springMVC实现登录成功查询的功能

系统管理员 2023-10-10 20:48 15阅读 0赞

## 一、点击a标签跳转到登录页面 ##

代码如下：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <html>
      <head>
        <title>首页</title>
      </head>
      <body>
    <h2>欢迎来到项目首页</h2>
      <h3><a href="login.jsp">去登陆</a></h3>
      </body>
    </html>

运行效果如下：

![e6e8250cffae4f0d8e3ea2dc25f135a6.png][]

登录页面代码如下：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <html>
      <head>
          <title>登录</title>
      </head>
      <body>
        <form action="login" method="post">
          <table>
            账号：<input type="text" name="username"><br/>
            密码：<input type="password" name="password"><br/>
            <input type="submit" value="登录"/>
          </table>
        </form>
      </body>
    </html>

运行效果如下：

![9413028329684a9fade546fd3d2deeca.png][]

## 二、用户名的判断 ##

代码如下：

package com.dou.controller;
    
    import com.dou.bean.User;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.SessionAttributes;
    import org.springframework.web.servlet.ModelAndView;
    
    @Controller
    @SessionAttributes({"error","user"})//把msg数据的作用域变为session域
    public class UserController {
    
        //登录的处理程序
        @RequestMapping("/login")
        public ModelAndView login(User user){
            ModelAndView mv = new ModelAndView();
            if (user.getUsername().equals("admin")&&user.getPassword().equals("666")){
                mv.addObject("user",user);
                //登录成功，去请求查询商品信息
                mv.setViewName("redirect:/findAll");
            }else {
                //登录失败，跳转到错误页，发送错误提示
                mv.addObject("error","用户名或密码错误");
                mv.setViewName("error");
            }
            return mv;
        }
    }

## 三、做出响应，跳转页面 ##

#### 1、当账号密码正确进行全查操作 ####

代码如下：

package com.dou.controller;
    
    import com.dou.bean.Goods;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.SessionAttributes;
    import org.springframework.web.servlet.ModelAndView;
    
    import java.util.ArrayList;
    import java.util.List;
    
    @Controller
    @SessionAttributes({"goodsList"})
    public class GoodsController {
    
        //常规把数据以Java集合的方式放入session中传递给页面
        @RequestMapping("/findAll")
        public ModelAndView findAll(){
            ModelAndView modelAndView = new ModelAndView();
            //查询商品信息
            List<Goods> goodsList = new ArrayList<>();
            Goods g1 = new Goods();
            g1.setGid(1);
            g1.setGname("泡面");
            g1.setPrice(4.5);
    
            Goods g2 = new Goods();
            g2.setGid(2);
            g2.setGname("可乐");
            g2.setPrice(3.5);
    
    
            Goods g3 = new Goods();
            g3.setGid(3);
            g3.setGname("火腿肠");
            g3.setPrice(6.5);
    
            goodsList.add(g1);
            goodsList.add(g2);
            goodsList.add(g3);
    
            modelAndView.addObject("goodsList",goodsList);
            modelAndView.setViewName("redirect:zhuye.jsp");
            return modelAndView;
    
        }
    }

运行效果如下：

![4920ddfdfaab40649d0b2bc74f0b60dd.png][]

#### 2、当账号密码错误跳转错误页面 ####

代码如下：

<html>
    <head>
        <title>错误页</title>
    </head>
    <body>
    
    <h2>${error}</h2>
    
    </body>
    </html>

运行效果如下：

![ce0d3cabc9dc4b35b5a93c7fbe893939.png][]

[e6e8250cffae4f0d8e3ea2dc25f135a6.png]: https://img-blog.csdnimg.cn/e6e8250cffae4f0d8e3ea2dc25f135a6.png
[9413028329684a9fade546fd3d2deeca.png]: https://img-blog.csdnimg.cn/9413028329684a9fade546fd3d2deeca.png
[4920ddfdfaab40649d0b2bc74f0b60dd.png]: https://img-blog.csdnimg.cn/4920ddfdfaab40649d0b2bc74f0b60dd.png
[ce0d3cabc9dc4b35b5a93c7fbe893939.png]: https://img-blog.csdnimg.cn/ce0d3cabc9dc4b35b5a93c7fbe893939.png