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<h1 class="no_toc" id="file-upload">File Upload</h1>
<ul id="markdown-toc">
<li><a href="#dependencies" id="markdown-toc-dependencies">Dependencies</a> <ul>
<li><a href="#struts-20x-file-upload-dependencies" id="markdown-toc-struts-20x-file-upload-dependencies">Struts 2.0.x File Upload Dependencies</a></li>
<li><a href="#struts-21x-file-upload-dependencies" id="markdown-toc-struts-21x-file-upload-dependencies">Struts 2.1.x File Upload Dependencies</a></li>
</ul>
</li>
<li><a href="#basic-usage" id="markdown-toc-basic-usage">Basic Usage</a> <ul>
<li><a href="#example-action-mapping" id="markdown-toc-example-action-mapping">Example action mapping:</a></li>
<li><a href="#example-jsp-form-tags" id="markdown-toc-example-jsp-form-tags">Example JSP form tags:</a></li>
<li><a href="#example-action-class" id="markdown-toc-example-action-class">Example Action class:</a></li>
</ul>
</li>
<li><a href="#uploading-multiple-files" id="markdown-toc-uploading-multiple-files">Uploading Multiple Files</a> <ul>
<li><a href="#uploading-multiple-files-using-arrays" id="markdown-toc-uploading-multiple-files-using-arrays">Uploading Multiple Files using Arrays</a></li>
<li><a href="#uploading-multiple-files-using-lists" id="markdown-toc-uploading-multiple-files-using-lists">Uploading Multiple Files using Lists</a></li>
</ul>
</li>
<li><a href="#advanced-configuration" id="markdown-toc-advanced-configuration">Advanced Configuration</a> <ul>
<li><a href="#file-size-limits" id="markdown-toc-file-size-limits">File Size Limits</a></li>
<li><a href="#file-types" id="markdown-toc-file-types">File Types</a></li>
<li><a href="#error-messages" id="markdown-toc-error-messages">Error Messages</a></li>
<li><a href="#temporary-directories" id="markdown-toc-temporary-directories">Temporary Directories</a></li>
<li><a href="#alternate-libraries" id="markdown-toc-alternate-libraries">Alternate Libraries</a></li>
<li><a href="#request-validation" id="markdown-toc-request-validation">Request validation</a></li>
<li><a href="#disabling-file-upload-support" id="markdown-toc-disabling-file-upload-support">Disabling file upload support</a></li>
</ul>
</li>
</ul>
<p>The Struts 2 framework provides built-in support for processing file uploads that conform to <a href="http://www.ietf.org/rfc/rfc1867.txt">RFC 1867</a>,
“Form-based File Upload in HTML”. When correctly configured the framework will pass uploaded file(s) into your Action class.
Support for individual and multiple file uploads are provided. When a file is uploaded it will typically be stored in a temporary directory.
Uploaded files should be processed or moved by your Action class to ensure the data is not lost. Be aware that servers may have a security
policy in place that prohibits you from writing to directories other than the temporary directory and the directories that belong to your
web application.</p>
<h2 id="dependencies">Dependencies</h2>
<p>The Struts 2 framework leverages add-on libraries to handle the parsing of uploaded files. These libraries are not included in the Struts
distribution, you must add them into your project. The libraries needed are:</p>
<table>
<thead>
<tr>
<th>Library</th>
<th>URL</th>
<th>Struts 2.0.x</th>
<th>Struts 2.1.x</th>
<th>Struts 2.5.x</th>
</tr>
</thead>
<tbody>
<tr>
<td>Commons-FileUpload</td>
<td><a href="http://commons.apache.org/fileupload/">http://commons.apache.org/fileupload/</a></td>
<td>1.1.1</td>
<td>1.2.1</td>
<td>1.3.2</td>
</tr>
<tr>
<td>Commons-IO</td>
<td><a href="http://commons.apache.org/io/">http://commons.apache.org/io/</a></td>
<td>1.0</td>
<td>1.3.2</td>
<td>2.4</td>
</tr>
</tbody>
</table>
<p>If you are using Maven then you can add these libraries as dependencies in your project’s pom.xml.</p>
<h3 id="struts-20x-file-upload-dependencies">Struts 2.0.x File Upload Dependencies</h3>
<div class="language-xml highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;dependency&gt;</span>
<span class="nt">&lt;groupId&gt;</span>commons-fileupload<span class="nt">&lt;/groupId&gt;</span>
<span class="nt">&lt;artifactId&gt;</span>commons-fileupload<span class="nt">&lt;/artifactId&gt;</span>
<span class="nt">&lt;version&gt;</span>1.1.1<span class="nt">&lt;/version&gt;</span>
<span class="nt">&lt;/dependency&gt;</span>
<span class="nt">&lt;dependency&gt;</span>
<span class="nt">&lt;groupId&gt;</span>commons-io<span class="nt">&lt;/groupId&gt;</span>
<span class="nt">&lt;artifactId&gt;</span>commons-io<span class="nt">&lt;/artifactId&gt;</span>
<span class="nt">&lt;version&gt;</span>1.0<span class="nt">&lt;/version&gt;</span>
<span class="nt">&lt;/dependency&gt;</span>
</code></pre></div></div>
<h3 id="struts-21x-file-upload-dependencies">Struts 2.1.x File Upload Dependencies</h3>
<div class="language-xml highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;dependency&gt;</span>
<span class="nt">&lt;groupId&gt;</span>commons-fileupload<span class="nt">&lt;/groupId&gt;</span>
<span class="nt">&lt;artifactId&gt;</span>commons-fileupload<span class="nt">&lt;/artifactId&gt;</span>
