ModelAndView对象未返回到jsp

小编典典

ModelAndView对象未返回到jsp

spring-mvc

我试图从控制器返回一个简单的字符串“ HelloSpring”到jsp。控制器是

package it.polito.ai.e4;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.portlet.ModelAndView;

@Controller
public class HelloSpringController
{
@RequestMapping("/hello")
public ModelAndView helloSpring(HttpServletRequest request,
        HttpServletResponse response)
{
    String message = "HelloSpring";
    return new ModelAndView("hello", "message", message);
}
}

jsp是

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"  "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Hello page</title>
</head>
<body>
    <%=(String)request.getAttribute("message")%>
</body>
</html>

当我在Tomcat 7上执行此操作时，页面正文上出现“ null”字符串。我的web.xml是

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
version="3.0">
<display-name>ai4</display-name>
<servlet>
    <servlet-name>ai4</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
    <servlet-name>ai4</servlet-name>
    <url-pattern>/</url-pattern>
</servlet-mapping>
<welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>

阅读 296

2020-06-01

共1个答案

小编典典

尝试导入org.springframework.web.servlet.ModelAndView而不是org.springframework.web.portlet.ModelAndView。:)

另外，就像Sumit Desai提到的那样，从Spring 3开始，大多数人都这样编写控制器方法：

@RequestMapping("/hello")
public String helloSpring(Model m)
{
    m.addAttribute("message", "HelloSpring");
    return "hello";
}

这只是样式，您所做的也行得通。希望能有所帮助。

2020-06-01