随着MyBatis越来越深入人心，那么在使用Mybatis的时候，最最最麻烦的，莫过于是写Mapper。
幸好，万能的程序猿们已经开发出一套方便的工具，根据已有的数据库表来生成对应的JavaBean以及相应的一些Mapper

项目下载地址 [https://download.csdn.net/download/sail331x/13606703]

两个关键类
1、Generator类，程序入口

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;

/**
 * 数据库实体类生成器
 *
 * @Autor Shadow 2020/12/9
 * @Date 2020-12-09 10:32:55
 */
public class Generator {
    public static void main(String[] args) throws Exception {
        //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 = Generator.class.getResourceAsStream("/generatorConfig.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);
        }
    }
}

2、MyCommentGenerator注解生成类

import org.mybatis.generator.api.IntrospectedColumn;
import org.mybatis.generator.api.IntrospectedTable;
import org.mybatis.generator.api.dom.java.CompilationUnit;
import org.mybatis.generator.api.dom.java.Field;
import org.mybatis.generator.api.dom.java.FullyQualifiedJavaType;
import org.mybatis.generator.internal.DefaultCommentGenerator;
import org.mybatis.generator.internal.util.StringUtility;

import java.util.Properties;

/**
 * 自定义注释生成器
 * Created by macro on 2018/4/26.
 */
public class MyCommentGenerator extends DefaultCommentGenerator {
    private boolean addRemarkComments = false;
    private static final String EXAMPLE_SUFFIX = "Example";
    private static final String API_MODEL_PROPERTY_FULL_CLASS_NAME = "io.swagger.annotations.ApiModelProperty";

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

    /**
     * 给字段添加注释
     */
    @Override
    public void addFieldComment(Field field, IntrospectedTable introspectedTable,
                                IntrospectedColumn introspectedColumn) {
        String remarks = introspectedColumn.getRemarks();
        //根据参数和备注信息判断是否添加备注信息
        if (addRemarkComments && StringUtility.stringHasValue(remarks)) {
//            addFieldJavaDoc(field, 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swagger注解
            field.addJavaDocLine("@ApiModelProperty(value = \"" + remarks + "\")");
        }
    }

    /**
     * 给model的字段添加注释
     */
    private void addFieldJavaDoc(Field field, String remarks) {
        //文档注释开始
        field.addJavaDocLine("/**");
        //获取数据库字段的备注信息
        String[] remarkLines = remarks.split(System.getProperty("line.separator"));
        for (String remarkLine : remarkLines) {
            field.addJavaDocLine(" * " + remarkLine);
        }
//        addJavadocTag(field, false);
        field.addJavaDocLine(" */");
    }


    @Override
    public void addJavaFileComment(CompilationUnit compilationUnit) {
        super.addJavaFileComment(compilationUnit);
        //只在model中添加swagger注解类的导入
        if (!compilationUnit.isJavaInterface() && !compilationUnit.getType().getFullyQualifiedName().contains(EXAMPLE_SUFFIX)) {
            compilationUnit.addImportedType(new FullyQualifiedJavaType(API_MODEL_PROPERTY_FULL_CLASS_NAME));
        }
    }
}

3、配置文件 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>
    <properties resource="generator.properties"/>
    <context id="MySqlContext" targetRuntime="MyBatis3" defaultModelType="flat">
        <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"/>
        <commentGenerator type="xxx.xxx.xxx.MyCommentGenerator">
            <!-- 是否去除自动生成的注释 true：是 ： false:否 -->
            <property name="suppressAllComments" value="true"/>
            <property name="suppressDate" value="true"/>
            <property name="addRemarkComments" value="true"/>
        </commentGenerator>

        <jdbcConnection driverClass="${jdbc.driverClass}"
                        connectionURL="${jdbc.connectionURL}"
                        userId="${jdbc.username}"
                        password="${jdbc.password}">
            <!--解决mysql驱动升级到8.0后不生成指定数据库代码的问题-->
            <property name="nullCatalogMeansCurrent" value="true"/>
        </jdbcConnection>

        <javaModelGenerator targetPackage="xxx.xxx.xxx.entity" targetProject="xxx-project/src/main/java"/>

        <sqlMapGenerator targetPackage="xxx.xxx.xxx.mapper" targetProject="xxx-project/src/main/resources"/>

        <javaClientGenerator type="XMLMAPPER" targetPackage="xxx.xxx.xxx.mapper"
                             targetProject="xxx-project/src/main/java"/>
        <!--生成全部表tableName设为%-->
        <table tableName="%">
            <generatedKey column="id" sqlStatement="MySql" identity="true"/>
        </table>
    </context>
</generatorConfiguration>

4、generator.properties文件

jdbc.driverClass=com.mysql.cj.jdbc.Driver
jdbc.connectionURL=jdbc:mysql://127.0.0.1:3306/xxxxx?useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai
jdbc.username=root
jdbc.password=123456

5、pom文件 关键依赖（我这里是引入parent-module 所以版本写在其它地方 这里自己找对应版本就好）

    <dependencies>
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger-common</artifactId>
            <version>2.9.2</version>
        </dependency>
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper-spring-boot-starter</artifactId>
            <version>1.2.10</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.10</version>
        </dependency>
        <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>8.0.20</version>
        </dependency>
    </dependencies>

效果

生成的Entity

2、生成的Mapper