JSTL表达式的有关问题

		<taglib>
			<taglib-uri>/WEB-INF/core.tld</taglib-uri>
			<taglib-location>/WEB-INF/tld/c.tld</taglib-location>
		</taglib>

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" 
	xmlns="http://java.sun.com/xml/ns/j2ee" 
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 
	http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
	<servlet>
   <servlet-name>web</servlet-name>  
   <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
   <load-on-startup>2</load-on-startup>
   </servlet>


 <servlet-mapping>
 <servlet-name>web</servlet-name>
 <url-pattern>*.htm</url-pattern>
 </servlet-mapping>

 <servlet>
 <servlet-name>context</servlet-name>
 <servlet-class>org.springframework.web.context.ContextLoaderServlet</servlet-class>
 <load-on-startup>1</load-on-startup>
 </servlet>


 <context-param>
 <param-name>contextConfigLocation</param-name>
 <param-value>/WEB-INF/applicationContext.xml</param-value>
 </context-param>
<welcome-file-list>
    <welcome-file>
      login.jsp
    </welcome-file>
  </welcome-file-list>	
 <taglib>
    <taglib-uri>/spring</taglib-uri>
    <taglib-location>/WEB-INF/spring.tld</taglib-location>
  </taglib>
  
  <taglib>
    <taglib-uri>/WEB-INF/c.tld</taglib-uri>
    <taglib-location>/WEB-INF/c.tld</taglib-location>
  </taglib>
  
  
  <taglib>
    <taglib-uri>/WEB-INF/fmt.tld</taglib-uri>
    <taglib-location>/WEB-INF/fmt.tld</taglib-location>
  </taglib>
</web-app>

String error = (String)request.getAttribute("error");
<%=error%>

/**
 * 
 */
package web;

import java.util.HashMap;

import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.SimpleFormController;
import org.springframework.web.servlet.view.RedirectView;

import pojo.Tusers;
import service.UserService;

/**
 * @author Administrator
 *
 */
public class FormController extends SimpleFormController {
	
	private UserService userservice;
	private String fail_view;
	private String success_view;
	protected ModelAndView onSubmit(Object command) throws Exception{
		Tusers tt = (Tusers)command;
		System.out.println("userName: "+tt.getUserName());
		System.out.println("password: "+tt.getPassword());
		HashMap hm = new HashMap();
		try
		{
			userservice.checkLogin(tt);
			
			hm.put("userName", tt.getUserName());
		}
		catch(RuntimeException e)
		{
			hm.put("error", e.getMessage());
			System.out.println(e);
//			return new ModelAndView(new RedirectView(this.getFail_view()),hm);
			return new ModelAndView(this.getFail_view(),hm);
		}
		
		return new ModelAndView(this.getSuccess_view(),hm);
	}
	/**
	 * @return the userservice
	 */
	public UserService getUserservice() {
		return userservice;
	}
	/**
	 * @param userservice the userservice to set
	 */
	public void setUserservice(UserService userservice) {
		this.userservice = userservice;
	}
	/**
	 * @return the fail_view
	 */
	public String getFail_view() {
		return fail_view;
	}
	/**
	 * @param fail_view the fail_view to set
	 */
	public void setFail_view(String fail_view) {
		this.fail_view = fail_view;
	}
	/**
	 * @return the success_view
	 */
	public String getSuccess_view() {
		return success_view;
	}
	/**
	 * @param success_view the success_view to set
	 */
	public void setSuccess_view(String success_view) {
		this.success_view = success_view;
	}

}

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">

<beans>
	<bean id="FormController" class="web.FormController">
        <property name="sessionForm"><value>true</value></property>
        <property name="commandName"><value>user</value></property>
        <property name="commandClass"><value>pojo.Tusers</value></property>
        <property name="formView"><value>login</value></property>
        <property name="fail_view">  
			<value>fail</value> 
		</property> 
		<property name="success_view"> 
        	<value>ok</value>
		</property> 
        <property name="userservice">
			<ref bean="userService" />
		</property>
    </bean>
    <bean id="urlMapping" class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping"> 
        <property name="mappings">
            <props>
                <prop key="/login.htm">FormController</prop>
            </props>
        </property>
    </bean>
    <bean id="viewResolver" class = "org.springframework.web.servlet.view.InternalResourceViewResolver">
	<property name="viewClass"><value>org.springframework.web.servlet.view.JstlView</value></property>
	<property name ="prefix"><value>/WEB-INF/</value></property>
	<property name ="suffix"><value>.jsp</value></property>
</bean>
</beans>