1、新建maven项目，新建文件夹和配置文件如下

2、配置文件代码

generator.properties

driver=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=utf-8&autoReconnect=true&useSSL=false&serverTimezone=UTC
username=root
password=root
 
#entity 包名和 java目录
modelPackage=com.genox.model
modelProject=src/main/java
#sqlmap包名 和resources目录
sqlPackage=com.genox.mapper
sqlProject=src/main/java
#mapper包名和 java目录
mapperPackage=com.genox.dao
mapperProject=src/main/java

generatorConfig.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE generatorConfiguration PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
<generatorConfiguration>
    <!--导入属性配置 -->
    <properties resource="generator.properties"/>
    <!--pom有了之后可以不加-->
    <!--<classPathEntry
            location="C:\Users\admin\.m2\repository\mysql\mysql-connector-java\8.0.11\mysql-connector-java-8.0.11.jar" />-->
    <context id="context1">
        <!-- 注释 -->
        <commentGenerator>
            <property name="suppressAllComments" value="true" /><!-- 是否取消注释 -->
            <property name="suppressDate" value="true" /> <!-- 是否生成注释代时间戳 -->
        </commentGenerator>
 
        <jdbcConnection driverClass="${driver}"
                        connectionURL="${url}"
                        userId="${username}"
                        password="${password}" />
 
        <!-- 类型转换 -->
        <javaTypeResolver>
            <!-- 是否使用bigDecimal， false可自动转化以下类型（Long, Integer, Short, etc.） -->
            <property name="forceBigDecimals" value="false" />
        </javaTypeResolver>
 
        <javaModelGenerator targetPackage="${modelPackage}"
                            targetProject="${modelProject}" />
        <sqlMapGenerator targetPackage="${sqlPackage}" targetProject="${sqlProject}" />
        <javaClientGenerator targetPackage="${mapperPackage}"
                             targetProject="${mapperProject}" type="XMLMAPPER" />
 <!-- 去掉example生成   -->
        <table tableName="tb_user" schema="general"
               enableCountByExample="false" enableUpdateByExample="false" enableDeleteByExample="false"
               enableSelectByExample="false" selectByExampleQueryId="false"></table>

 <table tableName="tb_table2" schema="general"
               enableCountByExample="false" enableUpdateByExample="false" enableDeleteByExample="false"
               enableSelectByExample="false" selectByExampleQueryId="false"></table>
    </context>
</generatorConfiguration>

pom.xml增加插件

        <plugins>
            <plugin>
            <groupId>org.mybatis.generator</groupId>
            <artifactId>mybatis-generator-maven-plugin</artifactId>
            <version>1.3.2</version>
            <configuration>
                <configurationFile>
                    <!--这里是配置generatorConfig.xml的路径
                     不写默认在resources目录下找generatorConfig.xml文件
                     -->
                </configurationFile>
                <verbose>true</verbose>
                <overwrite>true</overwrite>
            </configuration>
            <dependencies>
                <dependency>
                    <groupId>mysql</groupId>
                    <artifactId>mysql-connector-java</artifactId>
                    <version>8.0.20</version>
                </dependency>
            </dependencies>
        </plugin>
       </plugins>

3、点击Edit configrations...（平常新建Tomcat的地方），点击+ 新建maven，填写如下

4、点击idea最右侧的maven project，选择Run configrations下的选项，点击运行即可自动生成代码