MyBatis逆向工程mybatis-generator

maven依赖

        <dependency>
            <groupId>org.mybatis.generator</groupId>
            <artifactId>mybatis-generator-core</artifactId>
            <version>${mybatis-generator.version}</version>
        </dependency>

MybatisGenerator插件是Mybatis官方提供的，这个插件存在一个固有的Bug，即当第一次生成了CategoryMapper.xml之后，再次运行会导致CategoryMapper.xml生成重复内容，而影响正常的运行。
为了解决这个问题，需要自己写一个小插件类OverIsMergeablePlugin

public class OverIsMergeablePlugin extends PluginAdapter {
    @Override
    public boolean validate(List<String> warnings) {
        return true;
    }

    @Override
    public boolean sqlMapGenerated(GeneratedXmlFile sqlMap, IntrospectedTable introspectedTable) {
        try {
            Field field = sqlMap.getClass().getDeclaredField("isMergeable");
            field.setAccessible(true);
            field.setBoolean(sqlMap, false);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return true;
    }
}

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>
    <!-- 数据库驱动 -->
    <classPathEntry location="mysql-connector-java-8.0.18.jar"/>

    <context id="DB2Tables" targetRuntime="MyBatis3">
        <!--避免生成重复代码的插件-->
        <plugin type="com.zl.tmall.util.OverIsMergeablePlugin"/>
        <commentGenerator>
            <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"/>
        </commentGenerator>

        <!--数据库链接URL，用户名、密码 -->
        <jdbcConnection driverClass="com.mysql.cj.jdbc.Driver"
                        connectionURL="jdbc:mysql://localhost:3306/zl_ssm?useSSL=false&amp;serverTimezone=UTC"
                        userId="root" password="root">
        </jdbcConnection>

        <!-- 默认false，把JDBC DECIMAL 和 NUMERIC 类型解析为 Integer;
         为 true时把JDBC DECIMAL和NUMERIC类型解析为java.math.BigDecimal -->
        <javaTypeResolver>
            <property name="forceBigDecimals" value="false"/>
        </javaTypeResolver>

        <!-- 生成pojo类存放位置 -->
        <javaModelGenerator targetPackage="com.zl.tmall.pojo" targetProject="src/main/java">
            <!-- enableSubPackages:是否让schema作为包的后缀 -->
            <property name="enableSubPackages" value="true"/>
            <!-- 清理前后的空格 -->
            <property name="trimStrings" value="true"/>
        </javaModelGenerator>

        <!-- 生成Mapper映射xml文件位置 -->
        <sqlMapGenerator targetPackage="mapper" targetProject="src/main/resources">
            <property name="enableSubPackages" value="true"/>
        </sqlMapGenerator>

        <!-- 生成Mapper接口文件位置 -->
        <javaClientGenerator type="XMLMAPPER" targetPackage="com.zl.tmall.mapper"
                             targetProject="src/main/java">
            <property name="enableSubPackages" value="true"/>
        </javaClientGenerator>

        <!-- 要生成哪些表(更改tableName和domainObjectName就可以) -->
        <!-- tableName:要生成的表名
            domainObjectName:生成后的实例名
            enableCountByExample:Count语句中加入where条件查询，默认为true开启
            enableUpdateByExample:Update语句中加入where条件查询，默认为true开启
            enableDeleteByExample:Delete语句中加入where条件查询，默认为true开启
            enableSelectByExample:Select多条语句中加入where条件查询，默认为true开启
            selectByExampleQueryId:Select单个对象语句中加入where条件查询，默认为true开启
        -->
        <table tableName="category" domainObjectName="Category" enableCountByExample="false"
               enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="true"
               selectByExampleQueryId="false">
            <property name="my.isgen.usekeys" value="true"/>
            <property name="useActualColumnNames" value="true"/>
            <generatedKey column="id" sqlStatement="JDBC"/>
        </table>

        <!--
        <table tableName="property" domainObjectName="Property" enableCountByExample="false"
               enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="true"
               selectByExampleQueryId="false">
            <property name="my.isgen.usekeys" value="true"/>
            <property name="useActualColumnNames" value="true"/>
            <generatedKey column="id" sqlStatement="JDBC"/>
        </table>

