JSP在Spring中不显示模型中的对象


问题内容

我有一个容易解决的问题,但我没有运气。

在我的servlet-servlet.xml文件中,我有以下bean(除了其他bean):

<bean id="viewResolver"
    class="org.springframework.web.servlet.view.UrlBasedViewResolver">
    <property name="viewClass" value="org.springframework.web.servlet.view.JstlView" />
    <property name="prefix" value="/WEB-INF/jsp/" />
    <property name="suffix" value=".jsp" />
</bean>

<context:component-scan base-package="com.servlet.web" />

我的测试控制器如下所示:

package com.servlet.web;

import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class TestController
{
    protected final Log log = LogFactory.getLog(getClass());

    @RequestMapping("/test")
     public String methodName(Map<String, Object> map) {
         map.put("someMessage", "some string here");
         return "test";
     }

}

我的jsp视图如下所示:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<title>servlet.com</title>
</head>
<body>
${someMessage}
</body>
</html>

因此,当我查看jsp时,我希望有someMessage的值(这里是一些字符串),但是我只能得到以下内容:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<title>servlet.com</title>
</head>
<body>
${someMessage}

</body>
</html>

当我增加日志记录时,我看到我的someMessage对象被放置在模型中:

22:21:17,425 DEBUG DispatcherServlet:852 - DispatcherServlet with name 'servlet' determining Last-Modified value for [/servlet/access/test]
22:21:17,426 DEBUG DefaultAnnotationHandlerMapping:183 - Mapping [/test] to handler 'com.servlet.web.TestController@762fef'
22:21:17,426 DEBUG DispatcherServlet:868 - Last-Modified value for [/servlet/access/test] is: -1
22:21:17,426 DEBUG DispatcherServlet:700 - DispatcherServlet with name 'servlet' processing GET request for [/servlet/access/test]
22:21:17,427 DEBUG HandlerMethodInvoker:158 - Invoking request handler method: public java.lang.String com.servlet.web.TestController.methodName(java.util.Map)
22:21:17,427 DEBUG DispatcherServlet:1070 - Rendering view [org.springframework.web.servlet.view.JstlView: name 'test'; URL [/WEB-INF/jsp/test.jsp]] in DispatcherServlet with name 'servlet'
22:21:17,427 DEBUG JstlView:328 - Added model object 'someMessage' of type [java.lang.String] to request in view with name 'test'
22:21:17,428 DEBUG JstlView:237 - Forwarding to resource [/WEB-INF/jsp/test.jsp] in InternalResourceView 'test'
22:21:17,429 DEBUG DispatcherServlet:666 - Successfully completed request

显然,我的视图已正确映射,但是我似乎无法访问视图中添加到请求中的模型对象。过去,我已经使用Spring
MVC进行过多次此类操作,但是在这里我肯定会遗漏一些明显的内容。有任何想法吗?谢谢。


问题答案:

您确定在JSP中启用了EL评估吗?有时我有一个问题,那就是某种原因。尝试评估一个简单的表达式,例如${'test'},看看是否出现“ test”。

您也可以尝试使用页面指令或如果要禁用EL的其他方式来启用它。

<%@ page isScriptingEnabled="true" isELIgnored="false" %> //of course it has to be FALSE

(对不起,我不记得这是否100%正确。它可能是’isELEnabled’)