java - FileUploadBase does not find any multipart parts when uploading small files -

i using spring's commonsmultipartresolver process file uploads in servlet 3 environment.

if uploaded file large, works fine.

if uploaded file smaller, resolver fails discover parts (with no exception thrown).

i have tracked down apache.commons.fileupload.fileitemiteratorimpl findnextitem() method returns false, despite there being multiple valid parts in post. results in no multipartfile object being available controller method.

when in debugger @ httpservletrequest see correct number of parts (getparts() returns correct number of parts).

i use httpservletrequest, except large files (>1mb), exception thrown maximum file size (which have configured commonsmultipartresolver evidently not cross on httpservletrequest).

i looked @ attempting configure servlet 3 maximum file size, don't want add several new classes application set size.

is there way upload smaller files using servlet 3 , commons-fileupload?

more

i have commons-fileupload configured maxuploadsizeperfile=100mb.

the following behavior results:

if uploaded file > 10mb, commons-fileupload processes , fine.

if uploaded file between ~3.8 mb , 10 mb, both input stream , underlying connection closed before commons-fileupload has chance parse request leading connection reset message in browser.

for uploaded files between 1 mb , ~3.8 mb, input stream closed, not underlying connection, allowing error page display error.

and finally, if uploaded file less 1 mb, underlying servlet 3 implementation handles parts before commons-fileupload gets invoked, leaving commons-fileupload believing there no parts in request.

this behavior results using spring boot (previously unbeknownst me) automatically configures multi-part servlet 3. causes underlying httpservletrequest process file upload before commons-fileupload has chance @ it.

the thing find curious @ point, why not fail if uploaded file large enough.