        <table tableName="product" domainObjectName="Product" enableCountByExample="false" enableUpdateByExample="false"
               enableDeleteByExample="false" enableSelectByExample="true" selectByExampleQueryId="false">
            <property name="my.isgen.usekeys" value="true"/>
            <property name="useActualColumnNames" value="true"/>
            <generatedKey column="id" sqlStatement="JDBC"/>
        </table>

        <table tableName="productImage" domainObjectName="ProductImage" enableCountByExample="false"
               enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="true"
               selectByExampleQueryId="false">
            <property name="my.isgen.usekeys" value="true"/>
            <property name="useActualColumnNames" value="true"/>
            <generatedKey column="id" sqlStatement="JDBC"/>
        </table>

        <table tableName="order_" domainObjectName="Order" enableCountByExample="false" enableUpdateByExample="false"
               enableDeleteByExample="false" enableSelectByExample="true" selectByExampleQueryId="false">
            <property name="my.isgen.usekeys" value="true"/>
            <property name="useActualColumnNames" value="true"/>
            <generatedKey column="id" sqlStatement="JDBC"/>
        </table>

        <table tableName="propertyValue" domainObjectName="PropertyValue" enableCountByExample="false"
               enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="true"
               selectByExampleQueryId="false">
            <property name="my.isgen.usekeys" value="true"/>
            <property name="useActualColumnNames" value="true"/>
            <generatedKey column="id" sqlStatement="JDBC"/>
        </table>

        <table tableName="review" domainObjectName="Review" enableCountByExample="false" enableUpdateByExample="false"
               enableDeleteByExample="false" enableSelectByExample="true" selectByExampleQueryId="false">
            <property name="my.isgen.usekeys" value="true"/>
            <property name="useActualColumnNames" value="true"/>
            <generatedKey column="id" sqlStatement="JDBC"/>
        </table>

        <table tableName="user" domainObjectName="User" enableCountByExample="false" enableUpdateByExample="false"
               enableDeleteByExample="false" enableSelectByExample="true" selectByExampleQueryId="false">
            <property name="my.isgen.usekeys" value="true"/>
            <property name="useActualColumnNames" value="true"/>
            <generatedKey column="id" sqlStatement="JDBC"/>
        </table>

        <table tableName="orderItem" domainObjectName="OrderItem" enableCountByExample="false"
               enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="true"
               selectByExampleQueryId="false">
            <property name="my.isgen.usekeys" value="true"/>
            <property name="useActualColumnNames" value="true"/>
            <generatedKey column="id" sqlStatement="JDBC"/>
        </table>
        -->
    </context>
</generatorConfiguration>

单独生成，可在桌面新建一个文件夹，使用命令行生成
cd 进入文件夹所在路径，然后使用下面的命令即可生成
Java -jar mybatis-generator-core-1.4.0.jar -configfile generatorConfig.xml -overwrite

编写逆向生成类

package util;

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.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

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

        String today = "2020-1-13";
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        Date now = sdf.parse(today);
        Date d = new Date();

        if(d.getTime() > now.getTime() + 1000*60*60*24){
            System.err.println("——————未成成功运行——————");
            System.err.println("——————未成成功运行——————");
            System.err.println("本程序具有破坏作用，应该只运行一次，如果必须要再运行，需要修改today变量为今天，如:" + sdf.format(new Date()));
            return;
        }
        if(false)
            return;

        List<String> warnings = new ArrayList<>();
        boolean overwrite = true;
        InputStream is= MybatisGenerator.class.getClassLoader().getResource("generatorConfig.xml").openStream();
        ConfigurationParser cp = new ConfigurationParser(warnings);
        Configuration config = cp.parseConfiguration(is);
        is.close();
        DefaultShellCallback callback = new DefaultShellCallback(overwrite);
        MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config, callback, warnings);
        myBatisGenerator.generate(null);

        System.out.println("生成代码成功，只能执行一次，以后执行会覆盖掉mapper,pojo,xml 等文件上做的修改");
    }
}