java - JSP: Get MIME Type on File Upload -

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i'm doing file upload, , want mime type uploaded file.

i trying use request.getcontenttype(), when call:

string contenttype = req.getcontenttype();

it return:

multipart/form-data; boundary=---------------------------310662768914663

how can correct value?

thanks in advance

it sounds if you're homegrowing multipart/form-data parser. wouldn't recommend that. rather use decent 1 apache commons fileupload. uploaded files, offers fileitem#getcontenttype() extract client-specified content type, if any.

string contenttype = item.getcontenttype();

if returns null (just because client didn't specify it), can take benefit of servletcontext#getmimetype() based on file name.

string filename = filenameutils.getname(item.getname()); string contenttype = getservletcontext().getmimetype(filename);

this resolved based on <mime-mapping> entries in servletcontainer's default web.xml (in case of example tomcat, it's present in /conf/web.xml) , on web.xml of webapp, if any, can expand/override servletcontainer's default mappings.

you need keep in mind value of multipart content type controlled client , client-provided file extension not need represent actual file content. instance, client edit file extension. careful when using information in business logic.

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