<span class="nt">&lt;version&gt;</span>1.2.1<span class="nt">&lt;/version&gt;</span>
<span class="nt">&lt;/dependency&gt;</span>
<span class="nt">&lt;dependency&gt;</span>
<span class="nt">&lt;groupId&gt;</span>commons-io<span class="nt">&lt;/groupId&gt;</span>
<span class="nt">&lt;artifactId&gt;</span>commons-io<span class="nt">&lt;/artifactId&gt;</span>
<span class="nt">&lt;version&gt;</span>1.3.2<span class="nt">&lt;/version&gt;</span>
<span class="nt">&lt;/dependency&gt;</span>
</code></pre></div></div>
<h2 id="basic-usage">Basic Usage</h2>
<p>The <code class="highlighter-rouge">org.apache.struts2.interceptor.FileUploadInterceptor</code> class is included as part of the <code class="highlighter-rouge">defaultStack</code>. As long as the required libraries
are added to your project you will be able to take advantage of of the Struts 2 fileUpload capability. Configure an Action mapping for your
Action class as you typically would.</p>
<h3 id="example-action-mapping">Example action mapping:</h3>
<div class="language-xml highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;action</span> <span class="na">name=</span><span class="s">"doUpload"</span> <span class="na">class=</span><span class="s">"com.example.UploadAction"</span><span class="nt">&gt;</span>
<span class="nt">&lt;result</span> <span class="na">name=</span><span class="s">"success"</span><span class="nt">&gt;</span>good_result.jsp<span class="nt">&lt;/result&gt;</span>
<span class="nt">&lt;/action&gt;</span>
</code></pre></div></div>
<p>A form must be create with a form field of type file, <code class="highlighter-rouge">&lt;INPUT type="file" name="upload"&gt;</code>. The form used to upload the file must have its
encoding type set to <code class="highlighter-rouge">multipart/form-data</code>, <code class="highlighter-rouge">&lt;form action="doUpload" enctype="multipart/form-data" method="post"&gt;</code>. The standard procedure
for adding these elements is by using the Struts 2 tag libraries as shown in the following example:</p>
<h3 id="example-jsp-form-tags">Example JSP form tags:</h3>
<div class="language-xml highlighter-rouge"><div class="highlight"><pre class="highlight"><code> <span class="nt">&lt;s:form</span> <span class="na">action=</span><span class="s">"doUpload"</span> <span class="na">method=</span><span class="s">"post"</span> <span class="na">enctype=</span><span class="s">"multipart/form-data"</span><span class="nt">&gt;</span>
<span class="nt">&lt;s:file</span> <span class="na">name=</span><span class="s">"upload"</span> <span class="na">label=</span><span class="s">"File"</span><span class="nt">/&gt;</span>
<span class="nt">&lt;s:submit/&gt;</span>
<span class="nt">&lt;/s:form&gt;</span>
</code></pre></div></div>
<p>The fileUpload interceptor will use setter injection to insert the uploaded file and related data into your Action class. For a form field
named <code class="highlighter-rouge">upload</code> you would provide the three setter methods shown in the following example:</p>
<h3 id="example-action-class">Example Action class:</h3>
<div class="language-java highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="kn">package</span> <span class="n">com</span><span class="o">.</span><span class="na">example</span><span class="o">;</span>
<span class="kn">import</span> <span class="nn">java.io.File</span><span class="o">;</span>
<span class="kn">import</span> <span class="nn">com.opensymphony.xwork2.ActionSupport</span><span class="o">;</span>
<span class="kd">public</span> <span class="kd">class</span> <span class="nc">UploadAction</span> <span class="kd">extends</span> <span class="n">ActionSupport</span> <span class="o">{</span>
<span class="kd">private</span> <span class="n">File</span> <span class="n">file</span><span class="o">;</span>
<span class="kd">private</span> <span class="n">String</span> <span class="n">contentType</span><span class="o">;</span>
<span class="kd">private</span> <span class="n">String</span> <span class="n">filename</span><span class="o">;</span>
<span class="kd">public</span> <span class="kt">void</span> <span class="nf">setUpload</span><span class="o">(</span><span class="n">File</span> <span class="n">file</span><span class="o">)</span> <span class="o">{</span>
<span class="k">this</span><span class="o">.</span><span class="na">file</span> <span class="o">=</span> <span class="n">file</span><span class="o">;</span>
<span class="o">}</span>
<span class="kd">public</span> <span class="kt">void</span> <span class="nf">setUploadContentType</span><span class="o">(</span><span class="n">String</span> <span class="n">contentType</span><span class="o">)</span> <span class="o">{</span>
<span class="k">this</span><span class="o">.</span><span class="na">contentType</span> <span class="o">=</span> <span class="n">contentType</span><span class="o">;</span>
<span class="o">}</span>
<span class="kd">public</span> <span class="kt">void</span> <span class="nf">setUploadFileName</span><span class="o">(</span><span class="n">String</span> <span class="n">filename</span><span class="o">)</span> <span class="o">{</span>
