headers, data=data)
       if response.status_code == 200:
           print('File uploaded successfully.')
       else:
           print('File upload failed.')
   
   # 调用示例：
   file_path = 'path_to_file/file.txt'
   sharepoint_url = 'https://your_sharepoint_site.com/library/file.txt'
   upload_file_to_sharepoint(file_path, sharepoint_url)
   

   上述代码使用Python中的requests库将文件上传到SharePoint。您需要将file_path替换为要上传的文件路径，将sharepoint_url替换为SharePoint文档库中的目标文件URL。

2. 使用SharePoint前端页面：如果您可以手动上传文件到SharePoint网站的前端页面，那么您可以使用自动化工具（如Selenium）来模拟这个过程。

   示例代码：

   from selenium import webdriver
   
   def upload_file_to_sharepoint(file_path, sharepoint_url):
       driver = webdriver.Chrome()  # 使用Chrome浏览器
       driver.get(sharepoint_url)
       file_input = driver.find_element_by_css_selector('input[type="file"]')
       file_input.send_keys(file_path)
       upload_button = driver.find_element_by_id('upload-button')  # 替换为实际的上传按钮ID
       upload_button.click()
       driver.quit()
   
   # 调用示例：
   file_path = 'path_to_file/file.txt'
   sharepoint_url = 'https://your_sharepoint_site.com/library'
   upload_file_to_sharepoint(file_path, sharepoint_url)
   

   上述代码使用Python中的Selenium库来自动化上传文件操作。您需要将file_path替换为要上传的文件路径，将sharepoint_url替换为SharePoint文档库的URL。请注意，您需要根据实际的SharePoint页面结构和元素ID修改代码。

无论您选择使用WebDAV协议还是自动化工具，这些解决方案都可以在不使用SharePoint API的情况下将文件上传到SharePoint。