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<a href="index.html" title="back to Getting started"><< back to Getting started</a>
<h1 class="no_toc" id="form-tags">Form Tags</h1>
<ul id="markdown-toc">
<li><a href="#introduction" id="markdown-toc-introduction">Introduction</a></li>
<li><a href="#example-application" id="markdown-toc-example-application">Example Application</a></li>
<li><a href="#struts-2-select-tag" id="markdown-toc-struts-2-select-tag">Struts 2 Select Tag</a></li>
<li><a href="#struts-2-radio-tag" id="markdown-toc-struts-2-radio-tag">Struts 2 Radio Tag</a></li>
<li><a href="#struts-2-select-tag---object-backed" id="markdown-toc-struts-2-select-tag---object-backed">Struts 2 Select Tag - Object Backed</a></li>
<li><a href="#struts-2-checkbox-tag" id="markdown-toc-struts-2-checkbox-tag">Struts 2 Checkbox Tag</a></li>
<li><a href="#struts-2-checkboxlist-tag" id="markdown-toc-struts-2-checkboxlist-tag">Struts 2 checkboxlist Tag</a></li>
<li><a href="#summary" id="markdown-toc-summary">Summary</a></li>
</ul>
<p>The example code for this tutorial, <strong>form-tags</strong>, can be checked out from <a href="https://github.com/apache/struts-examples">struts-examples</a>.</p>
<h2 id="introduction">Introduction</h2>
<p>In this tutorial we’ll explore some of the other Struts 2 form controls. In our previous tutorials that explained how
to use Struts 2 forms (<a href="processing-forms.html">Processing forms</a>, <a href="form-validation.html">Form validation</a>,
and <a href="message-resource-files.html">Message resource files</a> ) we covered how to use the Struts 2 head, form, textfield
controls and the key attribute. This tutorial will explore using the Struts 2 select, radio, checkbox, and checkboxlist
form controls.</p>
<p>The <a href="http://struts.apache.org/mail.html">Struts 2 user mailing list</a> is an excellent place to get help. If you are
having a problem getting the tutorial example applications to work search the Struts 2 mailing list. If you don’t find
an answer to your problem, post a question on the mailing list.</p>
<h2 id="example-application">Example Application</h2>
<p>The example application that supports this tutorial shows how to use Struts 2 form tags so that a user can edit his
information. The information that can be edited is encapsulated in an object of class Person. A Person object knows
these things: first name, last name, favorite sport, gender, state of residency, is or is not over 21, and car models
owned.</p>
<p>To enable the user to edit his information that is stored in the Person object, we need to create a form like this one:</p>
<p><img src="attachments/att19660802_Screen shot 2010-04-25 at 8.39.59 AM.png" alt="Screen shot 2010-04-25 at 8.39.59 AM.png" /></p>
<p>The form allows the user to make changes. After submitting the form, the Struts 2 framework will update the state
of the Person object.</p>
<p>The first and last names are shown on the form (see edit.jsp) using the Struts 2 textfield tag, which we’ve discussed
in previous tutorials.</p>
<h2 id="struts-2-select-tag">Struts 2 Select Tag</h2>
<p>A user can select one favorite sport from several choices. The example application uses the Struts 2 select tag
to provide the list of options for the select box.</p>
<p><strong>Struts 2 Select Tag</strong></p>
<div class="language-html highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;s:select</span> <span class="na">key=</span><span class="s">"personBean.sport"</span> <span class="na">list=</span><span class="s">"sports"</span> <span class="nt">/&gt;</span>
</code></pre></div></div>
<p>In these form tags, we are using the key attribute as discussed in the <a href="message-resource-files.html">Message resource files</a>
tutorial. The key attribute is used by the Struts 2 framework to determine values for the other attributes (e.g. label
and value). We are also using a property file associated with the EditAction class to provide the label values based on
the key attribute value (see the <a href="message-resource-files.html">Message Resource Files</a> tutorial for information on using
Struts 2 property files).</p>
<blockquote>
<p>Note that there are many attributes for the Struts 2 form tags, most of which mirror the HTML attributes associated
with the tags. You can read about all the attributes for a Struts 2 form tag by consulting the Struts 2 documentation.</p>
</blockquote>
<p>The value of the list attribute of the Struts 2 select tag is used by the framework to determine what method
of the action class to call in order to create the option values. In our example application, the list attribute
value of “sports” results in the framework calling the getSports method of class EditAction. That method returns