<span class="k">this</span><span class="o">.</span><span class="na">filename</span> <span class="o">=</span> <span class="n">filename</span><span class="o">;</span>
<span class="o">}</span>
<span class="kd">public</span> <span class="n">String</span> <span class="nf">execute</span><span class="o">()</span> <span class="o">{</span>
<span class="c1">//...</span>
<span class="k">return</span> <span class="n">SUCCESS</span><span class="o">;</span>
<span class="o">}</span>
<span class="o">}</span>
</code></pre></div></div>
<p>The purpose of each one of these methods is described in the table below. Notice that if you have multiple file form elements with different
names you would be required to have another corresponding set of these methods for each file uploaded.</p>
<table>
<thead>
<tr>
<th>Method Signature</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr>
<td><code class="highlighter-rouge">setX(File file)</code></td>
<td>The file that contains the content of the uploaded file. This is a temporary file and file.getName() will not return the original name of the file</td>
</tr>
<tr>
<td><code class="highlighter-rouge">setXContentType(String contentType)</code></td>
<td>The mime type of the uploaded file</td>
</tr>
<tr>
<td><code class="highlighter-rouge">setXFileName(String fileName)</code></td>
<td>The actual file name of the uploaded file (not the HTML name)</td>
</tr>
</tbody>
</table>
<h2 id="uploading-multiple-files">Uploading Multiple Files</h2>
<p>As mentioned in the previous section one technique for uploading multiple files would be to simply have multiple form input elements of type
file all with different names. This would require a number of setter methods that was equal to 3 times the number of files being uploaded.
Another option is to use Arrays or java.util.Lists. The following examples are taken from the Showcase example application that is part
sample applications you can download at <a href="http://struts.apache.org/download.cgi">http://struts.apache.org/download.cgi</a>. For the Action mapping
details see <code class="highlighter-rouge">struts-fileupload.xml</code> in the sample application download.</p>
<h3 id="uploading-multiple-files-using-arrays">Uploading Multiple Files using Arrays</h3>
<p><code class="highlighter-rouge">multipleUploadUsingArray.jsp</code> Notice all file input types have the same name.</p>
<pre><code class="language-jsp">&lt;s:form action="doMultipleUploadUsingArray" method="POST" enctype="multipart/form-data"&gt;
&lt;s:file label="File (1)" name="upload" /&gt;
&lt;s:file label="File (2)" name="upload" /&gt;
&lt;s:file label="FIle (3)" name="upload" /&gt;
&lt;s:submit cssClass="btn btn-primary"/&gt;
&lt;/s:form&gt;
</code></pre>
<p><code class="highlighter-rouge">MultipleFileUploadUsingArrayAction.java</code></p>
<div class="language-java highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="kd">public</span> <span class="kd">class</span> <span class="nc">MultipleFileUploadUsingArrayAction</span> <span class="kd">extends</span> <span class="n">ActionSupport</span> <span class="o">{</span>
<span class="kd">private</span> <span class="n">File</span><span class="o">[]</span> <span class="n">uploads</span><span class="o">;</span>
<span class="kd">private</span> <span class="n">String</span><span class="o">[]</span> <span class="n">uploadFileNames</span><span class="o">;</span>
<span class="kd">private</span> <span class="n">String</span><span class="o">[]</span> <span class="n">uploadContentTypes</span><span class="o">;</span>
<span class="kd">public</span> <span class="n">String</span> <span class="nf">upload</span><span class="o">()</span> <span class="kd">throws</span> <span class="n">Exception</span> <span class="o">{</span>
<span class="n">System</span><span class="o">.</span><span class="na">out</span><span class="o">.</span><span class="na">println</span><span class="o">(</span><span class="s">"\n\n upload2"</span><span class="o">);</span>
<span class="n">System</span><span class="o">.</span><span class="na">out</span><span class="o">.</span><span class="na">println</span><span class="o">(</span><span class="s">"files:"</span><span class="o">);</span>
<span class="k">for</span> <span class="o">(</span><span class="n">File</span> <span class="n">u</span> <span class="o">:</span> <span class="n">uploads</span><span class="o">)</span> <span class="o">{</span>
<span class="n">System</span><span class="o">.</span><span class="na">out</span><span class="o">.</span><span class="na">println</span><span class="o">(</span><span class="s">"*** "</span> <span class="o">+</span> <span class="n">u</span> <span class="o">+</span> <span class="s">"\t"</span> <span class="o">+</span> <span class="n">u</span><span class="o">.</span><span class="na">length</span><span class="o">());</span>
<span class="o">}</span>
<span class="n">System</span><span class="o">.</span><span class="na">out</span><span class="o">.</span><span class="na">println</span><span class="o">(</span><span class="s">"filenames:"</span><span class="o">);</span>
