SpringMVC重定向传递参数

在SpringMVC的一个controller中要把参数传到页面，只要配置视图解析器，把参数添加到Model中，在页面用el表达式就可以取到。但是，这样使用的是forward方式，浏览器的地址栏是不变的，如果这时候浏览器F5刷新，就会造成表单重复提交的情况。所以，我们可以使用重定向的方式，改变浏览器的地址栏，防止表单因为刷新重复提交。

WEB-INF下web.xml文件：

<!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>
  <display-name>Archetype Created Web Application</display-name>
  
    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>
            org.springframework.web.servlet.DispatcherServlet
        </servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

WEB-INF下springmvc-servlet文件：

<?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:context="http://www.springframework.org/schema/context" 
       xmlns:mvc="http://www.springframework.org/schema/mvc" 
       xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd 
       http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd 
       http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd"> 
    <mvc:annotation-driven />
    <context:component-scan base-package="com" /> 
    <bean id="irViewResolver"
        class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/page/" /> 
        <property name="suffix" value=".jsp" />
</beans>

*视图定位：作用是把视图约定在 webapp/page/*.jsp 这个位置

JSP文件：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8" isELIgnored="false"%>
 
<h1>${message}</h1>

<form action="addProduct">
 
    产品名称 ：<input type="text" name="name" value=""><br />
    产品价格： <input type="text" name="price" value=""><br />
 
    <input type="submit" value="增加商品">
</form>

Controller：

package com;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.mvc.support.RedirectAttributes;

import pojo.Product;

@Controller
public class IndexController{
    
    @RequestMapping("/addProduct")
    public String add(Product product, RedirectAttributes model){
        model.addFlashAttribute("name", product.getName());
        return "redirect:/showProduct";        
    }
    
    @RequestMapping("/showProduct")
    public String show(@ModelAttribute("name") String name, Model model){    
        System.out.println(name);
        model.addAttribute("name", name);
        return "show";
    }
}

*自动装箱：add方法里面准备一个Product参数，会自动获取表单提交数据

package pojo;
 
public class Product {
 
    private int id;
    private String name;
    private float price;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public float getPrice() {
        return price;
    }
    public void setPrice(float price) {
        this.price = price;
    }
     
}

 出现的问题：

java.lang.IllegalStateException: Argument [RedirectAttributes] is of type Model or Map but is not assignable from the actual model. You may need to switch newer MVC infrastructure classes to use this argument. 

解决：在springmvc-servlet.xml中

<?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:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc" 
xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd 
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd 
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd"> 

并加上这个标签：<mvc:annotation-driven />