a String array containing “football”, “baseball”, and “basketball”. Those values are used to create the option tags
inside the select tag.</p>
<p>The Struts 2 framework determines which option is preselected by using the key attribute’s value to call a method
on the personBean object. Since the key attribute’s value is “personBean.sport”, the framework calls the personBean
object’s getSport method. If the value returned by that method matches one of the option values, that option will be
marked as “selected”.</p>
<p>Here is the HTML that results from using the above Struts 2 select tag.</p>
<p><strong>HTML Created By Struts 2 Select Tag</strong></p>
<div class="language-html highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;tr&gt;</span>
<span class="nt">&lt;td</span> <span class="na">class=</span><span class="s">"tdLabel"</span><span class="nt">&gt;</span>
<span class="nt">&lt;label</span> <span class="na">for=</span><span class="s">"save_personBean_sport"</span> <span class="na">class=</span><span class="s">"label"</span><span class="nt">&gt;</span>Favorite sport:<span class="nt">&lt;/label&gt;</span>
<span class="nt">&lt;/td&gt;</span>
<span class="nt">&lt;td&gt;</span>
<span class="nt">&lt;select</span> <span class="na">name=</span><span class="s">"personBean.sport"</span> <span class="na">id=</span><span class="s">"save_personBean_sport"</span><span class="nt">&gt;</span>
<span class="nt">&lt;option</span> <span class="na">value=</span><span class="s">"football"</span><span class="nt">&gt;</span>football<span class="nt">&lt;/option&gt;</span>
<span class="nt">&lt;option</span> <span class="na">value=</span><span class="s">"baseball"</span><span class="nt">&gt;</span>baseball<span class="nt">&lt;/option&gt;</span>
<span class="nt">&lt;option</span> <span class="na">value=</span><span class="s">"basketball"</span> <span class="na">selected=</span><span class="s">"selected"</span><span class="nt">&gt;</span>basketball<span class="nt">&lt;/option&gt;</span>
<span class="nt">&lt;/select&gt;</span>
<span class="nt">&lt;/td&gt;</span>
<span class="nt">&lt;/tr&gt;</span>
</code></pre></div></div>
<p>Note the table formatting created by the Struts 2 framework when using the Struts 2 select tag. The CSS classes are
defined in style sheets included by the Struts 2 s:head tag. The Struts 2 s:head tag is placed inside the edit.jsp’s
head section.</p>
<p>Since the personBean’s getSport method returns “baskeball”, the basketball option value is marked as selected.</p>
<h2 id="struts-2-radio-tag">Struts 2 Radio Tag</h2>
<p>The Struts 2 radio tag—like its standard HTML counterpart—is used to display 2 or more choices, only one of which can
be selected by the user. Here is the code for the Struts 2 radio button from the example application.</p>
<p><strong>Struts 2 Radio Tag</strong></p>
<div class="language-html highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;s:radio</span> <span class="na">key=</span><span class="s">"personBean.gender"</span> <span class="na">list=</span><span class="s">"genders"</span> <span class="nt">/&gt;</span>
</code></pre></div></div>
<p>Again the key attribute’s value determines the value for the label and value attributes. The label’s text is derived
from the EditAction.properties file (key personBean.gender). Just like the Struts 2 select tag, the list attribute
of the Struts 2 radio tag causes the framework to call the getGenders method of the EditAction class.
The Array of String objects returned are used to create the individual radio buttons.</p>
<p><strong>HTML Created By Struts 2 Radio Tag</strong></p>
<div class="language-html highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;tr&gt;</span>
<span class="nt">&lt;td</span> <span class="na">class=</span><span class="s">"tdLabel"</span><span class="nt">&gt;</span>
<span class="nt">&lt;label</span> <span class="na">for=</span><span class="s">"save_personBean_gender"</span> <span class="na">class=</span><span class="s">"label"</span><span class="nt">&gt;</span>Gender:<span class="nt">&lt;/label&gt;</span>
<span class="nt">&lt;/td&gt;</span>
<span class="nt">&lt;td&gt;</span>
<span class="nt">&lt;input</span> <span class="na">type=</span><span class="s">"radio"</span> <span class="na">name=</span><span class="s">"personBean.gender"</span> <span class="na">id=</span><span class="s">"save_personBean_gendermale"</span> <span class="na">value=</span><span class="s">"male"</span><span class="nt">/&gt;</span>
<span class="nt">&lt;label</span> <span class="na">for=</span><span class="s">"save_personBean_gendermale"</span><span class="nt">&gt;</span>male<span class="nt">&lt;/label&gt;</span>
