Commons FileUpload example source code file (faq.fml)

This example Commons FileUpload source code file (faq.fml) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Commons FileUpload tags/keywords

commons, fileupload, fileupload, i, io, license, license, see, struts, struts, the, the, why, you

The Commons FileUpload faq.fml source code

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<faqs title="FileUpload FAQ">

  <part id="general">
    <title>General

    <faq id="empty-parse">
      <question>
        Why is parseRequest() returning no items?
      </question>
      <answer>
        This most commonly happens when the request has already been parsed, or
        processed in some other way. Since the input stream has aleady been
        consumed by that earlier process, it is no longer available for parsing
        by Commons FileUpload.
      </answer>
    </faq>

    <faq id="read-timeout">
      <question>
        Why am I getting "Read timed out" exceptions while parsing?
      </question>
      <answer>
        The most common cause of these exceptions is when FileUpload is being
        used on a site that is using the Tomcat ISAPI redirector. There was a
        bug in earlier versions of that component that caused problems with
        multipart requests. The bug was fixed some time ago, so you probably
        just need to pick up a newer version. See the
        <a href="http://issues.apache.org/bugzilla/show_bug.cgi?id=15278">Tomcat bug report
        for full details.
      </answer>
    </faq>

    <faq id="class-not-found">
      <question>
        Why is NoClassDefFoundError being thrown?
      </question>
      <answer>
        <p>There are two common causes for this error. 

        
        <p>Firstly, it might simply mean that you do not have the Commons IO 
        jar in your classpath. FileUpload depends on IO (see 
        <a href="dependencies.html">dependencies) - you can tell if 
        this is the case if the missing class is within the 
        <code>org.apache.commons.io package. 


        <p>Secondly this happens when attempting to rely on a shared copy of
        the Commons FileUpload jar file provided by your web container. The
        solution is to include the FileUpload jar file as part of your own
        web application, instead of relying on the container. The same may 
        hold for FileUpload's IO dependency. </p>
      </answer>
    </faq>

    <faq id="whole-path-from-IE">
      <question>
        Why does FileItem.getName() return the whole path, and not just the file name?
      </question>
      <answer>
        Internet Explorer provides the entire path to the uploaded file and not
        just the base file name. Since FileUpload provides exactly what was
        supplied by the client (browser), you may want to remove this path
        information in your application. You can do that using the following
        method from Commons IO (which you already have, since it is used by
        FileUpload).
        <pre>
    String fileName = item.getName();
    if (fileName != null) {
        filename = FilenameUtils.getName(filename);
    }
        </pre>
      </answer>
    </faq>
  </part>

  <part id="struts">
    <title>FileUpload and Struts

    <faq id="parse-in-action-fails">
      <question>
        I'm using FileUpload in an Action, but it's not working. Why?
      </question>
      <answer>
        Struts recognises multipart requests, and parses them automatically,
        presenting the request parameters to your code in the same manner as
        if they were regular request parameters. Since Struts has already
        processed the request, and made it available in your form bean, the
        input stream is no longer available for parsing, so attempting to do
        so with FileUpload will fail.
      </answer>
    </faq>

    <faq id="howto-parse-in-action">
      <question>
        But I need to parse the request myself. How can I do that?
      </question>
      <answer>
        Struts parses multipart a request as a part of the process of populating
        your form bean from that request. If, for some reason, you need to have
        full control over the multipart parsing, you can do so by configuring
        your action mapping without an associated form bean. (A better way of
        doing this, however, is to replace the default multipart handler with
        your own. See the Struts documentation for details.)
      </answer>
    </faq>
  </part>

</faqs>