pom依赖

<dependency>
    <groupId>org.mybatis.generator</groupId>
    <artifactId>mybatis-generator-core</artifactId>
    <version>1.3.7</version>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.15</version>
</dependency>
<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis</artifactId>
    <version>3.4.0</version>
</dependency>

自定义 GeneratorMain

package com.ikeeper.mybatis;

import org.mybatis.generator.api.IntrospectedColumn;
import org.mybatis.generator.api.IntrospectedTable;
import org.mybatis.generator.api.MyBatisGenerator;
import org.mybatis.generator.api.dom.java.Field;
import org.mybatis.generator.api.dom.java.TopLevelClass;
import org.mybatis.generator.config.Configuration;
import org.mybatis.generator.config.xml.ConfigurationParser;
import org.mybatis.generator.internal.DefaultCommentGenerator;
import org.mybatis.generator.internal.DefaultShellCallback;
import org.mybatis.generator.internal.util.StringUtility;

import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;

public class GeneratorMain extends DefaultCommentGenerator {
    private boolean addRemarkComments = false;

    public static void main(String[] args) throws Exception {

        System.setProperty("jdbc.url", "jdbc:mysql://localhost:3306/electronic_ledger?serverTimezone=UTC");
        System.setProperty("jdbc.username", "root");
        System.setProperty("jdbc.password", "root");

        System.setProperty("entity.target.package", "com.ikeeper.entity.base");//实体类目录
        System.setProperty("mapper.xml.target.package", "mybatis-mapper.base");//mapper.xml 目录
        System.setProperty("mapper.class.target.package", "com.ikeeper.mapper.base");//mapper.class 目录


        System.setProperty("table.name", "ledger_task");//表名

        //MBG 执行过程中的警告信息
        List<String> warnings = new ArrayList<String>();
        //当生成的代码重复时,覆盖原代码
        boolean overwrite = true;
        //读取我们的 MBG 配置文件
        InputStream is = GeneratorMain.class.getResourceAsStream("/mybatis-generator.xml");
        ConfigurationParser cp = new ConfigurationParser(warnings);
        Configuration config = cp.parseConfiguration(is);
        is.close();

        DefaultShellCallback callback = new DefaultShellCallback(overwrite);
        //创建 MBG
        MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config, callback, warnings);
        //执行生成代码
        myBatisGenerator.generate(null);
        //输出警告信息
        for (String warning : warnings) {
            System.out.println(warning);
        }
    }

    /**
     * 设置用户配置的参数
     */
    @Override
    public void addConfigurationProperties(Properties properties) {
        super.addConfigurationProperties(properties);
        addRemarkComments = StringUtility.isTrue(properties.getProperty("addRemarkComments"));
    }

    /**
     * 给字段添加注释
     */
    @Override
    public void addFieldComment(Field field, IntrospectedTable introspectedTable,
                                IntrospectedColumn introspectedColumn) {
        if (!addRemarkComments) {
            return;
        }
        String remarks = introspectedColumn.getRemarks();
        //根据参数和备注信息判断是否添加备注信息
        if (StringUtility.stringHasValue(remarks)) {
            //数据库中特殊字符需要转义
            if (remarks.contains("\"")) {
                remarks = remarks.replace("\"", "'");
            }
            addFieldJavaDoc(field, remarks);

        }
    }

    /**
     * 给model的字段添加注释
     */
    private void addFieldJavaDoc(Field field, String remarks) {
        field.addJavaDocLine("/**");
        field.addJavaDocLine("* " + remarks);
        field.addJavaDocLine("*/");
    }


    /**
     * 实体类添加的注释
     *
     * @param topLevelClass
     * @param introspectedTable
     */
    @Override
    public void addModelClassComment(TopLevelClass topLevelClass,
                                     IntrospectedTable introspectedTable) {
        if (!addRemarkComments) {
            return;
        }

        topLevelClass.addJavaDocLine("/**"); //$NON-NLS-1$
        String remarks = introspectedTable.getRemarks();
        if (StringUtility.stringHasValue(remarks)) {
            topLevelClass.addJavaDocLine(" * " + remarks);
        }
        topLevelClass.addJavaDocLine(" * " + introspectedTable.getFullyQualifiedTable().toString());
        topLevelClass.addJavaDocLine(" */");
    }


}

配置:mybatis-generator.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>
    <context id="MysqlContext" targetRuntime="MyBatis3">
        <property name="beginningDelimiter" value="`"/>
        <property name="endingDelimiter" value="`"/>
        <property name="javaFileEncoding" value="UTF-8"/>
        <!-- 为模型生成序列化方法-->
        <plugin type="org.mybatis.generator.plugins.SerializablePlugin"/>
        <!-- 为生成的Java模型创建一个toString方法 -->
        <plugin type="org.mybatis.generator.plugins.ToStringPlugin"/>
        <!--生成mapper.xml时覆盖原文件-->
        <plugin type="org.mybatis.generator.plugins.UnmergeableXmlMappersPlugin"/>
        <plugin type="org.mybatis.generator.plugins.MapperAnnotationPlugin"/>


