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10-案例-用户注册(获取自增id)

发布时间：2024-12-07 13:49:46编辑：雪饮阅读（）

其实这次主要想要实现的同样是对前番实现的注册功能的整合，整合到上篇中的项目中。
那么其实第一个就是我觉得把注册与登录都整合在一个service中，并需要考虑封装下注册成功后记住密码功能肯定要清理下，不然跳转到登录界面的时候还记录之前的用户名和密码，真就不太好了,另外也统一处理下中文乱码，所以也用之前的工具类来获取参数。所以这个service则如：
package com.service;

import com.mapper.UserMapper;
import com.pojo.User;
import com.util.SessionFactoryUtil;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;

import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;
import java.net.URLEncoder;

public class UserService {
    SqlSessionFactory sqlSessionFactory= SessionFactoryUtil.getSqlSessionFactory();
    public void cleanRemember(HttpServletRequest req,HttpServletResponse resp,User user){
        String remember=req.getParameter("remember");
        Cookie cookie_u=new Cookie("username", URLEncoder.encode(user.getUsername()));
        Cookie cookie_c=new Cookie("password", user.getPassword());
        Cookie remember_c=new Cookie("remember", remember);
        cookie_u.setMaxAge(0);
        cookie_c.setMaxAge(0);
        remember_c.setMaxAge(0);
        resp.addCookie(cookie_u);
        resp.addCookie(cookie_c);
        resp.addCookie(remember_c);
    }
    public User login(HttpServletRequest req,HttpServletResponse resp) throws IOException {
        SqlSession sqlSession=sqlSessionFactory.openSession();
        UserMapper userMapper=sqlSession.getMapper(UserMapper.class);


        String username=SessionFactoryUtil.getParameter(req,"username");
        String password=SessionFactoryUtil.getParameter(req,"password");



        User user=userMapper.select(username,password);
        sqlSession.close();
        if(user!=null){
            HttpSession session= req.getSession();
            session.setAttribute("user",user);
            String remember=req.getParameter("remember");
            if(remember==null){
                remember="";
            }

            Cookie cookie_u=new Cookie("username", URLEncoder.encode(user.getUsername()));
            Cookie cookie_c=new Cookie("password", user.getPassword());
            Cookie remember_c=new Cookie("remember", remember);
            if(remember.equals("1")){
                cookie_u.setMaxAge(60*60*24*7);
                cookie_c.setMaxAge(60*60*24*7);
                remember_c.setMaxAge(60*60*24*7);
                resp.addCookie(cookie_u);
                resp.addCookie(cookie_c);
                resp.addCookie(remember_c);
            }
            if(remember.equals("1")==false){
                cookie_u.setMaxAge(0);
                cookie_c.setMaxAge(0);
                remember_c.setMaxAge(0);
                cleanRemember(req,resp,user);
            }

        }



        return user;
    }
    public User register(HttpServletRequest req,HttpServletResponse resp){

        User user=new User();
        String username=SessionFactoryUtil.getParameter(req,"username");
        String password=SessionFactoryUtil.getParameter(req,"password");

        user.setUsername(username);
        user.setPassword(password);

        SqlSession sqlSession=sqlSessionFactory.openSession(true);
        UserMapper userMapper=sqlSession.getMapper(UserMapper.class);

        if(userMapper.selectByUsername(username)==null){
            userMapper.add(user);
            sqlSession.close();

            cleanRemember(req,resp,user);
            return user;
        }
        sqlSession.close();
        return null;
    }
}
 
那么登录的servlet的逻辑则也对应稍加调整
package com.web;
import com.pojo.User;
import com.service.UserService;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.*;
import java.io.IOException;

@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {
    UserService userService=new UserService();
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        User user=userService.login(req,resp);
        resp.setContentType("text/html;charset=utf-8");
        if(user==null){
            req.setAttribute("msg","用户名或密码错误");
            req.getRequestDispatcher("/login.jsp").forward(req,resp);
        }
        else{
            resp.sendRedirect(req.getContextPath()+"/ServletQueryAll");
        }
    }
}
那么注册的servlet则可以更加简化了
package com.web;
import com.pojo.User;
import com.service.UserService;
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("/registerServlet")
public class RegisterServlet extends HttpServlet {
    UserService userService=new UserService();
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        User newUser=userService.register(req,resp);
        if(newUser!=null){
            req.setAttribute("register_msg","注册成功，请登录");
            req.getRequestDispatcher("/login.jsp").forward(req,resp);
        }
        if(newUser==null){
            req.setAttribute("register_error","用户名已存在");
            req.getRequestDispatcher("/register.jsp").forward(req,resp);
        }

    }
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req,resp);
    }
}
注册页面register.jsp同样也需要能响应注册失败的信息，所以register.jsp则修改如：
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>欢迎注册</title>
    <link href="css/register.css" rel="stylesheet">
    <style>
        .msg{
            color:red;
        }
    </style>
</head>
<body>