<span class="nt">&lt;input</span> <span class="na">type=</span><span class="s">"radio"</span> <span class="na">name=</span><span class="s">"personBean.gender"</span> <span class="na">id=</span><span class="s">"save_personBean_genderfemale"</span> <span class="na">value=</span><span class="s">"female"</span><span class="nt">/&gt;</span>
<span class="nt">&lt;label</span> <span class="na">for=</span><span class="s">"save_personBean_genderfemale"</span><span class="nt">&gt;</span>female<span class="nt">&lt;/label&gt;</span>
<span class="nt">&lt;input</span> <span class="na">type=</span><span class="s">"radio"</span> <span class="na">name=</span><span class="s">"personBean.gender"</span> <span class="na">id=</span><span class="s">"save_personBean_gendernot sure"</span> <span class="na">checked=</span><span class="s">"checked"</span> <span class="na">value=</span><span class="s">"not sure"</span><span class="nt">/&gt;</span>
<span class="nt">&lt;label</span> <span class="na">for=</span><span class="s">"save_personBean_gendernot sure"</span><span class="nt">&gt;</span>not sure<span class="nt">&lt;/label&gt;</span>
<span class="nt">&lt;/td&gt;</span>
<span class="nt">&lt;/tr&gt;</span>
</code></pre></div></div>
<p>Also just like the Struts 2 select tag the result returned by calling the personBean object’s getGender method is used
to determine which of the radio buttons is checked.</p>
<h2 id="struts-2-select-tag---object-backed">Struts 2 Select Tag - Object Backed</h2>
<p>You may need to create a Struts 2 select tag where the options displayed to the user each have their own value that is
different from what is displayed. In the example application, the user’s residency is stored as a two-letter
abbreviation (e.g. KS), but the form select box should display the full state name (e.g. Kansas). To create such
a select box in Struts 2, you would use this code</p>
<p><strong>Struts 2 Select Tag Object Backed</strong></p>
<div class="language-html highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;s:select</span> <span class="na">key=</span><span class="s">"personBean.residency"</span> <span class="na">list=</span><span class="s">"states"</span> <span class="na">listKey=</span><span class="s">"stateAbbr"</span> <span class="na">listValue=</span><span class="s">"stateName"</span> <span class="nt">/&gt;</span>
</code></pre></div></div>
<p>The list value tells the framework to call the getStates method of the EditAction class. That method returns
an ArrayList of State objects. Each State object has getStateAbbr and getStateName methods.</p>
<p>The listKey attribute tells the framework to use the value returned by calling the getStateAbbr method as the value for
the value attribute of the HTML option tag and the value returned by calling the getStateName method as the value
displayed to the user. So the above Struts 2 select tag code results in this HTML.</p>
<p><strong>HTML Created By Struts 2 Select Tag</strong></p>
<div class="language-html highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;tr&gt;</span>
<span class="nt">&lt;td</span> <span class="na">class=</span><span class="s">"tdLabel"</span><span class="nt">&gt;</span>
<span class="nt">&lt;label</span> <span class="na">for=</span><span class="s">"save_personBean_residency"</span> <span class="na">class=</span><span class="s">"label"</span><span class="nt">&gt;</span>State resident:<span class="nt">&lt;/label&gt;</span>
<span class="nt">&lt;/td&gt;</span>
<span class="nt">&lt;td&gt;</span>
<span class="nt">&lt;select</span> <span class="na">name=</span><span class="s">"personBean.residency"</span> <span class="na">id=</span><span class="s">"save_personBean_residency"</span><span class="nt">&gt;</span>
<span class="nt">&lt;option</span> <span class="na">value=</span><span class="s">"AZ"</span><span class="nt">&gt;</span>Arizona<span class="nt">&lt;/option&gt;</span>
<span class="nt">&lt;option</span> <span class="na">value=</span><span class="s">"CA"</span><span class="nt">&gt;</span>California<span class="nt">&lt;/option&gt;</span>
<span class="nt">&lt;option</span> <span class="na">value=</span><span class="s">"FL"</span><span class="nt">&gt;</span>Florida<span class="nt">&lt;/option&gt;</span>
<span class="nt">&lt;option</span> <span class="na">value=</span><span class="s">"KS"</span> <span class="na">selected=</span><span class="s">"selected"</span><span class="nt">&gt;</span>Kansas<span class="nt">&lt;/option&gt;</span>
<span class="nt">&lt;option</span> <span class="na">value=</span><span class="s">"NY"</span><span class="nt">&gt;</span>New York<span class="nt">&lt;/option&gt;</span>
<span class="nt">&lt;/select&gt;</span>
<span class="nt">&lt;/td&gt;</span>
<span class="nt">&lt;/tr&gt;</span>
</code></pre></div></div>
