1 前言
上一篇博文介紹了 獲取客戶端數據，本文將介紹作用域傳值，即將數據傳遞給另一個網頁，有以下4種方式：
- 通過 HttpServletRequest 傳值
- 通過 ModelAndView 傳值
- 通過 Map 傳值
- 通過 Model 傳值
注意：Map 和 Model 最終都會轉換爲 ModelAndView 傳給客戶端。
實驗需要導入的 JAR 包如下：
筆者工作目錄如下：
首先介紹下本文各節公共的文件，主要有 web.xml、applicationContext.xml、index.jsp、show.jsp，不同的是 Test.java，將在各節都介紹。
web.xml
<?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"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0">
<!-- 首頁網頁 -->
<welcome-file-list>
<welcome-file>/WEB-INF/view/index.jsp</welcome-file>
</welcome-file-list>
<!-- 配置核心(前端)控制器 DispatcherServlet -->
<servlet>
<servlet-name>dispatcherServlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<!-- 加載IOC容器配置文件 -->
<param-name>contextConfigLocation</param-name>
<param-value>classpath:applicationContext.xml</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>dispatcherServlet</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
<!-- 配置CharacterEncodingFilter，用於解決後臺中文亂碼 -->
<filter>
<filter-name>characterEncodingFilter</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>
<filter-mapping>
<filter-name>characterEncodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
</web-app>
注意：characterEncodingFilter 用於解決客戶端傳遞的中文參數在服務器端亂碼。
applicationContext.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:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd">
<!-- 掃描組件，將加@Controller註解的類作爲SpringMVC的控制層 -->
<context:component-scan base-package="com.test"></context:component-scan>
<!-- 配置視圖解析器 -->
<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/view/"></property>
<property name="suffix" value=".jsp"></property>
</bean>
</beans>
index.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>首頁</title>
</head>
<body>
<form action="user" method="post">
用戶號：<input type="text" name="uid"><br/>
用戶名：<input type="text" name="uname"><br/>
<input type="submit" value="提交"/>
</form>
</body>
</html>
show.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>顯示</title>
</head>
<body>
<h1>
用戶號：${requestScope.uid}<br/>
用戶名：${requestScope.uname}<br/>
</h1>
</body>
</html>
注意：可以省略 requestScope，即：${uid}、${uname}
2 案例分析
2.1 通過 HttpServletRequest 傳值
Test.java
package com.test;
import javax.servlet.http.HttpServletRequest;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
@Controller
public class Test {
@RequestMapping(value="user",method=RequestMethod.POST)
public String addUser(HttpServletRequest request, Integer uid, String uname) {
request.setAttribute("uid", uid);
request.setAttribute("uname",uname);
return "show";
}
}
注意：形參列表中可以不傳 uid、uname，因爲 reques t的 getParameter() 方法可以獲取這些參數。
在地址欄輸入：http://localhost:8080/SpringMVC/，並填寫表單，如下：
提交後，跳轉到 show.jsp 頁面，如下：
2.2 通過 ModelAndView 傳值
Test.java
package com.test;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;
@Controller
public class Test {
@RequestMapping(value="user",method=RequestMethod.POST)
public ModelAndView addUser(Integer uid, String uname) {
ModelAndView mv=new ModelAndView();
mv.addObject("uid",uid);
mv.addObject("uname",uname);
mv.setViewName("show");
return mv;
}
}
2.3 通過 Map 傳值
Test.java
package com.test;
import java.util.Map;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
@Controller
public class Test {
@RequestMapping(value="user",method=RequestMethod.POST)
public String addUser(Map<String,Object> map, Integer uid, String uname) {
map.put("uid",uid);
map.put("uname",uname);
return "show";
}
}
2.4 通過 Model 傳值
Test.java
package com.test;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
@Controller
public class Test {
@RequestMapping(value="user",method=RequestMethod.POST)
public String addUser(Model model, Integer uid, String uname) {
model.addAttribute("uid",uid);
model.addAttribute("uname",uname);
return "show";
}
}