要处理Google浏览器安装包下载异常和安全校验操作，可以使用Python的`requests`库来发送HTTP请求，并使用`hashlib`库进行SHA256哈希校验。以下是一个示例代码：
python
import os
import hashlib
import requests
def download_chrome_installer(url, save_path):
try:
response = requests.get(url, stream=True)
if response.status_code == 200:
with open(save_path, 'wb') as f:
for chunk in response.iter_content(chunk_size=1024):
if chunk:
f.write(chunk)
elif response.status_code == 404:
print("文件未找到")
else:
print("下载失败，状态码：", response.status_code)
except Exception as e:
print("下载过程中发生错误：", e)
def check_sha256(file_path):
sha256_hash = hashlib.sha256()
with open(file_path, 'rb') as f:
for byte_block in iter(lambda: f.read(4096), b""):
sha256_hash.update(byte_block)
return sha256_hash.hexdigest()
def main():
url = "https://dl.google.com/chrome/install/mac/latest/Installer.dmg"
save_path = "Downloads/Chrome.dmg"
download_chrome_installer(url, save_path)
file_path = os.path.join(os.getcwd(), save_path)
sha256_hash = check_sha256(file_path)
print("SHA256校验结果：", sha256_hash)
if __name__ == "__main__":
main()

这个代码首先定义了`download_chrome_installer`函数，用于下载Google浏览器的安装包。然后定义了`check_sha256`函数，用于计算文件的SHA256哈希值。最后，在`main`函数中调用这两个函数，完成下载和校验操作。