详解SpringMVC注解版前台向后台传值的两种方式

2019-11-26 12:37:23

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一、概述。

在很多企业的开法中常常用到SpringMVC+Spring+Hibernate（mybatis）这样的架构，SpringMVC相当于Struts是页面到Contorller直接的交互的框架也是界面把信息传输到Contorller层的一种架构，通过这个架构可以让我们把页面和Contorller层解耦，使得开发人员的分工更加明确。

二、代码演示。

1、首先配置SpringMVC环境。

1.1导入jar。

值得注意的是红色标记的commons-logging这个jar包一定得引入进去不然会报错。

1.2、xml配置文件。

web.xml

<?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" id="WebApp_ID" version="3.1"> <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>*.spring</url-pattern>   </servlet-mapping>   <welcome-file-list>     <welcome-file>index.jsp</welcome-file>   </welcome-file-list> </web-app>

springMVC-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.gaowei.controller" /> </beans>

2、前台界面代码。

<%@ 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="login.spring" method="post">   username:<input type="text" name="username">   <br/>   password:<input type="text" name="password">   <br/>   <input type="submit" value="登录"> </form> </body> </html>

No.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> No! </body> </html>

Ok.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>  OK！ welcome:${username} </body> </html>

3、Contorller层接收前台的两种方式。

方式一：

利用@RequestParam这个注解

package com.gaowei.controller;  import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestParam;  @Controller public class Login {    //方式一   @RequestMapping("/login")   public String login(@RequestParam("username") String username,             @RequestParam("password") String password,Model model){     if (username.equals(password))      {       model.addAttribute("username", username);       return "ok.jsp";     } else {       return "no.jsp";     }   } }

方式二：

package com.gaowei.controller;  import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestParam;  @Controller public class Login { @RequestMapping("/login")   public String login(String username,String password,Model model){     if (username.equals(password))      {       model.addAttribute("username", username);       return "ok.jsp";     } else {       return "no.jsp";     }   }  }

4、界面结果。

第一种传值方式：