<span class="k">for</span> <span class="o">(</span><span class="n">String</span> <span class="n">n</span> <span class="o">:</span> <span class="n">uploadFileNames</span><span class="o">)</span> <span class="o">{</span>
<span class="n">System</span><span class="o">.</span><span class="na">out</span><span class="o">.</span><span class="na">println</span><span class="o">(</span><span class="s">"*** "</span> <span class="o">+</span> <span class="n">n</span><span class="o">);</span>
<span class="o">}</span>
<span class="n">System</span><span class="o">.</span><span class="na">out</span><span class="o">.</span><span class="na">println</span><span class="o">(</span><span class="s">"content types:"</span><span class="o">);</span>
<span class="k">for</span> <span class="o">(</span><span class="n">String</span> <span class="n">c</span> <span class="o">:</span> <span class="n">uploadContentTypes</span><span class="o">)</span> <span class="o">{</span>
<span class="n">System</span><span class="o">.</span><span class="na">out</span><span class="o">.</span><span class="na">println</span><span class="o">(</span><span class="s">"*** "</span> <span class="o">+</span> <span class="n">c</span><span class="o">);</span>
<span class="o">}</span>
<span class="n">System</span><span class="o">.</span><span class="na">out</span><span class="o">.</span><span class="na">println</span><span class="o">(</span><span class="s">"\n\n"</span><span class="o">);</span>
<span class="k">return</span> <span class="n">SUCCESS</span><span class="o">;</span>
<span class="o">}</span>
<span class="kd">public</span> <span class="n">File</span><span class="o">[]</span> <span class="nf">getUpload</span><span class="o">()</span> <span class="o">{</span>
<span class="k">return</span> <span class="k">this</span><span class="o">.</span><span class="na">uploads</span><span class="o">;</span>
<span class="o">}</span>
<span class="kd">public</span> <span class="kt">void</span> <span class="nf">setUpload</span><span class="o">(</span><span class="n">File</span><span class="o">[]</span> <span class="n">upload</span><span class="o">)</span> <span class="o">{</span>
<span class="k">this</span><span class="o">.</span><span class="na">uploads</span> <span class="o">=</span> <span class="n">upload</span><span class="o">;</span>
<span class="o">}</span>
<span class="kd">public</span> <span class="n">String</span><span class="o">[]</span> <span class="nf">getUploadFileName</span><span class="o">()</span> <span class="o">{</span>
<span class="k">return</span> <span class="k">this</span><span class="o">.</span><span class="na">uploadFileNames</span><span class="o">;</span>
<span class="o">}</span>
<span class="kd">public</span> <span class="kt">void</span> <span class="nf">setUploadFileName</span><span class="o">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">uploadFileName</span><span class="o">)</span> <span class="o">{</span>
<span class="k">this</span><span class="o">.</span><span class="na">uploadFileNames</span> <span class="o">=</span> <span class="n">uploadFileName</span><span class="o">;</span>
<span class="o">}</span>
<span class="kd">public</span> <span class="n">String</span><span class="o">[]</span> <span class="nf">getUploadContentType</span><span class="o">()</span> <span class="o">{</span>
<span class="k">return</span> <span class="k">this</span><span class="o">.</span><span class="na">uploadContentTypes</span><span class="o">;</span>
<span class="o">}</span>
<span class="kd">public</span> <span class="kt">void</span> <span class="nf">setUploadContentType</span><span class="o">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">uploadContentType</span><span class="o">)</span> <span class="o">{</span>
<span class="k">this</span><span class="o">.</span><span class="na">uploadContentTypes</span> <span class="o">=</span> <span class="n">uploadContentType</span><span class="o">;</span>
<span class="o">}</span>
<span class="o">}</span>
</code></pre></div></div>
<h3 id="uploading-multiple-files-using-lists">Uploading Multiple Files using Lists</h3>
<p><code class="highlighter-rouge">multipleUploadUsingList.jsp</code> Notice all file input types have the same name.</p>
<pre><code class="language-jsp">&lt;s:form action="doMultipleUploadUsingList" method="POST" enctype="multipart/form-data"&gt;
&lt;s:file label="File (1)" name="upload" /&gt;
&lt;s:file label="File (2)" name="upload" /&gt;
&lt;s:file label="FIle (3)" name="upload" /&gt;
&lt;s:submit cssClass="btn btn-primary"/&gt;
&lt;/s:form&gt;
</code></pre>
<p><code class="highlighter-rouge">MultipleFileUploadUsingListAction.java</code></p>
<div class="language-java highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="kd">public</span> <span class="kd">class</span> <span class="nc">MultipleFileUploadUsingListAction</span> <span class="kd">extends</span> <span class="n">ActionSupport</span> <span class="o">{</span>