        <commentGenerator type="com.ikeeper.mybatis.GeneratorMain">
            <!-- 是否生成注释代时间戳-->
            <property name="suppressDate" value="true"/>
            <!-- 是否去除自动生成的注释 true:是 : false:否 -->
            <property name="suppressAllComments" value="true"/>

            <property name="addRemarkComments" value="true"/>
        </commentGenerator>
        <!--数据库链接地址账号密码-->
        <jdbcConnection driverClass="com.mysql.cj.jdbc.Driver"
                        connectionURL="${jdbc.url}"
                        userId="${jdbc.username}"
                        password="${jdbc.password}">
        </jdbcConnection>
        <javaTypeResolver>
            <!--该属性可以控制是否强制DECIMAL和NUMERIC类型的字段转换为Java类型的java.math.BigDecimal,默认值为false,一般不需要配置。-->
            <property name="forceBigDecimals" value="false"/>
        </javaTypeResolver>
        <!--生成Model类存放位置-->
        <javaModelGenerator targetPackage="${entity.target.package}" targetProject="src/main/java">
            <!--enableSubPackages:如果true,MBG会根据catalog和schema来生成子包。如果false就会直接用targetPackage属性。默认为false。-->
            <property name="enableSubPackages" value="true"/>
            <!--trimStrings:是否对数据库查询结果进行trim操作,如果设置为true就会生成类似这样public void setUsername(String username) {this.username = username == null ? null : username.trim();}的setter方法。默认值为false。-->
            <!--            <property name="trimStrings" value="true"/>-->
        </javaModelGenerator>
        <!--生成映射xml文件存放位置-->
        <sqlMapGenerator targetPackage="${mapper.xml.target.package}" targetProject="src/main/resources/">
            <property name="enableSubPackages" value="true"/>
        </sqlMapGenerator>
        <!--生成Dao类存放位置(*Mapper.java)-->
        <!-- 客户端代码,生成易于使用的针对Model对象和XML配置文件 的代码
            type="ANNOTATEDMAPPER",生成Java Model 和基于注解的Mapper对象
            type="MIXEDMAPPER",生成基于注解的Java Model 和相应的Mapper对象
            type="XMLMAPPER",生成SQLMap XML文件和独立的Mapper接口
        -->
        <javaClientGenerator type="XMLMAPPER" targetPackage="${mapper.class.target.package}"
                             targetProject="src/main/java">
            <property name="enableSubPackages" value="true"/>
        </javaClientGenerator>
        <!--生成对应表及类名-->
        <table tableName="${table.name}"
               domainObjectName=""
               enableInsert="true"
               enableSelectByPrimaryKey="true"
               enableCountByExample="false"
               enableSelectByExample="false"
               selectByExampleQueryId="false"
               enableUpdateByPrimaryKey="true"
               enableUpdateByExample="false"
               enableDeleteByPrimaryKey="true"
               enableDeleteByExample="false"
        >
            <!--useActualColumnNames:
            (1)如果设置为true,那么MBG会使用从数据库元数据获取的列名作为生成的实体对象的属性。
            (2)如果为false(默认值),MGB将会尝试把返回的名称转换为驼峰形式。
            在这两种情况下,可以通过 元素显示指定,在这种情况下将会忽略这个(useActualColumnNames)属性。-->
            <property name="useActualColumnNames" value="false"/>
            <!-- 数据库表主键 -->
            <generatedKey column="id" sqlStatement="Mysql" identity="true"/>
        </table>
    </context>
</generatorConfiguration>

执行

import org.mybatis.generator.api.MyBatisGenerator;
import org.mybatis.generator.config.Configuration;
import org.mybatis.generator.config.xml.ConfigurationParser;
import org.mybatis.generator.internal.DefaultShellCallback;

import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

public class Generator {
    private boolean addRemarkComments = false;

    public static void main(String[] args) throws Exception {

        System.setProperty("jdbc.url", "jdbc:mysql://localhost:3306/electronic_ledger?serverTimezone=UTC");
        System.setProperty("jdbc.username", "root");
        System.setProperty("jdbc.password", "root");

        System.setProperty("entity.target.package", "com.ikeeper.entity.base");//实体类目录
        System.setProperty("mapper.xml.target.package", "mybatis-mapper.base");//mapper.xml 目录
        System.setProperty("mapper.class.target.package", "com.ikeeper.mapper.base");//mapper.class 目录


        System.setProperty("table.name", "ledger_task");//表名

        //MBG 执行过程中的警告信息
        List<String> warnings = new ArrayList<String>();
        //当生成的代码重复时,覆盖原代码
        boolean overwrite = true;
        //读取我们的 MBG 配置文件
        InputStream is = GeneratorMain.class.getResourceAsStream("/mybatis-generator.xml");
        ConfigurationParser cp = new ConfigurationParser(warnings);
        Configuration config = cp.parseConfiguration(is);
        is.close();

        DefaultShellCallback callback = new DefaultShellCallback(overwrite);
        //创建 MBG
        MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config, callback, warnings);
        //执行生成代码
        myBatisGenerator.generate(null);
        //输出警告信息
        for (String warning : warnings) {
            System.out.println(warning);
        }
    }
}