我是 Spring MVC 的新手，但不是 Java 网络开发的新手。我正在尝试创建一个简单的 form->controller 示例。
我有一个表单、一个表单 Controller (在下面粘贴的上下文 XML 中配置)和我的模型(一个简单的 bean)。当我提交表单时，无论如何，我的文本输入值始终为空。有什么想法吗？
表单 Controller Spring 配置:
<?xml version="1.0" encoding="UTF-8"?>
<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">
<!-- controllers -->
<bean name="/home.html" class="atc.web.view.controller.HomeController" />
<!--bean name="/mirror.html" class="atc.web.view.controller.MirrorController" -->
<bean name="/url-cache.html" class="atc.web.view.controller.URLCacheFormController">
<property name="synchronizeOnSession" value="true" />
<!--property name="sessionForm" value="false"-->
<property name="commandName" value="urlForm"/>
<property name="commandClass" value="atc.web.view.model.URLBean"/>
<property name="validator">
<bean class="atc.web.view.validators.URLValidator"/>
</property>
<property name="formView" value="mirror"/>
<property name="successView" value="url-cache.html"/>
<property name="URLCachingService" ref="urlCachingService" />
</bean>
<!-- end controllers -->
<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="viewClass" value="org.springframework.web.servlet.view.JstlView" />
<property name="prefix" value="/WEB-INF/jsp/" />
<property name="suffix" value=".jsp" />
</bean>
<!-- custom beans -->
<bean id="breakcrumbInjectionFilter" class="atc.web.view.filter.BreadcrumbInjectionFilter">
<property name="contextPrefix" value="/home-web" />
</bean>
<!-- end custom beans -->
</beans>
包含我的表单的 JSP 如下:
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ include file="/WEB-INF/jspf/core/taglibs.jspf" %>
<html>
<head><title>Simple tools</title></head>
<style>
.error s {
color:#FF0000;
}
</style>
<body>
<%@ include file="/WEB-INF/jspf/nav/nav.jspf" %>
Errors: <form:errors path="url" cssClass="error"/>
<form:form method="post" commandName="urlForm">
<form:input path="url" />
<input type="submit" align="center" value="Execute" />
</form:form>
</body>
</html>
这是我的 Controller 的完整源代码:
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;
}
}
以上所有内容生成以下 HTML:
<html>
<head></head>
<body>
<div><span><a href="home.html">Home </a></span><span> | <a href="url-cache.html">Page Mirror</a></span></div>
<div id="breadcrumb"><span>Your trail:<a href=""/></span></div>Attrs:<div/>
<form id="urlForm" method="post" action="/home-web/url-cache.html">
<input id="url" type="text" value="" name="url"/>
<input type="submit" align="center" value="Execute"/>
</form>
</body>
</html>
我现在正在覆盖 doSubmitAction(Object command) 但我仍然没有点击该方法。表单已提交，但接下来我知道我看到的是空白表单(在调用 formBackingObject(HttpServletRequest request) 之后)。
也就是说，当我提交时，表单 Controller 中 validator 执行，但失败(正确添加错误消息)因为它检查的值始终为 null (或正确放置，它从未设置)。但是，总是会调用 doSubmitAction 第 1 行的日志记录调用永远不会执行。formBackingObject。我的表单的请求属性(表单输入“url”)始终为空。
更新: 好的，在按照 serg555 的建议进行一些认真的调试并删除验证之后，我可以确认问题似乎与映射请求参数有关 - 例如“url”的值从表单到我的命令/bean；即从未在我的 bean 上设置 URL，或者正在重新创建 bean。
请帮忙？
最佳答案
我不知道问题出在哪里，让我给你看我的 Controller ，也许你能找出问题所在:
public class TestController extends SimpleFormController {
public TestController () {
setFormView("testView");
setSuccessView("testView");
setCommandClass(TestCmd.class);
setCommandName("cmd");
}
protected Object formBackingObject(HttpServletRequest request)throws Exception {
Object o = super.formBackingObject(request);
TestCmd cmd = (TestCmd) o;
return cmd;
}
public ModelAndView onSubmit(HttpServletRequest request, HttpServletResponse response, Object obj, BindException errors) throws Exception {
TestCmd cmd = (TestCmd) obj;
log.debug("test value = " + cmd.getTestValue());
return super.onSubmit(request, response, obj, errors);
}
}
表格:
<form method="post" action="/test.html">
<form:input path="cmd.testValue"/>
<input type="submit">
</form>
在 App-servlet.xml 中:
<bean id="urlMapping"
class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
<property name="alwaysUseFullPath" value="true" />
<property name="mappings">
<props>
<prop key="/test.html">testController</prop>
</props>
</property>
</bean>
<bean id="testController"
class="com.sample.TestController">
<property name="synchronizeOnSession" value="true" />
<property name="validator">
<bean class="com.sample.TestValidator"/>
</property>
</bean>
validator :
public class TestValidator implements Validator {
public boolean supports(Class clazz) {
return (TestCmd.class.equals(clazz));
}
public void validate(Object obj, Errors errors) {
TestCmd cmd = (TestCmd) obj;
if (obj == null) {
// nothing
} else {
ValidationUtils.rejectIfEmptyOrWhitespace(errors, "testValue", null, "<b>Value</b> is required");
}
}
}
命令:
public class TestCmd {
private String testValue;
public TestCmd() {
}
public String getTestValue() {
return testValue;
}
public void setTestValue(String testValue) {
this.testValue = testValue;
}
}
关于java - Spring MVC 表单输入值始终为空，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/1052594/