<span class="kd">private</span> <span class="n">List</span><span class="o">&lt;</span><span class="n">File</span><span class="o">&gt;</span> <span class="n">uploads</span> <span class="o">=</span> <span class="k">new</span> <span class="n">ArrayList</span><span class="o">&lt;</span><span class="n">File</span><span class="o">&gt;();</span>
<span class="kd">private</span> <span class="n">List</span><span class="o">&lt;</span><span class="n">String</span><span class="o">&gt;</span> <span class="n">uploadFileNames</span> <span class="o">=</span> <span class="k">new</span> <span class="n">ArrayList</span><span class="o">&lt;</span><span class="n">String</span><span class="o">&gt;();</span>
<span class="kd">private</span> <span class="n">List</span><span class="o">&lt;</span><span class="n">String</span><span class="o">&gt;</span> <span class="n">uploadContentTypes</span> <span class="o">=</span> <span class="k">new</span> <span class="n">ArrayList</span><span class="o">&lt;</span><span class="n">String</span><span class="o">&gt;();</span>
<span class="kd">public</span> <span class="n">List</span><span class="o">&lt;</span><span class="n">File</span><span class="o">&gt;</span> <span class="nf">getUpload</span><span class="o">()</span> <span class="o">{</span>
<span class="k">return</span> <span class="k">this</span><span class="o">.</span><span class="na">uploads</span><span class="o">;</span>
<span class="o">}</span>
<span class="kd">public</span> <span class="kt">void</span> <span class="nf">setUpload</span><span class="o">(</span><span class="n">List</span><span class="o">&lt;</span><span class="n">File</span><span class="o">&gt;</span> <span class="n">uploads</span><span class="o">)</span> <span class="o">{</span>
<span class="k">this</span><span class="o">.</span><span class="na">uploads</span> <span class="o">=</span> <span class="n">uploads</span><span class="o">;</span>
<span class="o">}</span>
<span class="kd">public</span> <span class="n">List</span><span class="o">&lt;</span><span class="n">String</span><span class="o">&gt;</span> <span class="nf">getUploadFileName</span><span class="o">()</span> <span class="o">{</span>
<span class="k">return</span> <span class="k">this</span><span class="o">.</span><span class="na">uploadFileNames</span><span class="o">;</span>
<span class="o">}</span>
<span class="kd">public</span> <span class="kt">void</span> <span class="nf">setUploadFileName</span><span class="o">(</span><span class="n">List</span><span class="o">&lt;</span><span class="n">String</span><span class="o">&gt;</span> <span class="n">uploadFileNames</span><span class="o">)</span> <span class="o">{</span>
<span class="k">this</span><span class="o">.</span><span class="na">uploadFileNames</span> <span class="o">=</span> <span class="n">uploadFileNames</span><span class="o">;</span>
<span class="o">}</span>
<span class="kd">public</span> <span class="n">List</span><span class="o">&lt;</span><span class="n">String</span><span class="o">&gt;</span> <span class="nf">getUploadContentType</span><span class="o">()</span> <span class="o">{</span>
<span class="k">return</span> <span class="k">this</span><span class="o">.</span><span class="na">uploadContentTypes</span><span class="o">;</span>
<span class="o">}</span>
<span class="kd">public</span> <span class="kt">void</span> <span class="nf">setUploadContentType</span><span class="o">(</span><span class="n">List</span><span class="o">&lt;</span><span class="n">String</span><span class="o">&gt;</span> <span class="n">contentTypes</span><span class="o">)</span> <span class="o">{</span>
<span class="k">this</span><span class="o">.</span><span class="na">uploadContentTypes</span> <span class="o">=</span> <span class="n">contentTypes</span><span class="o">;</span>
<span class="o">}</span>
<span class="kd">public</span> <span class="n">String</span> <span class="nf">upload</span><span class="o">()</span> <span class="kd">throws</span> <span class="n">Exception</span> <span class="o">{</span>
<span class="n">System</span><span class="o">.</span><span class="na">out</span><span class="o">.</span><span class="na">println</span><span class="o">(</span><span class="s">"\n\n upload1"</span><span class="o">);</span>
<span class="n">System</span><span class="o">.</span><span class="na">out</span><span class="o">.</span><span class="na">println</span><span class="o">(</span><span class="s">"files:"</span><span class="o">);</span>
<span class="k">for</span> <span class="o">(</span><span class="n">File</span> <span class="n">u</span> <span class="o">:</span> <span class="n">uploads</span><span class="o">)</span> <span class="o">{</span>
<span class="n">System</span><span class="o">.</span><span class="na">out</span><span class="o">.</span><span class="na">println</span><span class="o">(</span><span class="s">"*** "</span> <span class="o">+</span> <span class="n">u</span> <span class="o">+</span> <span class="s">"\t"</span> <span class="o">+</span> <span class="n">u</span><span class="o">.</span><span class="na">length</span><span class="o">());</span>
<span class="o">}</span>