<p>The value returned by calling the personBean object’s getResidency method determines which of the select tag’s option
tags is marked as selected. In our example, since getResidency returns “KS”, the option tag whose value attribute
equals “KS” is marked as selected.</p>
<h2 id="struts-2-checkbox-tag">Struts 2 Checkbox Tag</h2>
<p>The Struts 2 checkbox tag is used to create the HTML input type equals checkbox tag. The value for the key attribute
tells the framework what method to call to determine if the checkbox is checked or not checked. The method called should
return a Boolean value (true or false). A return value of true will cause the checkbox to be checked and false
the checkbox will not be checked.</p>
<p><strong>Struts 2 Checkbox Tag</strong></p>
<div class="language-html highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;s:checkbox</span> <span class="na">key=</span><span class="s">"personBean.over21"</span> <span class="nt">/&gt;</span>
</code></pre></div></div>
<p>Since the method isOver21 returns true, the checkbox is checked.</p>
<p><strong>HTML Created By Struts 2 Checkbox Tag</strong></p>
<div class="language-html highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;tr&gt;</span>
<span class="nt">&lt;td</span> <span class="na">valign=</span><span class="s">"top"</span> <span class="na">align=</span><span class="s">"right"</span><span class="nt">&gt;&lt;/td&gt;</span>
<span class="nt">&lt;td</span> <span class="na">valign=</span><span class="s">"top"</span> <span class="na">align=</span><span class="s">"left"</span><span class="nt">&gt;</span>
<span class="nt">&lt;input</span> <span class="na">type=</span><span class="s">"checkbox"</span> <span class="na">name=</span><span class="s">"personBean.over21"</span> <span class="na">value=</span><span class="s">"true"</span> <span class="na">checked=</span><span class="s">"checked"</span> <span class="na">id=</span><span class="s">"save_personBean_over21"</span><span class="nt">/&gt;</span>
<span class="nt">&lt;input</span> <span class="na">type=</span><span class="s">"hidden"</span> <span class="na">id=</span><span class="s">"__checkbox_save_personBean_over21"</span> <span class="na">name=</span><span class="s">"__checkbox_personBean.over21"</span> <span class="na">value=</span><span class="s">"true"</span> <span class="nt">/&gt;</span>
<span class="nt">&lt;label</span> <span class="na">for=</span><span class="s">"save_personBean_over21"</span> <span class="na">class=</span><span class="s">"checkboxLabel"</span><span class="nt">&gt;</span>21 or older<span class="nt">&lt;/label&gt;</span>
<span class="nt">&lt;/td&gt;</span>
<span class="nt">&lt;/tr&gt;</span>
</code></pre></div></div>
<p>When the form is submitted and the checkbox is not checked, no value will be posted for the checkbox (this is how HTML
forms work). Since the Struts 2 framework will need to update the value of the personBean’s over21 instance field
to false—given that the check box was not checked—the framework needs a way to determine if the checkbox was not checked
after form submission.</p>
<p>If you examine the HTML code created by the Struts 2 checkbox tag, you’ll see that it created a hidden field associated
with the personBean.over21 checkbox. When the Struts 2 framework intercepts the submission of this form it will use this
hidden form field to check if the associated checkbox field exists in the posted form data. If that checkbox field
doesn’t exist then the Struts 2 framework will know to update the value of the personBean object’s over21 instance
variable to false.</p>
<h2 id="struts-2-checkboxlist-tag">Struts 2 checkboxlist Tag</h2>
<p>The Struts 2 framework provides a unique form field control that creates a series of associated check boxes, one or more
of which can be checked. In the example application, the Person class has an Array of Strings, which is used to store
car models owned by a person.</p>
<p>Using the Struts 2 checkbox tag, we can create a series of checkboxes, one for each possible car model the user may own.
The value of each String in the personBean’s carModels Array will determine which checkboxes are checked.</p>
<p><strong>Struts 2 Checkboxlist Tag</strong></p>
<div class="language-html highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;s:checkboxlist</span> <span class="na">key=</span><span class="s">"personBean.carModels"</span> <span class="na">list=</span><span class="s">"carModelsAvailable"</span> <span class="nt">/&gt;</span>
</code></pre></div></div>
<p>The list attributes value in the checkboxlist tag tells the Struts 2 framework which method to call to get the possible
car models. In the example application, the framework will call the EditAction class’s getCarModelsAvailable method.
