1、创建项目 引入对应的依赖

<dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.2.2</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>

        <!-- lombok -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.10</version>
        </dependency>

2、配置数据库和Mapper映射 application.yml

server:
  port: 8088
spring:
  datasource:
    password: 12345678
    username: root
    url: jdbc:mysql://localhost:3306/zzrTest?characterEncoding=utf-8&useSSL=false&serverTimezone=UTC
    driver-class-name: com.mysql.cj.jdbc.Driver
  redis:
    port: 6379
    host: 127.0.0.1


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

在启动类上面加上MapperScan注解

@SpringBootApplication
@MapperScan("com.example.mybatis.demos.web.mapper")
public class MybatisApplication {

    public static void main(String[] args) {
        SpringApplication.run(MybatisApplication.class, args);
    }

}

3、写对应的Mapper接口 （注解方式）

package com.example.mybatis.demos.web.mapper;


import com.example.mybatis.demos.web.User;
import org.apache.ibatis.annotations.*;

import java.security.PrivateKey;
import java.util.List;

@Mapper
public interface UserMapper {

    String TABLE="user"; // 表名
    String SelectColum="id,name,age";

    String InsertColumn="name,age";

    @Insert("insert into "+TABLE+" ("+InsertColumn+" )" +"values (#{name},#{age} )")
    int insertUser(User user);


    @Results({@Result(property = "id",column = "id"),
            @Result(property = "name",column = "name"),
            @Result(property = "age",column = "age"),
            @Result(property = "createTime",column = "create_time"),
            @Result(property = "updateTime",column = "update_time"),
            })
    //@Lang(MybatisExtendedLanguageDriver.class)
    @Select("select "+SelectColum+" from "+TABLE)
    List<User> listUser();

    @Update("update "+TABLE +" set name=#{name} where id=#{id}")
    int updateUser(User user);

    /**
     * 更新指定的字段
     * */
    @Update("update user set  name=#{userName} where id=#{userId}")
     int updateUser2(@Param("userName")String userName,@Param("userId")Integer userId);
    @Update("update "+TABLE +" set "+
            " name=#{name},"+
            " age=#{age},"+
            " update_time=#{updateTime}" +
            " where id=#{id}")
    int updateUser3(User user) ;
}

xml方式

<?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="com.example.mybatis.demos.web.mapper.StudentMapper">
<resultMap id="BaseResultMap" type="com.example.mybatis.demos.web.model.Student">
    <id column="id" jdbcType="BIGINT" property="id"/>
    <result column="name" jdbcType="VARCHAR" property="name"/>
    <result column="age" jdbcType="BIGINT" property="age"/>
    <result column="create_time" jdbcType="TIMESTAMP" property="createTime"/>
    <result column="update_time" jdbcType="TIMESTAMP" property="updateTime"/>
    </resultMap>
    <!--基础查询字段 -->
<sql id="Base_Column_List">
    id, name, age, create_time, update_time
</sql>
<select id="getStudent"  resultMap="BaseResultMap">
    select
    <include refid="Base_Column_List"/>
    from student
    <!-- where id = #{id,jdbcType=BIGINT}-->
</select>

</mapper>