MultipartConfig annotation/servlet config

Question

If I use the annotation (@MultipartConfig(maxFileSize=XXX)) that works, but the web.xml variety (<max-file-size>XXX</max-file-size>) only seems to work when <file-size-threshold> is also present.

This seems wrong, am I right?

EDIT: When it does work (because I've added the file-size-threshold tag) and I upload a larger-than-the-limit file, I get a different exception than when I use the annotation. Definitely seems odd to me.

EDIT2: Just to add more detail, I get a SizeLimitExceededException when I set a max file size via the annotation, and get a FileSizeLimitExceededException when I set a max file size (with a 0 file size threshold to make it work at all). Both exceptions print the limit I set in the max file size in the exception message.

Answer 1

Actually the API Documentation for MultipartConfig specifies a default value of 0.

public abstract int fileSizeThreshold

The size threshold after which the file will be written to disk

Default:
0

Unfortunatelly the multipart-configType (in web-common_3_0.xsd) does not specify a default value:

<xsd:element name="file-size-threshold"
             type="xsd:integer"
             minOccurs="0"
             maxOccurs="1">
  <xsd:annotation>
    <xsd:documentation>

      The size threshold after which an uploaded file will be
      written to disk

    </xsd:documentation>
  </xsd:annotation>
</xsd:element>

I also couldn't find anything about it in JSR 315. While we could reason that minOccurs="0" implies that file-size-threshold is optional, there is nothing in the specs describing the intended behavior when this element is absent; so it is up to the vendor.

Hint: Try <file-size-threshold>0<file-size-threshold>

Hint 2: If it doesn't work open an issue for for the vendor (try the app Server issue tracker or the official issue tracker for whichever javax.servlet implementation you / they use). Do not use the word "wrong", instead go with terms such as "sensible defaults" and "metadata interoperability" (it will dramatically improve your chances):D.