MyBatis-Plus （简称 MP）是一个 MyBatis 的增强工具，在 MyBatis 的基础上只做增强不做改变，为简化开发、提高效率而生。
github地址：https://github.com/baomidou/mybatis-plus

今天主要介绍他的代码生成功能。其实官方文档已经写得很清楚了，这里做了些简单的封装。官方代码生成器文档：https://mybatis.plus/guide/generator.html。

mybatis-plus-generator：根据数据源中的表，反向生成controller、entity、service和mapper。

项目是作为一个整个maven项目的一个模块，结构如下：

首先是依赖，我用的是freemarker的模板，所以引入了org.freemarker，依赖如下：

    <dependencies><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-generator</artifactId><version>${mybatis.plus.version}</version></dependency><dependency><groupId>org.freemarker</groupId><artifactId>freemarker</artifactId><version>${freemarker.version}</version></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId></dependency></dependencies>

定义一个CodeGeneConfig类，里面是mybatis-plus-generator常用的配置属性，还有一个CodeGeneProps类，对应属性文件code.properties里面的key。分别如图：

@Data
public class CodeGeneConfig {private String geneModule;private String genePkgModule;private String genePkgParent;private String geneDsUrl;private String geneDsUsername;private String geneDsPassword;private String geneTableNames;private String geneTablePrefix;private String geneBaseEntity;private String geneBaseEntityFields;private String geneBaseController;private String geneEntityName;private String geneAuthor;
}

public interface CodeGeneProps {/*** 项目子模块*/String GENE_MODULE = "gene.module";/*** 所在包*/String GENE_PKG_MODULE = "gene.pkg.module";/*** 所在包的父包*/String GENE_PKG_PARENT = "gene.pkg.parent";/*** 数据源url*/String GENE_DS_URL = "gene.ds.url";/*** 数据源账号*/String GENE_DS_USERNAME = "gene.ds.username";/*** 数据源密码*/String GENE_DS_PASSWORD = "gene.ds.password";/*** 全部表名，多个用逗号分隔*/String GENE_TABLE_NAMES = "gene.table.names";/*** 表前缀，生成@TableName注解里的表前缀*/String GENE_TABLE_PREFIX = "gene.table.prefix";/*** entity的父类*/String GENE_BASE_ENTITY = "gene.base.entity";/*** entity父类的字段，多个用逗号分隔*/String GENE_BASE_ENTITY_FIELDS = "gene.base.entity.fields";/*** controller的父类*/String GENE_BASE_CONTROLLER = "gene.base.controller";/*** entity的类名*/String GENE_ENTITY_NAME = "gene.entity.name";/*** 注释中的author*/String GENE_AUTHOR = "gene.author";
}

gene.module=easy-starter-app
gene.pkg.module=system
gene.pkg.parent=me.heysgene.ds.url=jdbc:mysql://192.168.41.130:3306/trade?useUnicode=true&characterEncoding=utf-8
gene.ds.username=root
gene.ds.password=mysqlgene.table.names=t_user
gene.table.prefix=t_gene.base.entity=me.heys.core.base.BaseEntity
gene.base.entity.fields=id,create_user,create_time,update_time
gene.base.controller=gene.entity.name=%sEntity
gene.author=heys

最后就是CodeGenerator类，基本上是依照官方文档写的。CodeGeneConfig配置优先，如果没有配置，就读取code.properties里面的配置：