That method returns an Array of Strings. For each element of the Array, the Struts 2 framework creates a checkbox
(including the associated hidden field described above).</p>
<p>The key attribute value in the checkboxlist tag tells the Struts 2 framework which method to call on the personBean
object to determine which checkboxes should be checked. In the example application, the framework will call
the personBean object’s getCarModels method. The getCarModels method returns an Array of Strings. For each String value
in that Array that matches a String value in the Array returned by the EditAction class’s getCarModelsAvailable,
the checkbox will be checked.</p>
<p><strong>HTML Created By Struts 2 Checkboxlist Tag</strong></p>
<div class="language-html highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;tr&gt;</span>
<span class="nt">&lt;td</span> <span class="na">class=</span><span class="s">"tdLabel"</span><span class="nt">&gt;</span>
<span class="nt">&lt;label</span> <span class="na">for=</span><span class="s">"save_personBean_carModels"</span> <span class="na">class=</span><span class="s">"label"</span><span class="nt">&gt;</span>Car models owned:<span class="nt">&lt;/label&gt;</span>
<span class="nt">&lt;/td&gt;</span>
<span class="nt">&lt;td&gt;</span>
<span class="nt">&lt;input</span> <span class="na">type=</span><span class="s">"checkbox"</span> <span class="na">name=</span><span class="s">"personBean.carModels"</span> <span class="na">value=</span><span class="s">"Ford"</span> <span class="na">id=</span><span class="s">"personBean.carModels-1"</span> <span class="na">checked=</span><span class="s">"checked"</span><span class="nt">/&gt;</span>
<span class="nt">&lt;label</span> <span class="na">for=</span><span class="s">"personBean.carModels-1"</span> <span class="na">class=</span><span class="s">"checkboxLabel"</span><span class="nt">&gt;</span>Ford<span class="nt">&lt;/label&gt;</span>
<span class="nt">&lt;input</span> <span class="na">type=</span><span class="s">"checkbox"</span> <span class="na">name=</span><span class="s">"personBean.carModels"</span> <span class="na">value=</span><span class="s">"Chrysler"</span> <span class="na">id=</span><span class="s">"personBean.carModels-2"</span><span class="nt">/&gt;</span>
<span class="nt">&lt;label</span> <span class="na">for=</span><span class="s">"personBean.carModels-2"</span> <span class="na">class=</span><span class="s">"checkboxLabel"</span><span class="nt">&gt;</span>Chrysler<span class="nt">&lt;/label&gt;</span>
<span class="nt">&lt;input</span> <span class="na">type=</span><span class="s">"checkbox"</span> <span class="na">name=</span><span class="s">"personBean.carModels"</span> <span class="na">value=</span><span class="s">"Toyota"</span> <span class="na">id=</span><span class="s">"personBean.carModels-3"</span><span class="nt">/&gt;</span>
<span class="nt">&lt;label</span> <span class="na">for=</span><span class="s">"personBean.carModels-3"</span> <span class="na">class=</span><span class="s">"checkboxLabel"</span><span class="nt">&gt;</span>Toyota<span class="nt">&lt;/label&gt;</span>
<span class="nt">&lt;input</span> <span class="na">type=</span><span class="s">"checkbox"</span> <span class="na">name=</span><span class="s">"personBean.carModels"</span> <span class="na">value=</span><span class="s">"Nissan"</span> <span class="na">id=</span><span class="s">"personBean.carModels-4"</span> <span class="na">checked=</span><span class="s">"checked"</span><span class="nt">/&gt;</span>
<span class="nt">&lt;label</span> <span class="na">for=</span><span class="s">"personBean.carModels-4"</span> <span class="na">class=</span><span class="s">"checkboxLabel"</span><span class="nt">&gt;</span>Nissan<span class="nt">&lt;/label&gt;</span>
<span class="nt">&lt;input</span> <span class="na">type=</span><span class="s">"hidden"</span> <span class="na">id=</span><span class="s">"__multiselect_save_personBean_carModels"</span> <span class="na">name=</span><span class="s">"__multiselect_personBean.carModels"</span> <span class="na">value=</span><span class="s">""</span> <span class="nt">/&gt;</span>
<span class="nt">&lt;/td&gt;</span>
<span class="nt">&lt;/tr&gt;</span>
</code></pre></div></div>
<h2 id="summary">Summary</h2>
<p>There are several other Struts 2 form controls you should explore. If you need more information about the Struts 2 form
tags consult the Struts 2 documentation at <a href="http://struts.apache.org">http://struts.apache.org</a>.</p>
<table>
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<td>Return to <a href="debugging-struts.html">Debugging Struts</a></td>
<td>or</td>
<td>onward to <a href="form-validation-using-xml.html">Form validation using XML</a></td>
</tr>
</tbody>
</table>
</section>
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