Spring MVC（三）控制器获取页面请求参数以及将控制器数据传递给页面和实现重定向的方式

首先做好环境配置

在mvc.xml里进行配置

　　1.开启组件扫描

　　2.开启基于mvc的标注

　　3.配置试图处理器

 <?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:lang="http://www.springframework.org/schema/lang"
     xmlns:mvc="http://www.springframework.org/schema/mvc"
     xmlns:util="http://www.springframework.org/schema/util"
     xmlns:task="http://www.springframework.org/schema/task"
     xmlns:aop="http://www.springframework.org/schema/aop"
     xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.1.xsd
         http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-4.1.xsd
         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-4.1.xsd
         http://www.springframework.org/schema/lang http://www.springframework.org/schema/lang/spring-lang-4.1.xsd
         http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.1.xsd
         http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.1.xsd">
     <!-- 开启组件扫描 -->
     <context:component-scan base-package="com.xcz"></context:component-scan>
     <!-- 开启mvc标注 -->
     <mvc:annotation-driven></mvc:annotation-driven>
     <!-- 配置视图处理器 -->
     <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
         <property name="prefix" value="/WEB-INF/"></property>
         <property name="suffix" value=".jsp"></property>
     </bean>
 </beans>

mvc.xml

在web.xml配置

　　1.配置请求参数如入口

　　2.配置初始化参数

 <?xml version="1.0" encoding="UTF-8"?>
 <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" version="3.1">
   <display-name>SpringMVC-03</display-name>
   <welcome-file-list>
     <welcome-file>index.html</welcome-file>
     <welcome-file>index.htm</welcome-file>
     <welcome-file>index.jsp</welcome-file>
     <welcome-file>default.html</welcome-file>
     <welcome-file>default.htm</welcome-file>
     <welcome-file>default.jsp</welcome-file>
   </welcome-file-list>
   <!-- 配置请求入口 -->
   <servlet>
       <servlet-name>SpringMVC</servlet-name>
     <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
     <!-- 配置初始化参数 -->
         <init-param>
             <param-name>contextConfigLocation</param-name>
             <param-value>classpath:mvc.xml</param-value>
         </init-param>
         <load-on-startup>1</load-on-startup>
     </servlet>
   <servlet-mapping>
       <servlet-name>SpringMVC</servlet-name>
       <url-pattern>*.do</url-pattern>
   </servlet-mapping>
 </web-app>

web.xml

控制器获取页面请求参数方式如下：

　　1.使用HttpServletRequest获取直接定义 HttpServletRequest参数
　　2.直接把请求参数的名字定义成控制器的参数名
　　3.当页面参数和控制器参数不一致可以使用 @RequestParam("页面参数名")，加在控制器方法对应的参数上

 package com.xcz.controller;

 import javax.servlet.http.HttpServletRequest;

 import org.springframework.stereotype.Controller;
 import org.springframework.ui.Model;
 import org.springframework.ui.ModelMap;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.servlet.ModelAndView;

 @Controller
 public class LoginController {
     // 获取参数方式一
     @RequestMapping("/login.do")
     public String login(HttpServletRequest request) {
         String username = request.getParameter("username");
         String password = request.getParameter("password");
         System.out.println(username + ":" + password);
         return "login";
     }

     // 获取参数方式二
     @RequestMapping("/login2.do")
     public String login2(String username, String password) {
         System.out.println(username + ":" + password);
         return "login";
     }

     // 获取参数方式三
     @RequestMapping("/login3.do")
     public String login3(@RequestParam("username") String uname, @RequestParam("password") String pwd) {
         System.out.println(uname + ":" + pwd);
         return "login";
     }
 }

LoginController

 <%@ 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>Insert title here</title>
 </head>
 <body>
     <form action="${pageContext.request.contextPath }/login8.do">  <!--${pageContext.request.contextPath }动态获取路径  -->
         账号：<input type="text" name="username" ><br>
         密码：<input type="text" name="password" ><br>
         <input type="submit" value="登录"><br>
     </form>
 </body>
 </html>

login.lsp

控制器中数据传递给页面的方式如下：

　　1.使用 request session application 这些域对象传输
　　2.使用ModelAndView来传输数据
　　//mav.getModel().put("username", username);
　　mav.getModelMap().addAttribute("username", username);
　　3.使用 Model 来传输数据
　　4.使用ModelMap 进行传参

 package com.xcz.controller;

 import javax.servlet.http.HttpServletRequest;

 import org.springframework.stereotype.Controller;
 import org.springframework.ui.Model;
 import org.springframework.ui.ModelMap;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.servlet.ModelAndView;

