SpringMVC中JSP取不到ModelAndView的数据原因

最新推荐文章于 2022-10-28 15:54:09 发布

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在项目中发现用JSP取不到ModelAndView的数据,但能跳转到对应的页面，显示$("message"),而非对应的值

找了半天原因,发现在web.xml的配置有问题：

原配置为：

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >
<web-app>

当改成这样就可以了：

<?xml version="1.0" encoding="UTF-8"?>

<web-app version="2.5"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

没想到与web.xml的配置有关系。原web.xml是我建立项目用maven生成的。

可以看下：http://forum.springsource.org/showthread.php?117394-Unable-to-access-modelAndView-attributes-in-JSP-without-JSTL

还有一个原因：

一个可能是你实现了HandlerInterceptor并实现了：
void postHandle(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, java.lang.Object o, org.springframework.web.servlet.ModelAndView modelAndView) throws java.lang.Exception;

在此处修改了modelAndView

这个是网上找的（http://www.blogjava.net/javagrass/archive/2012/12/17/393107.html）

解决方法:

按照标准用法的话应该是没问题
内部其实把model 通过request.setAttribute(modelName, modelValue); 放入的

    protected void exposeModelAsRequestAttributes(Map<String, Object> model, HttpServletRequest request) throws Exception {
       for (Map.Entry<String, Object> entry : model.entrySet()) {
           String modelName = entry.getKey();
           Object modelValue = entry.getValue();
           if (modelValue != null) {
               request.setAttribute(modelName, modelValue);
               if (logger.isDebugEnabled()) {
                   logger.debug("Added model object '" + modelName + "' of type [" + modelValue.getClass().getName() +
                           "] to request in view with name '" + getBeanName() + "'");
               }
           }
           else {
               request.removeAttribute(modelName);
               if (logger.isDebugEnabled()) {
                   logger.debug("Removed model object '" + modelName +
                           "' from request in view with name '" + getBeanName() + "'");
               }
           }
       }
   }

当然还有其他配置不能忘了：

 <display-name>dk</display-name>
      <filter>
        <filter-name>encodingFilter</filter-name>
        <filter-class>
            org.springframework.web.filter.CharacterEncodingFilter
        </filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
        <init-param>
            <param-name>forceEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>
    
  <servlet>
        <servlet-name>spring</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath*:config/SpringMVC*.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>        
 
    <servlet-mapping>
        <servlet-name>spring</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>default</servlet-name>
        <url-pattern>*.html</url-pattern>
    </servlet-mapping>

SpringMVC_servlet.xml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" xmlns:p="http://www.springframework.org/schema/p"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:mvc="http://www.springframework.org/schema/mvc"
	xsi:schemaLocation="     
           http://www.springframework.org/schema/beans     
           http://www.springframework.org/schema/beans/spring-beans-3.0.xsd     
           http://www.springframework.org/schema/context     
           http://www.springframework.org/schema/context/spring-context-3.0.xsd    
           http://www.springframework.org/schema/mvc     
           http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">

	<!-- ViewResolver -->
	<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/page/" />
		<property name="suffix" value=".jsp" />
	</bean>
	<context:component-scan base-package="com.dk.*.controller" />
	<mvc:annotation-driven />
</beans>

当然jsp中也少不了这句：

 <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

pom.xml

<dependencies>
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>3.8.1</version>
			<scope>test</scope>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-web</artifactId>
			<version>3.2.8.RELEASE</version>
		</dependency>

		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-webmvc</artifactId>
			<version>3.2.8.RELEASE</version>
		</dependency>
              <!--jstl-->
		<dependency>
			<groupId>javax.servlet</groupId>
			<artifactId>jstl</artifactId>
			<version>1.2</version>
		</dependency>
	</dependencies>