SpringMVC -- 获取参数的几种方法

秒速五厘米 2024-04-19 13:13 85阅读 0赞

## SpringMVC – 获取参数的几种方法 ##

**步骤一 搭建框架**

**POJO**

public class User {
    
        private String name; // 与请求参数名称相同
        private String upass;
        private String reupass;
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        public String getUpass() {
            return upass;
        }
    
        public void setUpass(String upass) {
            this.upass = upass;
        }
    
        public String getreupass() {
            return reupass;
        }
    
        public void setreupass(String age) {
            this.reupass = age;
        }

**DispatcherServlet 控制器**

<?xml version="1.0" encoding="UTF-8"?>
    <web-app version="2.4"
             xmlns="http://java.sun.com/xml/ns/j2ee"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
    	http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
    
    
    
    <display-name>springMVC</display-name>
    
    
        
        <servlet>
            <servlet-name>springmvc</servlet-name>
            <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    
    
            <init-param>
                <param-name>contextConfigLocation</param-name>
                <param-value>classpath:springmvc-servlet.xml</param-value>
            </init-param>
            
            <load-on-startup>1</load-on-startup>
        </servlet>
    
        <servlet-mapping>
            <servlet-name>springmvc</servlet-name>
            
            <url-pattern>/</url-pattern>
        </servlet-mapping>
    
    
    </web-app>

**springMVC配置文件**

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

**jsp**

**index 首页jsp**

**注册页面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>注册</title>
    </head>
    <body>
    <form action="${pageContext.request.contextPath }/user/register" method="post" name="registForm">
        <table border=1 bgcolor="lightblue" align="center">
            <tr>
                <td>姓名：</td>
                <td>
                    <input class="textSize" type="text" name="name" value="${name}" />
                </td>
            </tr>
            <tr>
                <td>密码：</td>
                <td>
                    <input class="textSize" type="password" maxlength="20" name="upass" />
                </td>
            </tr>
            <tr>
                <td>确认密码：</td>
                <td>
                    <input class="textSize" type="password" maxlength="20" name="reupass" />
                </td>
            </tr>
            <tr>
                <td colspan="2" align="center">
                    <input type="submit" value="注册"  />
                </td>
            </tr>
            </table>
    </form>
    </body>
    </html>

**登录页面jsp**

**成功页面jsp**

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
        <title>Title</title>
    </head>
    
    <body>
    <H1>登录成功</H1>
    </body>
    </html>

**转发Controller**

package com.springTest.Controller;
    
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    
    @Controller
    @RequestMapping("/index")
    public class IndexController {
        @RequestMapping("/login")
        public String login() {
            return "login"; // 跳转到/WEB-INF/jsp下的login.jsp
        }
    
        @RequestMapping("/register")
        public String register() {
            return "register";
        }
    }

**user请求处理Controller**

package com.springTest.Controller;
    
    import javax.servlet.http.HttpSession;
    
    import com.springTest.pojo.User;
    import org.apache.commons.logging.Log;
    import org.apache.commons.logging.LogFactory;
    import org.springframework.stereotype.Controller;
    import org.springframework.ui.Model;
    import org.springframework.web.bind.annotation.RequestMapping;
    
    
    @Controller
    @RequestMapping("/user")
    public class UserController {
        // 得到一个用来记录日志的对象，这样在打印信息的时候能够标记打印的是哪个类的信息
        private static final Log logger = LogFactory.getLog(UserController.class);
    
        /**
         * 处理登录 使用User对象(实体Bean) user接收注册页面提交的请求参数
         */
        @RequestMapping("/login")
        public String login(User user, HttpSession session, Model model) {
            if ("1".equals(user.getName()) && "1".equals(user.getUpass())) {
                session.setAttribute("u", user);
                logger.info("成功");
                return "main"; // 登录成功，跳转到 main.jsp
            } else {
                logger.info("失败");
                model.addAttribute("messageError", "用户名或密码错误");
                return "login";
            }
        }
    
        /**
         * 处理注册 使用User对象(实体Bean) user接收注册页面提交的请求参数
         */
        @RequestMapping("/register")
        public String register(User user, Model model) {
            if ("1".equals(user.getName())
                    && "1".equals(user.getUpass())) {
                logger.info("成功");
                return "login"; // 注册成功，跳转到 login.jsp
            } else {
                logger.info("失败");
                // 在register.jsp页面上可以使用EL表达式取出model的uname值
                model.addAttribute("uname", user.getName());
                return "register"; // 返回 register.jsp
            }
        }
    }

**总结**

基本简单的测试框架已经完成，复制粘贴应该可以跑起来了，框架如下

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDU1MDQ5MA_size_16_color_FFFFFF_t_70]  
步骤二开始测试

--------------------

## 对象绑定接收参数 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDU1MDQ5MA_size_16_color_FFFFFF_t_70 1]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDU1MDQ5MA_size_16_color_FFFFFF_t_70 2]  
![在这里插入图片描述][20190918175125699.png]

## 形参获取参数 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDU1MDQ5MA_size_16_color_FFFFFF_t_70 3]

## HttpServletRequest 接收请求获取参数 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDU1MDQ5MA_size_16_color_FFFFFF_t_70 4]

## 通过 @RequestParam 接收请求参数 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDU1MDQ5MA_size_16_color_FFFFFF_t_70 5]

RequestParam有两个参数  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDU1MDQ5MA_size_16_color_FFFFFF_t_70 6]

required必传项 如果设为true不传输会报错，否则为false ，如果为空默认为null如果是int类型不可使用会报错

value就是前段获取的值，后面可以自定义变量名称

常用的几种方法解说完毕

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[20190918175125699.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/18/d8530389bf0d40808a899d1f05e9132a.png
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