3.2、UserMapper.java
package com.lu.youxiang.mapper;import com.lu.youxiang.pojo.User;import org.Apache.ibatis.annotations.Mapper;import org.springframework.stereotype.Repository;@Mapper@Repositorypublic interface UserMapper {/*** 注册，插入数据* @param user*/void insertUser(User user);/*** 根据邮箱查询* @param email* @return*/User queryByEmail(String email);} 
3.3、User.java
package com.lu.youxiang.pojo;public class User {private String username;private String password;private String email;//get和set方法省略了，自己生成一下} 
3.4、MailService.java ，重要 。
package com.lu.youxiang.service;import com.lu.youxiang.mapper.UserMapper;import com.lu.youxiang.pojo.User;import com.lu.youxiang.vo.UserVo;import com.lu.youxiang.vo.UserVoToUser;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.beans.factory.annotation.Value;import org.springframework.mail.SimpleMailMessage;import org.springframework.mail.javamail.JavaMailSender;import org.springframework.stereotype.Service;import javax.servlet.http.HttpSession;import java.util.Random;@Servicepublic class MailService {@Autowiredprivate JavaMailSender mailSender;//一定要用@Autowired@Autowiredprivate UserMapper userMapper;//注入UserMapper，交给bena//application.properties中已配置的值@Value("${spring.mail.username}")private String from;/*** 给前端输入的邮箱，发送验证码* @param email* @param session* @return*/public boolean sendMimeMail( String email, HttpSession session) {try {SimpleMailMessage mailMessage = new SimpleMailMessage();mailMessage.setSubject("验证码邮件");//主题//生成随机数String code = randomCode();//将随机数放置到session中session.setAttribute("email",email);session.setAttribute("code",code);mailMessage.setText("您收到的验证码是："+code);//内容mailMessage.setTo(email);//发给谁mailMessage.setFrom(from);//你自己的邮箱mailSender.send(mailMessage);//发送returntrue;}catch (Exception e){e.printStackTrace();return false;}}/*** 随机生成6位数的验证码* @return String code*/public String randomCode(){StringBuilder str = new StringBuilder();Random random = new Random();for (int i = 0; i < 6; i++) {str.append(random.nextInt(10));}return str.toString();}/*** 检验验证码是否一致* @param userVo* @param session* @return*/public boolean registered(UserVo userVo, HttpSession session){//获取session中的验证信息String email = (String) session.getAttribute("email");String code = (String) session.getAttribute("code");//获取表单中的提交的验证信息String voCode = userVo.getCode();//如果email数据为空，或者不一致，注册失败if (email == null || email.isEmpty()){//return "error,请重新注册";return false;}else if (!code.equals(voCode)){//return "error,请重新注册";return false;}//保存数据User user = UserVoToUser.toUser(userVo);//将数据写入数据库userMapper.insertUser(user);//跳转成功页面return true;}/*** 通过输入email查询password，然后比较两个password，如果一样，登录成功* @param email* @param password* @return*/public boolean loginIn(String email, String password){User user = userMapper.queryByEmail(email);if(!user.getPassword().equals(password)){return false;}System.out.println("登录成功:数据库密码是："+user.getPassword());return true;}} 
3.5、UserVo.java
package com.lu.youxiang.vo;public class UserVo {private String username;private String password;private String email;//验证码private String code;//省略了get和set方法，自己生成一下 } 
3.6、UserVoToUser.java
package com.lu.youxiang.vo;import com.lu.youxiang.pojo.User;public class UserVoToUser {/*** 将表单中的对象转化为数据库中存储的用户对象（剔除表单中的code）* @param userVo* @return*/public static User toUser(UserVo userVo) {//创建一个数据库中存储的对象User user = new User();//传值user.setUsername(userVo.getUsername());user.setPassword(userVo.getPassword());user.setEmail(userVo.getEmail());// 返回包装后的对象return user;}}主配置类不复制了，创建springboot项目后，就有 。
3.7、UserMapper.xml
在resources包下创建mapper包，用来放xml，然后再这个包中创建UserMapper.xml，内容如下 。
<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="com.lu.youxiang.mapper.UserMapper"><insert id="insertUser" parameterType="com.lu.youxiang.pojo.User">insert into user (username,password,email)values (#{username},#{password},#{email})</insert><select id="queryByEmail" resultType="com.lu.youxiang.pojo.User">select *from userwhere email = #{email}</select></mapper>