 @Controller
 public class LoginController {
     // 將控制器中的数据传给页面方式一
     @RequestMapping("/login4.do")
     public String login4(@RequestParam("username") String uname, @RequestParam("password") String pwd,
             HttpServletRequest request) {
         System.out.println(uname + ":" + pwd);
         request.setAttribute("username", uname);
         return "main";
     }

     // 將控制器中的数据传给页面方式二
     @RequestMapping("/login5.do")
     public ModelAndView login5(@RequestParam("username") String uname, @RequestParam("password") String pwd) {
         System.out.println(uname + ":" + pwd);
         ModelAndView mav = new ModelAndView();
         mav.setViewName("main");
         mav.getModel().put("username", uname);
         return mav;
     }

     // 將控制器中的数据传给页面方式三
     @RequestMapping("/login6.do")
     public ModelAndView login6(@RequestParam("username") String uname, @RequestParam("password") String pwd,
             ModelAndView mav) {
         System.out.println(uname + ":" + pwd);
         mav.setViewName("main");
         mav.getModelMap().addAttribute("username", uname);
         // mav.getModelMap().put("username", uname);
         return mav;
     }

     // 將控制器中的数据传给页面方式四
     @RequestMapping("/login7.do")
     public String login7(@RequestParam("username") String uname, @RequestParam("password") String pwd, Model model) {
         System.out.println(uname + ":" + pwd);
         model.addAttribute("username", uname);
         return "main";
     }

     //將控制器中的数据传给页面方式五
     @RequestMapping("/login8.do")
     public String login8(@RequestParam("username") String uname, @RequestParam("password") String pwd,ModelMap map) {
         System.out.println(uname + ":" + pwd);
         map.put("username", uname);
         return "main";
     }
 }

LoginController

 <%@ 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>Insert title here</title>
 </head>
 <body>
     <form action="${pageContext.request.contextPath }/login8.do">  <!--${pageContext.request.contextPath }动态获取路径  -->
         账号：<input type="text" name="username" ><br>
         密码：<input type="text" name="password" ><br>
         <input type="submit" value="登录"><br>
     </form>
 </body>
 </html>

login.jsp

 <%@ 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>Insert title here</title>
 </head>
 <body>
     <h1>欢迎${username }来访</h1>
 </body>
 </html>

main.jsp

 实现重定向方式如下：

　　1.当控制器方法返回String时return"redirect:路径";
　　默认是转发,转发的结果直接交给ViewResolver可以通过加forward:来继续处理,而不交给ViewResolver

　　2.当控制器方法 返回 ModelAndView 时  使用RedirectView 完成重定向 （/代表项目名前面的部分 不包含项目名）

 package com.xcz.controller;

 import javax.servlet.http.HttpServletRequest;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.servlet.ModelAndView;
 import org.springframework.web.servlet.view.RedirectView;

 @Controller
 public class LoginController {
     private static final String URL = "toMain.do";
     @RequestMapping("/toLogin.do")
     public String toLogin() {
         return "login";
     }
     @RequestMapping("/toMain.do")
     public String toMain() {
         return "main";
     }
     // 实现重定向方式一
     @RequestMapping("/login.do")
     public String login(@RequestParam("username") String uname,@RequestParam("password") String pwd,HttpServletRequest request) {
         System.out.println(uname + ":" + pwd);
         request.setAttribute("usernameq", uname);
         request.setAttribute("password", pwd);
         //return "redirect:/toMain.do";  //使用redirect:  直接重定向，导致数据丢失，所以页面无法获取
         return "forward:/toMain.do";  //使用forward:  先转发后跳转到main.jsp，不会导致数据丢失，所以页面可以获取控制器数据
     }
     // 实现重定向方式二
     @RequestMapping("/login1.do")
     public ModelAndView login1(@RequestParam("username") String uname,@RequestParam("password") String pwd,HttpServletRequest request) {
         System.out.println(uname + ":" + pwd);  //打印后台数据
         String path = request.getServletContext().getContextPath();  //获取项目名前面的路径
         ModelAndView mView = new ModelAndView();
         RedirectView rView = new RedirectView(path + "/" + URL);  //将路径和项目名进行拼接起来
         mView.setView(rView);
         mView.getModelMap().addAttribute("username", uname);  //将控制器的数据传给页面
         return mView;
     }
 }

LoginController

 <%@ 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>Insert title here</title>
 </head>
 <body>
     <form action="${pageContext.request.contextPath }/login1.do">  <!--${pageContext.request.contextPath }动态获取路径  -->
         账号：<input type="text" name="username" ><br>
         密码：<input type="text" name="password" ><br>
         <input type="submit" value="登录"><br>
     </form>
 </body>
 </html>

login.jsp

 <%@ 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>Insert title here</title>
 </head>
 <body>
     <h1>欢迎${param.username }来访</h1>
 </body>
 </html>

main.jsp