.dotx：application/vnd.openxmlformats-officedocument.wordprocessingml.template
.docx：application/vnd.openxmlformats-officedocument.wordprocessingml.document
.xlsx：application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
.pptx：application/vnd.openxmlformats-officedocument.presentationml.presentation
.doc：application/msword
.dot：application/msword
.xls：application/vnd.ms-excel
效果是这样的：