只能保存为reponse.txt，不能保存为.xlsx格式，强行改完后无法打开

设置EXCEL文档的MIME类型

• application/vnd.ms-excel(正式)

• application/msexcel

• application/x-msexcel

• application/x-ms-excel

• application/x-excel

• application/x-dos_ms_excel

• application/xls

• application/x-xls

• application/vnd.openxmlformats-officedocument.spreadsheetml.sheet