<span class="n">System</span><span class="o">.</span><span class="na">out</span><span class="o">.</span><span class="na">println</span><span class="o">(</span><span class="s">"filenames:"</span><span class="o">);</span>
<span class="k">for</span> <span class="o">(</span><span class="n">String</span> <span class="n">n</span> <span class="o">:</span> <span class="n">uploadFileNames</span><span class="o">)</span> <span class="o">{</span>
<span class="n">System</span><span class="o">.</span><span class="na">out</span><span class="o">.</span><span class="na">println</span><span class="o">(</span><span class="s">"*** "</span> <span class="o">+</span> <span class="n">n</span><span class="o">);</span>
<span class="o">}</span>
<span class="n">System</span><span class="o">.</span><span class="na">out</span><span class="o">.</span><span class="na">println</span><span class="o">(</span><span class="s">"content types:"</span><span class="o">);</span>
<span class="k">for</span> <span class="o">(</span><span class="n">String</span> <span class="n">c</span> <span class="o">:</span> <span class="n">uploadContentTypes</span><span class="o">)</span> <span class="o">{</span>
<span class="n">System</span><span class="o">.</span><span class="na">out</span><span class="o">.</span><span class="na">println</span><span class="o">(</span><span class="s">"*** "</span> <span class="o">+</span> <span class="n">c</span><span class="o">);</span>
<span class="o">}</span>
<span class="n">System</span><span class="o">.</span><span class="na">out</span><span class="o">.</span><span class="na">println</span><span class="o">(</span><span class="s">"\n\n"</span><span class="o">);</span>
<span class="k">return</span> <span class="n">SUCCESS</span><span class="o">;</span>
<span class="o">}</span>
<span class="o">}</span>
</code></pre></div></div>
<h2 id="advanced-configuration">Advanced Configuration</h2>
<p>The Struts 2 <code class="highlighter-rouge">default.properties</code> file defines several settings that affect the behavior of file uploading. You may find in necessary
to change these values. The names and default values are:</p>
<div class="highlighter-rouge"><div class="highlight"><pre class="highlight"><code>struts.multipart.parser=jakarta
struts.multipart.saveDir=
struts.multipart.maxSize=2097152
</code></pre></div></div>
<blockquote>
<p>Please remember that the <code class="highlighter-rouge">struts.multipart.maxSize</code> is the size limit of the whole request, which means when you uploading multiple files,
the sum of their size must be below the <code class="highlighter-rouge">struts.multipart.maxSize</code>!</p>
</blockquote>
<p>In order to change theses settings you define a constant in your applications <code class="highlighter-rouge">struts.xml</code> file like so:</p>
<div class="language-xml highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="cp">&lt;?xml version="1.0" encoding="UTF-8"?&gt;</span>
<span class="cp">&lt;!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd"&gt;</span>
<span class="nt">&lt;struts&gt;</span>
<span class="nt">&lt;constant</span> <span class="na">name=</span><span class="s">"struts.multipart.maxSize"</span> <span class="na">value=</span><span class="s">"1000000"</span> <span class="nt">/&gt;</span>
...
<span class="nt">&lt;/struts&gt;</span>
</code></pre></div></div>
<p>Additionally the <code class="highlighter-rouge">fileUpload</code> interceptor has settings that can be put in place for individual action mappings by customizing your interceptor stack.</p>
<div class="language-xml highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;action</span> <span class="na">name=</span><span class="s">"doUpload"</span> <span class="na">class=</span><span class="s">"com.example.UploadAction"</span><span class="nt">&gt;</span>
<span class="nt">&lt;interceptor-ref</span> <span class="na">name=</span><span class="s">"basicStack"</span><span class="nt">/&gt;</span>
<span class="nt">&lt;interceptor-ref</span> <span class="na">name=</span><span class="s">"fileUpload"</span><span class="nt">&gt;</span>
<span class="nt">&lt;param</span> <span class="na">name=</span><span class="s">"allowedTypes"</span><span class="nt">&gt;</span>text/plain<span class="nt">&lt;/param&gt;</span>
<span class="nt">&lt;/interceptor-ref&gt;</span>
<span class="nt">&lt;interceptor-ref</span> <span class="na">name=</span><span class="s">"validation"</span><span class="nt">/&gt;</span>
<span class="nt">&lt;interceptor-ref</span> <span class="na">name=</span><span class="s">"workflow"</span><span class="nt">/&gt;</span>
<span class="nt">&lt;result</span> <span class="na">name=</span><span class="s">"success"</span><span class="nt">&gt;</span>good_result.jsp<span class="nt">&lt;/result&gt;</span>
<span class="nt">&lt;/action&gt;</span>
</code></pre></div></div>
<h3 id="file-size-limits">File Size Limits</h3>
<p>There are two separate file size limits. First is <code class="highlighter-rouge">struts.multipart.maxSize</code> which comes from the Struts 2 <code class="highlighter-rouge">default.properties</code> file.
