Spring MVC 模型不显示字符串

Question

我的项目是让最终用户登录，然后转到另一个页面显示消息。如果登录详细信息错误，它会显示相应的错误消息，并为他们提供再次登录的机会。问题是，本来应该显示的消息却没有显示。相反，所有显示的是；

Message is: ${message}

index.jsp

<form action="login.html" method="post">
    Name: <input type="text" name="name"/>
    Password: <input type="password" name="password"/>
    <input type="submit" value="submit"/>
</form>

LoginController.java

package com.loginmvc.domain;

@Controller
public class LoginController {

@RequestMapping("/login")
public ModelAndView login(HttpServletRequest req, HttpServletResponse resp) 
    throws ServletException, IOException {

    String name = req.getParameter("name");
    String password = req.getParameter("password");

    if(password.equals("admin")) {          
        String message = "Welcome " + name;
        return new ModelAndView("profilepage", "message", message);
    } else {
        return new ModelAndView("errorpage", "message", 
                "Sorry, the name or password is incorrect.");
    }
  }
}

web.xml

<!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>
  <servlet>
    <servlet-name>spring</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>spring</servlet-name>
    <url-pattern>*.html</url-pattern>
  </servlet-mapping>
</web-app>

spring-servlet.xml

<?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"  
    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">

    <context:component-scan base-package="com.loginmvc.domain" />
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/" />
        <property name="suffix" value=".jsp" />
    </bean>
</beans>

Answer 1

您在 web.xml 文件中使用旧的描述符。这将导致 EL 被忽略:

<!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>

如果您正在学习教程，我建议您找到一个更新的教程。但是，与此同时，更新您的 web.xml 应该可以解决您眼前的问题:

<?xml version="1.0" encoding="UTF-8"?>
<web-app 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_3_0.xsd"
         version="3.0">
...
</web-app>