The request was rejected because no multipart boundary was found in springboot

The problem is that you are setting the Content-Type by yourself, let it be blank. Google Chrome will do it for you. The multipart Content-Type needs to know the file boundary, and when you remove the Content-Type, Postman will do it automagically for you.

Unchecked the content type in Postman and postman automatically detect the content type based on your input in the run time.

Sample

This worked for me: Uploading a file via Postman, to a SpringMVC backend webapp:

Backend: Endpoint controller definition

Postman: Headers setup POST Body setup

The "Postman - REST Client" is not suitable for doing post action with setting content-type.You can try to use "Advanced REST client" or others.

Additionally, headers was replace by consumes and produces since Spring 3.1 M2, see https://spring.io/blog/2011/06/13/spring-3-1-m2-spring-mvc-enhancements. And you can directly use produces = MediaType.MULTIPART_FORM_DATA_VALUE.

I was having the same problem while making a POST request from Postman and later I could solve the problem by setting a custom Content-Type with a boundary value set along with it like this.

I thought people can run into similar problem and hence, I'm sharing my solution.

postman

when I use postman to send a file which is 5.6M to external network , I met the same trouble. (The same action is succeeded on my own computer and local testing environment.) After check all the server configs and http headers, I found that the reason is Postman may have some trouble simulate request to external http request. Finally, I did the sendfile request on chrome html page successfully. Just as a reference :)

I met this problem because I use request.js which writen base on axios
And I already set a defaults.headers in request.js

import axios from 'axios'
const request = axios.create({
  baseURL: '', 
  timeout: 15000 
})
service.defaults.headers.post['Content-Type'] = 'application/x-www-form-urlencoded'

here is how I solve this
instead of

request.post('/manage/product/upload.do',
      param,config
    )

I use axios directly send request,and didn't add config

axios.post('/manage/product/upload.do',
      param
    )

hope this can solve your problem