This setting exists for security reasons to prohibit a malicious user from uploading extremely large files to file up your servers disk space.
This setting defaults to approximately 2 megabytes and should be adjusted to the maximum size file (2 gigs max) that your will need the framework
to receive. If you are uploading more than one file on a form the <code class="highlighter-rouge">struts.multipart.maxSize</code> applies to the combined total, not the individual
file sizes. The other setting, <code class="highlighter-rouge">maximumSize</code>, is an interceptor setting that is used to ensure a particular Action does not receive a file
that is too large. Notice the locations of both settings in the following example:</p>
<div class="language-xml highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="cp">&lt;?xml version="1.0" encoding="UTF-8"?&gt;</span>
<span class="cp">&lt;!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd"&gt;</span>
<span class="nt">&lt;struts&gt;</span>
<span class="nt">&lt;constant</span> <span class="na">name=</span><span class="s">"struts.multipart.maxSize"</span> <span class="na">value=</span><span class="s">"1000000"</span> <span class="nt">/&gt;</span>
<span class="nt">&lt;action</span> <span class="na">name=</span><span class="s">"doUpload"</span> <span class="na">class=</span><span class="s">"com.example.UploadAction"</span><span class="nt">&gt;</span>
<span class="nt">&lt;interceptor-ref</span> <span class="na">name=</span><span class="s">"basicStack"</span><span class="nt">/&gt;</span>
<span class="nt">&lt;interceptor-ref</span> <span class="na">name=</span><span class="s">"fileUpload"</span><span class="nt">&gt;</span>
<span class="nt">&lt;param</span> <span class="na">name=</span><span class="s">"maximumSize"</span><span class="nt">&gt;</span>500000<span class="nt">&lt;/param&gt;</span>
<span class="nt">&lt;/interceptor-ref&gt;</span>
<span class="nt">&lt;interceptor-ref</span> <span class="na">name=</span><span class="s">"validation"</span><span class="nt">/&gt;</span>
<span class="nt">&lt;interceptor-ref</span> <span class="na">name=</span><span class="s">"workflow"</span><span class="nt">/&gt;</span>
<span class="nt">&lt;result</span> <span class="na">name=</span><span class="s">"success"</span><span class="nt">&gt;</span>good_result.jsp<span class="nt">&lt;/result&gt;</span>
<span class="nt">&lt;/action&gt;</span>
<span class="nt">&lt;/struts&gt;</span>
</code></pre></div></div>
<h3 id="file-types">File Types</h3>
<p>There are two ways to limit the uploaded file type, decoratively and programmatically. To decoratively limit the file type a comma separated
list of allowedTypes can be specified as a fileUpload interceptor param as shown in the following example:</p>
<div class="language-xml highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;action</span> <span class="na">name=</span><span class="s">"doUpload"</span> <span class="na">class=</span><span class="s">"com.example.UploadAction"</span><span class="nt">&gt;</span>
<span class="nt">&lt;interceptor-ref</span> <span class="na">name=</span><span class="s">"basicStack"</span><span class="nt">/&gt;</span>
<span class="nt">&lt;interceptor-ref</span> <span class="na">name=</span><span class="s">"fileUpload"</span><span class="nt">&gt;</span>
<span class="nt">&lt;param</span> <span class="na">name=</span><span class="s">"allowedTypes"</span><span class="nt">&gt;</span>image/jpeg,image/gif<span class="nt">&lt;/param&gt;</span>
<span class="nt">&lt;/interceptor-ref&gt;</span>
<span class="nt">&lt;interceptor-ref</span> <span class="na">name=</span><span class="s">"validation"</span><span class="nt">/&gt;</span>
<span class="nt">&lt;interceptor-ref</span> <span class="na">name=</span><span class="s">"workflow"</span><span class="nt">/&gt;</span>
<span class="nt">&lt;result</span> <span class="na">name=</span><span class="s">"success"</span><span class="nt">&gt;</span>good_result.jsp<span class="nt">&lt;/result&gt;</span>
<span class="nt">&lt;/action&gt;</span>
</code></pre></div></div>
<p>When the uploaded file type does not match one of the MIME types specified a field error will be created as described in the next section
entitled Error Messages. Programmatically limiting the file type means using the information passed in to your Action class via
the <code class="highlighter-rouge">setXContentType(String contentType)</code> method. The benefit to this type of approach would be that it’s more flexible and no interceptor
configuration would be needed if file sizes are keep under 2 megs.</p>
<h3 id="error-messages">Error Messages</h3>
<p>If an error occurs several field errors will be added assuming that the action implements <code class="highlighter-rouge">com.opensymphony.xwork2.ValidationAware</code>
or extends <code class="highlighter-rouge">com.opensymphony.xwork2.ActionSupport</code>. These error messages are based on several i18n values stored in struts-messages.properties,
a default i18n file processed for all i18n requests. You can override the text of these messages by providing text for the following keys:</p>
