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POSpring MVC form input value is always null
 

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    <p>I'm new to Spring MVC, but not new to web development in Java. I'm attempting to create a simple form->controller example. </p> <p>I have a form, a form controller (configured in a context XML pasted below) and my model (a simple bean). When I submit the form the value of my text input is always null, regardless. Any ideas?</p> <p>Form controller spring configuration:</p> <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt; &lt;beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"&gt; &lt;!-- controllers --&gt; &lt;bean name="/home.html" class="atc.web.view.controller.HomeController" /&gt; &lt;!--bean name="/mirror.html" class="atc.web.view.controller.MirrorController" --&gt; &lt;bean name="/url-cache.html" class="atc.web.view.controller.URLCacheFormController"&gt; &lt;property name="synchronizeOnSession" value="true" /&gt; &lt;!--property name="sessionForm" value="false"--&gt; &lt;property name="commandName" value="urlForm"/&gt; &lt;property name="commandClass" value="atc.web.view.model.URLBean"/&gt; &lt;property name="validator"&gt; &lt;bean class="atc.web.view.validators.URLValidator"/&gt; &lt;/property&gt; &lt;property name="formView" value="mirror"/&gt; &lt;property name="successView" value="url-cache.html"/&gt; &lt;property name="URLCachingService" ref="urlCachingService" /&gt; &lt;/bean&gt; &lt;!-- end controllers --&gt; &lt;bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"&gt; &lt;property name="viewClass" value="org.springframework.web.servlet.view.JstlView" /&gt; &lt;property name="prefix" value="/WEB-INF/jsp/" /&gt; &lt;property name="suffix" value=".jsp" /&gt; &lt;/bean&gt; &lt;!-- custom beans --&gt; &lt;bean id="breakcrumbInjectionFilter" class="atc.web.view.filter.BreadcrumbInjectionFilter"&gt; &lt;property name="contextPrefix" value="/home-web" /&gt; &lt;/bean&gt; &lt;!-- end custom beans --&gt; &lt;/beans&gt; </code></pre> <p>The JSP that contains my form is as follows:</p> <pre><code>&lt;%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %&gt; &lt;%@ page contentType="text/html;charset=UTF-8" language="java" %&gt; &lt;%@ include file="/WEB-INF/jspf/core/taglibs.jspf" %&gt; &lt;html&gt; &lt;head&gt;&lt;title&gt;Simple tools&lt;/title&gt;&lt;/head&gt; &lt;style&gt; .error s { color:#FF0000; } &lt;/style&gt; &lt;body&gt; &lt;%@ include file="/WEB-INF/jspf/nav/nav.jspf" %&gt; Errors: &lt;form:errors path="url" cssClass="error"/&gt; &lt;form:form method="post" commandName="urlForm"&gt; &lt;form:input path="url" /&gt; &lt;input type="submit" align="center" value="Execute" /&gt; &lt;/form:form&gt; &lt;/body&gt; &lt;/html&gt; </code></pre> <p>Here's the full source of my controller:</p> <pre><code>public class URLCacheFormController extends SimpleFormController { private URLCachingService cachingService; private static Logger log = Logger.getLogger(URLCacheFormController.class); public ModelAndView onSubmit(Object command) throws ServletException { log.debug(String.format("URLCachingFormController received request with object '%s'", command)); URLBean urlBean = (URLBean) command; try { URL url = new URL(urlBean.getUrl()); URLCache cache = cachingService.cacheURL(url); cache.cacheToTempFile(); } catch (IOException e) { log.error("Invalid URL...", e); } return new ModelAndView(new RedirectView(getSuccessView())); } protected Object formBackingObject(HttpServletRequest request) throws ServletException { log.debug("formBackingObject() "); return new URLBean(); } public void setURLCachingService(URLCachingService cachingService) { this.cachingService = cachingService; } } </code></pre> <p>All of the above produces the following HTML:</p> <pre><code>&lt;html&gt; &lt;head&gt;&lt;/head&gt; &lt;body&gt; &lt;div&gt;&lt;span&gt;&lt;a href="home.html"&gt;Home &lt;/a&gt;&lt;/span&gt;&lt;span&gt; | &lt;a href="url-cache.html"&gt;Page Mirror&lt;/a&gt;&lt;/span&gt;&lt;/div&gt; &lt;div id="breadcrumb"&gt;&lt;span&gt;Your trail:&lt;a href=""/&gt;&lt;/span&gt;&lt;/div&gt;Attrs:&lt;div/&gt; &lt;form id="urlForm" method="post" action="/home-web/url-cache.html"&gt; &lt;input id="url" type="text" value="" name="url"/&gt; &lt;input type="submit" align="center" value="Execute"/&gt; &lt;/form&gt; &lt;/body&gt; &lt;/html&gt; </code></pre> <p><strike>I'm now overriding <code>doSubmitAction(Object command)</code> but I still do not hit the method. The form submits but the next thing I know I'm presented with the blank form (after <code>formBackingObject(HttpServletRequest request)</code> is called).</strike></p> <p><strike>That's to say, when I submit, the logging call on line 1 of <code>doSubmitAction</code> in the form controller is never executed.</strike> <strong>The validator executes, and fails (adds error messages correctly) because the value it's checking is always null <em>(or put correctly, it's never set)</em></strong>. The call to <code>formBackingObject</code> always occurs however. The request attribute of my form (the form input 'url') is always null. </p> <p><strong>Update:</strong> OK, so after some serious debugging as suggested by serg555, and removing validation, I can confirm the issue seems to be with mapping the request parameters - such as the value of 'url' from the form - to my command/bean; i.e. the URL is never being set on my bean, or the bean is being recreated.</p> <p>Please help?</p>
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    1. COYou don't show how you've mapped the URL to the controller. Do you have that in your app context? Perhaps you should update your question to show that as well.
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    2. COThe URL mapping is defined in the spring context XML that I've already provided. I've added the rest of the context XML for clarity, however.
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    3. COThis isn't an answer to your question, but you may find it easier to use Spring 2.5-style annotated controllers instead of the old FormCintroller hierarchy. It's considerably simpler and more intuitive.
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