Why the fileName of MultipartFile which is uploaded is empty
<p>I want to import a file to server. But the fileName of MultipartFile which is uploaded is always empty. Following is my code.</p>

<p>XML</p>

<pre><code>&lt;bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"&gt;  
    &lt;property name="maxUploadSize" value="${web.maxUploadSize}" /&gt;  
&lt;/bean&gt;
</code></pre>

<p>JSP</p>

<pre><code>&lt;form id="importForm" action="${url}" method="post" enctype="multipart/form-data"
         style="padding-left:20px;text-align:center;" onsubmit="loading('Please wait...');"&gt;&lt;br/&gt;
        &lt;input id="uploadFile" name="file" type="file" style="width:330px"/&gt;
&lt;/form&gt;
</code></pre>

<p>JAVA</p>

<p><img src="https://i.stack.imgur.com/NxRTQ.png" alt="JAVA code and debug info"></p>

<p>What caused fileName empty? Any suggestion is welcome.</p>