post请求参数类型：
content-type
1.Multipart/form-data
表单/文件上传(requests中files参数)->postman的binary
2.Application/x-www-form-urlencoded
纯表单(requests中data参数)->postman的form-data
3.Application/json
(requests中json参数)->postman的raw
4.Application/octet-stream
(requests中data参数)->postman的binary