Spring Boot File Upload Error: MissingServletRequestPartException: 'file' Not Found

This exception is thrown when the server expects a file to be uploaded as part of the request, but the file is not present in the request.

Possible causes for this exception are:

1. The client did not include the file in the request.

2. The file was included in the request, but with a different name than the one expected by the server.

3. The file was corrupted during transfer and was not properly received by the server.

To resolve this issue, make sure that the client is including the file in the request with the correct name and that the file is not corrupted during transfer.