<dependency>

             <groupId>org.mybatis.spring.boot</groupId>

             <artifactId>mybatis-spring-boot-starter</artifactId>

             <version>2.0.0</version>

         </dependency>

 package cn.coreqi.mapper;

 import cn.coreqi.entities.User;

 import org.apache.ibatis.annotations.Mapper;

 @Mapper

 public interface UserMapper {

     public User getUserById(Integer id);

     public int addUser(User user);

     public int modifyUser(User user);

     public int delUserById(Integer id);

 }

 <?xml version="1.0" encoding="UTF-8" ?>

 <!DOCTYPE configuration

         PUBLIC "-//mybatis.org//DTD Config 3.0//EN"

         "http://mybatis.org/dtd/mybatis-3-config.dtd">

 <configuration>

     <settings>

         <setting name="mapUnderscoreToCamelCase" value="True"/>

     </settings>

 </configuration>

 <?xml version="1.0" encoding="UTF-8" ?>

 <!DOCTYPE mapper

         PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"

         "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

 <mapper namespace="cn.coreqi.mapper.UserMapper">

     <select id="getUserById" resultType="cn.coreqi.entities.User">

         select * from users where Id = #{id}

     </select>

     <insert id="addUser" useGeneratedKeys="true" keyProperty="Id">

         insert into users(UserName,PassWord,Enabled) values(#{UserName},#{PassWord},#{Enabled})

     </insert>

     <update id="modifyUser">

         update users set UserName = #{UserName},PassWord = #{PassWord},Enabled = #{Enabled} where Id = #{Id}

     </update>

     <delete id="delUserById">

         delete from users where Id = #{id}

     </delete>

 </mapper>

 spring.datasource.username=root

 spring.datasource.password=123456

 spring.datasource.url=jdbc:mysql://localhost:3306/JdbcDemo?serverTimezone=UTC

 spring.datasource.driver-class-name=com.mysql.jdbc.Driver

 spring.datasource.type=com.alibaba.druid.pool.DruidDataSource

 mybatis.config-location=classpath:mybatis/mybatis-config.xml

 mybatis.mapper-locations=classpath:mybatis/mapper/*.xml