javaweb--简单的login用户登录

左手的ㄟ右手 2022-09-10 11:23 175阅读 0赞

简单jsp前后台交互实现登录 无数据库校验！

## login.jsp ##

<%--
      Created by IntelliJ IDEA.
      User: Administrator
      Date: 2021/9/7 0007
      Time: 16:49
      To change this template use File | Settings | File Templates.
    --%>
    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <html>
    <head>
        <title>登录</title>
    </head>
    <body>
    <form method="post" action="loginServlet">
        姓名: <input name="uname" type="txt"> <br>
        密码: <input name="upwd" type="password"><br>
        <button>提交</button>
        <%--获取后台设置在作用域中的数据并显示--%>
        <span style="color: red;font-size: 12px"><%=request.getAttribute("msg")%></span>
    </form>
    
    
    </body>
    </html>

## loginServlet.class ##

package com.liu.controller;
    
    import sun.util.resources.cldr.ml.CalendarData_ml_IN;
    
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    
    @WebServlet("/loginServlet")
    public class loginServlet extends HttpServlet {
        
        @Override
        protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        
          //设置客户端编码
            request.setCharacterEncoding("UTF-8");
    
            //接受客户端传递的参数
    
            String uname = request.getParameter("uname");
            String upwd = request.getParameter("upwd");
            //判断参数是否为空
            if(uname == null || "".equals(uname.trim())){
        
                //提示用户信息
                request.setAttribute("msg","用户姓名不能为空！");
                //跳转回登录请求转发
                request.getRequestDispatcher("login.jsp").forward(request,response);
                return;
            }
    
            if(upwd == null || "".equals(upwd.trim())){
        
                //提示用户信息
                request.setAttribute("msg","用户密码不能为空！");
                //跳转回登录请求转发
                request.getRequestDispatcher("login.jsp").forward(request,response);
                return;
            }
            //判断账号密码是否正确 uname = admin ；admin = admin
            if (!"admin".equals(uname)||!"admin".equals(upwd)){
        
                request.setAttribute("msg","登录失败！");
                request.getRequestDispatcher("login.jsp").forward(request,response);
                return;
            }
            //登录成功
            //设置登录信息到session作用域
            request.getSession().setAttribute("uname",uname);
            //跳转到首页
           response.sendRedirect("index.jsp");
        }
    }

## index.jsp ##

<%--
      Created by IntelliJ IDEA.
      User: Administrator
      Date: 2021/9/7 0007
      Time: 16:14
      To change this template use File | Settings | File Templates.
    --%>
    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <html>
      <head>
        <title>登录</title>
      </head>
      <body>
      <h2>欢迎<%=session.getAttribute("uname")%>登录！</h2>
      </body>
    </html>

## 姓名为空 ##

![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5YiY5ZCR6Ziz5ZWK_size_20_color_FFFFFF_t_70_g_se_x_16]

## 密码为空 ##

![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5YiY5ZCR6Ziz5ZWK_size_20_color_FFFFFF_t_70_g_se_x_16 1]

## 账号密码错误！ ##

![在这里插入图片描述][ed94623994324b46847fd2fb771e2563.png]

## 登录成功 ##

![在这里插入图片描述][watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5YiY5ZCR6Ziz5ZWK_size_20_color_FFFFFF_t_70_g_se_x_16 2]

[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5YiY5ZCR6Ziz5ZWK_size_20_color_FFFFFF_t_70_g_se_x_16]: /images/20220829/bd6eb65681af4155b270f2af65ac6167.png
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5YiY5ZCR6Ziz5ZWK_size_20_color_FFFFFF_t_70_g_se_x_16 1]: /images/20220829/67867a99c79042a7aa6563c62426d147.png
[ed94623994324b46847fd2fb771e2563.png]: /images/20220829/dc5755157e47426d9abba204bbc707a5.png
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5YiY5ZCR6Ziz5ZWK_size_20_color_FFFFFF_t_70_g_se_x_16 2]: /images/20220829/5105a0701b7e471cb2cdcd9bd3ff8537.png