mybatis-plus官方文档：https://mp.baomidou.com/guide/
新建一个Springboot项目 ；代码生成结构如下
一。添加依赖

<dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.0.0</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>

        <dependency>
            <groupId>net.sourceforge.nekohtml</groupId>
            <artifactId>nekohtml</artifactId>
            <version>1.9.22</version>
        </dependency>
        <!-- 导入mysql驱动包-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.11</version>
        </dependency>
        <!-- 导入数据源依赖-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.9</version>
        </dependency>
         <!--利用fastJson替换掉jackson，且解决中文乱码问题-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.54</version>
        </dependency>
        <!-- 分页插件 -->
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper-spring-boot-starter</artifactId>
            <version>1.2.3</version>
        </dependency>
        <!-- lombok -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

        <!--mybatisplus插件-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.1.1</version>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus</artifactId>
            <version>3.1.1</version>
        </dependency>
        <!--生成策略-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-generator</artifactId>
            <version>3.1.1</version>
        </dependency>
        <!-- 这是模板引擎依赖 -->
        <dependency>
            <groupId>org.freemarker</groupId>
            <artifactId>freemarker</artifactId>
            <version>2.3.28</version>
        </dependency>
        <dependency>
            <groupId>org.apache.velocity</groupId>
            <artifactId>velocity-engine-core</artifactId>
            <version>2.0</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

二。application.yml配置文件

server:
  port: 9017
spring:
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=UTF-8&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=GMT%2B8
    username: root
    password: root
    driver-class-name: com.mysql.jdbc.Driver
    druid:
      initialSize: 1
      minIdle: 1
      maxActive: 10
      maxWait: 10000
      timeBetweenEvictionRunsMillis: 60000
      minEvictableIdleTimeMillis: 300000
      validationQuery: select 1
      testWhileIdle: true
      testOnBorrow: true
      testOnReturn: false
      poolPreparedStatements: true
      maxPoolPreparedStatementPerConnectionSize: 20
      filters: stat
  profiles:
        include: jdbc

mybatis-plus:
  # 如果是放在src/main/java目录下 classpath:/com/yourpackage/*/mapper/*Mapper.xml
  # 如果是放在resource目录 classpath:/mapper/*Mapper.xml
  mapper-locations: classpath:mapper/*Mapper.xml
  #实体扫描，多个package用逗号或者分号分隔
  typeAliasesPackage: com.demo.updown.entity
  global-config:
    db-config:
      column-underline: false
      logic-delete-value: 1
      logic-not-delete-value: 0
    refresh: true
    configuration:
      map-underscore-to-camel-case: true
      cache-enabled: false
      jdbc-type-for-null: 'null'
      log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
      database-id: mysql
    configuration-properties:
      blobType: BLOB
      boolValue: TRUE
      prefix:

到这基本配置完成，下面是代码生成器

package com.demo.updown.until;



import com.baomidou.mybatisplus.core.toolkit.StringPool;
import com.baomidou.mybatisplus.generator.AutoGenerator;
import com.baomidou.mybatisplus.generator.InjectionConfig;
import com.baomidou.mybatisplus.generator.config.*;
import com.baomidou.mybatisplus.generator.config.po.TableFill;
import com.baomidou.mybatisplus.generator.config.po.TableInfo;
import com.baomidou.mybatisplus.generator.config.rules.NamingStrategy;
import com.baomidou.mybatisplus.generator.engine.FreemarkerTemplateEngine;

import java.util.ArrayList;
import java.util.List;

public class MysqlGenertor {

    public static void main(String[] args) {
        // 代码生成器
        AutoGenerator mpg = new AutoGenerator();

        // 全局配置
        GlobalConfig gc = new GlobalConfig();
        String projectPath = System.getProperty("user.dir");
        gc.setOutputDir(projectPath + "/src/main/java");
        // TODO 设置用户名
        gc.setAuthor("root");
        gc.setOpen(true);
        // service 命名方式
        gc.setServiceName("%sService");
        // service impl 命名方式
        gc.setServiceImplName("%sServiceImpl");
        // 自定义文件命名，注意 %s 会自动填充表实体属性！
        gc.setMapperName("%sDao");
        gc.setXmlName("%sMapper");
        gc.setFileOverride(true);
        gc.setActiveRecord(true);
        // XML 二级缓存
        gc.setEnableCache(false);
        // XML ResultMap
        gc.setBaseResultMap(true);
        // XML columList
        gc.setBaseColumnList(false);
        mpg.setGlobalConfig(gc);

        // TODO 数据源配置
        DataSourceConfig dsc = new DataSourceConfig();

        dsc.setUrl("jdbc:mysql://localhost:3306/test?useUnicode=true&useSSL=false&characterEncoding=utf8&serverTimezone=GMT%2B8");
        dsc.setDriverName("com.mysql.jdbc.Driver");
        dsc.setUsername("root");
        dsc.setPassword("root");
        mpg.setDataSource(dsc);

        // TODO 包配置
        PackageConfig pc = new PackageConfig();
        //pc.setModuleName(scanner("模块名"));
        pc.setParent("com.demo.updown");//项目的包名
        pc.setEntity("entity");// 实体类
        pc.setService("service");//接口包
        pc.setMapper("mapper");//dao层
        pc.setServiceImpl("serviceImpl");//实现类
        mpg.setPackageInfo(pc);

        // 自定义需要填充的字段
        List<TableFill> tableFillList = new ArrayList<>();
        //如 每张表都有一个创建时间、修改时间
        //而且这基本上就是通用的了，新增时，创建时间和修改时间同时修改
        //修改时，修改时间会修改，
        //虽然像Mysql数据库有自动更新几只，但像ORACLE的数据库就没有了，
        //使用公共字段填充功能，就可以实现，自动按场景更新了。
        //如下是配置
        //TableFill createField = new TableFill("gmt_create", FieldFill.INSERT);
        //TableFill modifiedField = new TableFill("gmt_modified", FieldFill.INSERT_UPDATE);
        //tableFillList.add(createField);
        //tableFillList.add(modifiedField);

        // 自定义配置
        InjectionConfig cfg = new InjectionConfig() {
            @Override
            public void initMap() {
                // to do nothing
            }
        };
        List<FileOutConfig> focList = new ArrayList<>();
        focList.add(new FileOutConfig("/templates/mapper.xml.ftl") {
            @Override
            public String outputFile(TableInfo tableInfo) {
                // 自定义输入文件名称 这里设置生成的mapper.xml文件的存放位置
                return projectPath + "/src/main/resources/mapper/"
                        + "/" + tableInfo.getEntityName() + "Mapper" + StringPool.DOT_XML;
            }
        });
        cfg.setFileOutConfigList(focList);
        mpg.setCfg(cfg);
        mpg.setTemplate(new TemplateConfig().setXml(null));

        // 策略配置
        StrategyConfig strategy = new StrategyConfig();
        strategy.setNaming(NamingStrategy.underline_to_camel);
        strategy.setColumnNaming(NamingStrategy.underline_to_camel);
        strategy.setEntityLombokModel(true);
        // 设置逻辑删除键
        strategy.setLogicDeleteFieldName("deleted");
        // TODO 指定生成的bean的数据库表名
        strategy.setInclude("student");
        //strategy.setSuperEntityColumns("id");
        // 驼峰转连字符
        strategy.setControllerMappingHyphenStyle(true);
        mpg.setStrategy(strategy);
        // 选择 freemarker 引擎需要指定如下加，注意 pom 依赖必须有！
        mpg.setTemplateEngine(new FreemarkerTemplateEngine());
        mpg.execute();
    }

}

```运行代码即可