<table>
<thead>
<tr>
<th>Error Key</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr>
<td><code class="highlighter-rouge">struts.messages.error.uploading</code></td>
<td>A general error that occurs when the file could not be uploaded</td>
</tr>
<tr>
<td><code class="highlighter-rouge">struts.messages.error.file.too.large</code></td>
<td>Occurs when the uploaded file is too large as specified by maximumSize.</td>
</tr>
<tr>
<td><code class="highlighter-rouge">struts.messages.error.content.type.not.allowed</code></td>
<td>Occurs when the uploaded file does not match the expected content types specified</td>
</tr>
<tr>
<td><code class="highlighter-rouge">struts.messages.error.file.extension.not.allowed</code></td>
<td>Occurs when uploaded file has disallowed extension</td>
</tr>
<tr>
<td><code class="highlighter-rouge">struts.messages.upload.error.SizeLimitExceededException</code></td>
<td>Occurs when the upload request (as a whole) exceed configured <strong>struts.multipart.maxSize</strong></td>
</tr>
<tr>
<td><code class="highlighter-rouge">struts.messages.upload.error.&lt;Exception class SimpleName&gt;</code></td>
<td>Occurs when any other exception took place during file upload process</td>
</tr>
</tbody>
</table>
<h3 id="temporary-directories">Temporary Directories</h3>
<p>All uploaded files are saved to a temporary directory by the framework before being passed in to an Action. Depending on the allowed file
sizes it may be necessary to have the framework store these temporary files in an alternate location. To do this change <code class="highlighter-rouge">struts.multipart.saveDir</code>
to the directory where the uploaded files will be placed. If this property is not set it defaults to <code class="highlighter-rouge">javax.servlet.context.tempdir</code>.
Keep in mind that on some operating systems, like Solaris, <code class="highlighter-rouge">/tmp</code> is memory based and files stored in that directory would consume
an amount of RAM approximately equal to the size of the uploaded file.</p>
<h3 id="alternate-libraries">Alternate Libraries</h3>
<p>The <code class="highlighter-rouge">struts.multipart.parser</code> used by the fileUpload interceptor to handle HTTP POST requests, encoded using the MIME-type <code class="highlighter-rouge">multipart/form-data</code>,
can be changed out. Currently there are two choices, jakarta and pell. The jakarta parser is a standard part of the Struts 2 framework needing
only its required libraries added to a project. The pell parser uses Jason Pell’s multipart parser instead of the Commons-FileUpload library.
The pell parser is a Struts 2 plugin, for more details see: <a href="../plugins/pell/">Pell multipart plugin</a>. There was a third alternative, cos, but it was removed
due to licensing incompatibilities.</p>
<p>As from Struts version 2.3.18 a new implementation of <code class="highlighter-rouge">MultiPartRequest</code> was added - <code class="highlighter-rouge">JakartaStreamMultiPartRequest</code>. It can be used to handle
large files, see <a href="https://issues.apache.org/jira/browse/WW-3025">WW-3025</a> for more details, but you can simple set</p>
<div class="highlighter-rouge"><div class="highlight"><pre class="highlight"><code>&lt;constant name="struts.multipart.parser" value="jakarta-stream" /&gt;
</code></pre></div></div>
<p>in struts.xml to start using it.</p>
<h3 id="request-validation">Request validation</h3>
<p>The <code class="highlighter-rouge">struts.multipart.validationRegex</code> is used to define a RegEx to be used to validate if the incoming request is a multipart request.
The request must use the <code class="highlighter-rouge">POST</code> method and match the RegEx, by default the RegEx is defined as follow:</p>
<div class="highlighter-rouge"><div class="highlight"><pre class="highlight"><code>^multipart\\/form-data(; boundary=[a-zA-Z0-9]{1,70})?
</code></pre></div></div>
<p>Please read <a href="https://www.w3.org/Protocols/rfc1341/7\_2\_Multipart.html">RFC1341</a> the <strong>Multipart section</strong> for more details, existing
Struts <code class="highlighter-rouge">Multipart</code> parsers support only <code class="highlighter-rouge">multipart/form-data</code> content type. This option is available since Struts 2.3.11.</p>
<h3 id="disabling-file-upload-support">Disabling file upload support</h3>
<p>You can alternatively disable the whole file upload mechanism defining a constant in <code class="highlighter-rouge">struts.xml</code>:</p>
<div class="language-xml highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;constant</span> <span class="na">name=</span><span class="s">"struts.multipart.enabled"</span> <span class="na">value=</span><span class="s">"false"</span><span class="nt">/&gt;</span>
</code></pre></div></div>
<p>With this constant in place, Struts will ignore a <code class="highlighter-rouge">Content-Type</code> header and will treat each request as an ordinary http request.
This option is available since Struts 2.3.11. </p>
</section>
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