<div class="form-div">
    <div class="reg-content">
        <h1>欢迎注册</h1>
        <span>已有帐号？</span> <a href="login.jsp">登录</a>
    </div>
    <form id="reg-form" action="${pageContext.request.contextPath}/registerServlet" method="post">

        <table>

            <tr>
                <td>用户名</td>
                <td class="inputs">
                    <input name="username" type="text" id="username">
                    <br>
                    <span id="username_err" class="err_msg">${register_error}</span>
                </td>

            </tr>

            <tr>
                <td>密码</td>
                <td class="inputs">
                    <input name="password" type="password" id="password">
                    <br>
                    <span id="password_err" class="err_msg" style="display: none">密码格式有误</span>
                </td>
            </tr>


        </table>

        <div class="buttons">
            <input value="注 册" type="submit" id="reg_btn">
        </div>
        <br class="clear">
    </form>

</div>
</body>
</html>
登录的jsp页面login.jsp同样需要响应从注册成功转发过来的注册成功消息，以及登录页面也是需要处理cookie不能存储中文的情况，所以需要对中文的url编码后cookie的反解，当然也有一种就是直接存储json对象或许更好，这里暂不纠结了，所以login.jsp修改如：
<%@ page import="java.net.URLEncoder" %>
<%@ page import="java.net.URLDecoder" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<html lang="en">
<%
    String decodeUserName="";
    for(Cookie cookieItem:request.getCookies()){
        String cookieValue=cookieItem.getValue();
        String cookieName=cookieItem.getName();
        if(cookieName.equals("username")){
            decodeUserName= URLDecoder.decode(cookieValue);
        }
    }
%>
<head>
    <meta charset="UTF-8">
    <title>login</title>
    <link href="css/login.css" rel="stylesheet">
    <style>
        .msg{
            color:red;
        }
    </style>
</head>

<body>
<div id="loginDiv">
    <form action="${pageContext.request.contextPath}/loginServlet" id="form">
        <h1 id="loginMsg">LOGIN IN</h1>
        <div class="msg">${msg}</div>
        <div class="msg">${register_msg}</div>
        <p>Username:<input id="username" name="username" type="text" value="${decodeUserName}"></p>

        <p>Password:<input id="password" name="password" type="password" value="${cookie.password.value}"></p>
        <p>remember:<input type="checkbox" name="remember" value="1" <c:if test="${cookie.remember.value == 1}"> checked </c:if> /></p>
        <div id="subDiv">
            <input type="submit" class="button" value="login up">
            <input type="reset" class="button" value="reset">&nbsp;&nbsp;&nbsp;
            <a href="register.jsp">没有账号？点击注册</a>
        </div>
    </form>
</div>

</body>
</html>
 
但对于注册所用的userMapper接口中的add方法，则这里不用传统的insert了，因为这里我的偏好做法是能获取到增长id，所以这里则修改如：
package com.mapper;
import com.pojo.User;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;

public interface UserMapper {
    User select(@Param("username") String username, @Param("password") String password);

    @Select("select * from tb_user where username=#{username}")
    User selectByUsername(String username);
    void add(User user);
}
那么同样的userMapper的配置文件中要声明增长id回调赋值及回调赋值于pojo的属性名
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "https://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.mapper.UserMapper">
    <select id="select" resultType="User">
        select * from tb_user where username=#{username} and password=#{password};
    </select>
    <insert id="add" useGeneratedKeys="true" keyProperty="id">
        insert into tb_user(`username`,`password`) value(#{username},#{password})
    </insert>
</mapper>
useGeneratedKeys开启了回调赋值，keyProperty决定了回调赋值于pojo的属性名。
则add方法接收的user对象，在add处理完成后该user对象的id值就会被赋值为自增id的值。
登录成功后进入品牌列表，品牌列表顶部需要显示当前登录用户名，所以brand.jsp也修改后如：
<%--
  Created by IntelliJ IDEA.
  User: 1
  Date: 2024/12/2
  Time: 15:15
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<p>欢迎你,${pageContext.request.getSession().getAttribute("user").username}</p>
<a href="addBrand.jsp">添加品牌</a>
<table border="1" cellspacing="0" width="800">
    <tr>
        <th>序号</th>
        <th>索引</th>
        <th>ID</th>
        <th>品牌名称</th>
        <th>企业名称</th>
        <th>排序</th>
        <th>品牌介绍</th>
        <th>状态</th>
        <th>操作</th>

    </tr>
    <c:forEach items="${brands}" var="brand" varStatus="status">
        <tr>
            <th>${status.count}</th>
            <th>${status.index}</th>
            <th>${brand.id}</th>
            <th>${brand.brandName}</th>
            <th>${brand.companyName}</th>
            <th>${brand.ordered}</th>
            <th>${brand.description}</th>
            <th>
                <c:if test="${brand.status == 1}">
                    启用
                </c:if>
                <c:if test="${brand.status == 0}">
                    禁用
                </c:if>
            </th>
            <th>
                <a href="/threeTierArchitectureModule/BrandUpdateById?id=${brand.id}">修改</a>
            </th>
        </tr>
    </c:forEach>
</table>
</body>
</html>