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Date: Sat, 28 Feb 2004 15:08:16 -0800 (PST)
From: Martin Cooper <martinc@apache.org>
To: Jakarta Commons Users List <commons-user@jakarta.apache.org>
Subject: Re: Using FileUpload to send an e-mail with attachment with JavaMail
In-Reply-To: <403DC3DC.2040907@asiayeah.com>
Message-ID: <20040228142455.R13698@minotaur.apache.org>
References: <403DC3DC.2040907@asiayeah.com>
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On Thu, 26 Feb 2004, Tony Yat-Tung Cheung wrote:

> Hi,
>
> I am trying to make a servlet to receive a file with FileUpload, and
> then send out an e-mail with the received file as an attachment.
>
> The FileItem does not provide a way to get a DataSource out of it, which
> is required by the JavaMail's MimeBodyPart.
>
> Is there any way?
>
> The FileItem's API documentations seem to hint the solution, but I do
> not quite get the idea.
> "While this interface does not extend javax.activation.DataSource per se
> (to avoid a seldom used dependency), several of the defined methods are
> specifically defined with the same signatures as methods in that
> interface. This allows an implementation of this interface to also
> implement javax.activation.DataSource with minimal additional work."
>
> Do we have an easy solution here? I think it is one of the common
> applications of the commons-fileupload.

I disagree that it's common, especially given that you're the first to
ask, but it is simple to accomplish. ;-)

First, you'll want a class that implements DataSource. Just add it to
DefaultFileItem:

public class MyDefaultFileItem extends DefaultFileItem
                               implements DataSource {
    // Add any DataSource methods that DefaultFileItem doesn't
    // already implement
}

Now you need to get FileUpload to use this new class. That means you need
a factory:

public class MyDefaultFileItemFactory extends DefaultFileItemFactory {
    public FileItem createItem(...) {
        // Basically, just copy the one from the base class, but make
        // it instantiate your new class, above, instead of the default.
    }
}

You're almost done. Now all you need to do is construct your FileUpload
class and specify your own factory:

    DiskFileUpload upload = new DiskFileUpload(
            new MyDefaultFileItemFactory());

That's it. Now the file items you get back from FileUpload will be of your
own class, and so implement DataSource.

--
Martin Cooper


>
> Thank you very much.
>
> Best Regards,
> Tony Cheung
>
>
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