@Slf4j
public class CodeGenerator {private CodeGeneConfig config;public CodeGenerator(CodeGeneConfig config) {this.config = mergeProps(config);}private CodeGeneConfig mergeProps(CodeGeneConfig config) {if (null == config) {config = new CodeGeneConfig();}Properties props = new Properties();try {props.load(CodeGenerator.class.getClassLoader().getResourceAsStream("code.properties"));} catch (IOException e) {log.error("CodeGenerator读取配置失败", e);}if (StringUtil.isBlank(config.getGeneModule())) {config.setGeneModule(props.getProperty(CodeGeneProps.GENE_MODULE));}if (StringUtil.isBlank(config.getGenePkgModule())) {config.setGenePkgModule(props.getProperty(CodeGeneProps.GENE_PKG_MODULE));}if (StringUtil.isBlank(config.getGenePkgParent())) {config.setGenePkgParent(props.getProperty(CodeGeneProps.GENE_PKG_PARENT));}if (StringUtil.isBlank(config.getGeneDsUrl())) {config.setGeneDsUrl(props.getProperty(CodeGeneProps.GENE_DS_URL));}if (StringUtil.isBlank(config.getGeneDsUsername())) {config.setGeneDsUsername(props.getProperty(CodeGeneProps.GENE_DS_USERNAME));}if (StringUtil.isBlank(config.getGeneDsPassword())) {config.setGeneDsPassword(props.getProperty(CodeGeneProps.GENE_DS_PASSWORD));}if (StringUtil.isBlank(config.getGeneTableNames())) {config.setGeneTableNames(props.getProperty(CodeGeneProps.GENE_TABLE_NAMES));}if (StringUtil.isBlank(config.getGeneTablePrefix())) {config.setGeneTablePrefix(props.getProperty(CodeGeneProps.GENE_TABLE_PREFIX));}if (StringUtil.isBlank(config.getGeneBaseEntity())) {config.setGeneBaseEntity(props.getProperty(CodeGeneProps.GENE_BASE_ENTITY));}if (StringUtil.isBlank(config.getGeneBaseEntityFields())) {config.setGeneBaseEntityFields(props.getProperty(CodeGeneProps.GENE_BASE_ENTITY_FIELDS));}if (StringUtil.isBlank(config.getGeneBaseController())) {config.setGeneBaseController(props.getProperty(CodeGeneProps.GENE_BASE_CONTROLLER));}if (StringUtil.isBlank(config.getGeneEntityName())) {config.setGeneEntityName(props.getProperty(CodeGeneProps.GENE_ENTITY_NAME));}if (StringUtil.isBlank(config.getGeneAuthor())) {config.setGeneAuthor(props.getProperty(CodeGeneProps.GENE_AUTHOR));}return config;}public void execute() {// 代码生成器AutoGenerator generator = new AutoGenerator();// 全局配置GlobalConfig globalConfig = new GlobalConfig();StringBuilder builder = new StringBuilder(System.getProperty("user.dir"));if (StringUtil.isNotBlank(config.getGeneModule())) {builder.append("/" + config.getGeneModule());}builder.append("/src/main/java");globalConfig.setEntityName(config.getGeneEntityName());globalConfig.setOutputDir(builder.toString());globalConfig.setAuthor(config.getGeneAuthor());globalConfig.setOpen(false);generator.setGlobalConfig(globalConfig);// 数据源配置DataSourceConfig dataSourceConfig = new DataSourceConfig();dataSourceConfig.setUrl(config.getGeneDsUrl());dataSourceConfig.setSchemaName("public");dataSourceConfig.setDriverName("com.mysql.cj.jdbc.Driver");dataSourceConfig.setUsername(config.getGeneDsUsername());dataSourceConfig.setPassword(config.getGeneDsPassword());generator.setDataSource(dataSourceConfig);// 包配置PackageConfig packageConfig = new PackageConfig();packageConfig.setModuleName(config.getGenePkgModule());packageConfig.setParent(config.getGenePkgParent());generator.setPackageInfo(packageConfig);// 模板配置TemplateConfig templateConfig = new TemplateConfig();templateConfig.setXml(null);generator.setTemplate(templateConfig);InjectionConfig injectionConfig = new InjectionConfig() {@Overridepublic void initMap() {Map<String, Object> map = new HashMap<>();// 用来作为类注释的时间，模板中通过${cfg.datetime}获取map.put("datetime", new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()));this.setMap(map);}};generator.setCfg(injectionConfig);// 策略配置StrategyConfig strategy = new StrategyConfig();strategy.setNaming(NamingStrategy.underline_to_camel);strategy.setColumnNaming(NamingStrategy.underline_to_camel);if (StringUtil.isNotBlank(config.getGeneBaseEntity())) {strategy.setSuperEntityClass(config.getGeneBaseEntity());}strategy.setEntityLombokModel(true);strategy.setRestControllerStyle(true);if (StringUtil.isNotBlank(config.getGeneBaseController())) {strategy.setSuperControllerClass(config.getGeneBaseController());}strategy.setInclude(config.getGeneTableNames().split(","));String superFields = config.getGeneBaseEntityFields();if(StringUtil.isNotBlank(superFields)) {strategy.setSuperEntityColumns(superFields.split(","));}strategy.setControllerMappingHyphenStyle(true);strategy.setTablePrefix(config.getGeneTablePrefix());generator.setStrategy(strategy);generator.setTemplateEngine(new FreemarkerTemplateEngine());generator.execute();}
}

使用方式：

public class Generator {public static void main(String[] args) {CodeGeneConfig codeGeneConfig = new CodeGeneConfig();codeGeneConfig.setGeneModule("easy-starter-app");new CodeGenerator(codeGeneConfig).execute();}
}

mybatis-plus-generator的templates目录下是模板，稍微修改了一下模板：修改了注释、加了@Slf4j注解。
只需要把模板复制到自己代码resources/templates目录下，会自动读取。

这个模块可以打成一个jar包，在不同地方单独使用。如下效果：