<dependency> <groupId>com.baomidou</groupId> <artifactId>mybatis-plus-generator</artifactId> <version>3.5.2</version> </dependency> <dependency> <groupId>org.apache.velocity</groupId> <artifactId>velocity-engine-core</artifactId> <version>2.3</version> </dependency> <!--糊涂工具包--> <!-- https://mvnrepository.com/artifact/cn.hutool/hutool-core --> <dependency> <groupId>cn.hutool</groupId> <artifactId>hutool-core</artifactId> <version>5.7.20</version> </dependency> MyBatisPlus提高高度封装好的代码生成器模块，只需要简单的几行代码就能实现。同时也可以根据自己的需求灵活的通过模板话的方式生成代码。下面我们分别通过这两种方式来了解一些。
package com.didiplus; import com.baomidou.mybatisplus.generator.FastAutoGenerator; import com.baomidou.mybatisplus.generator.config.OutputFile; import org.junit.jupiter.api.Test; import java.util.Collections; /** * Author: didiplus * Email: 972479352@qq.com * CreateTime: 2022/5/6 * Desc:快速生成 */ public class FastAutoGeneratorTest { @Test public void fastAutoGeneratorTest(){ String url="jdbc:mysql://127.0.0.1:3306/didiadmin?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=true&serverTimezone=GMT%2B8&nullCatalogMeansCurrent=true"; FastAutoGenerator.create(url,"root","123456") .globalConfig(builder -> { builder.author("didiplus") // 设置作者 .enableSwagger() //开启 swagger 模式 .outputDir("D://autocode");// 指定输出目录 }) .packageConfig(builder -> { builder.parent("com.didiplus.models") // 设置父包名 .moduleName("sys") // 设置父包模块名 .pathInfo(Collections.singletonMap(OutputFile.xml,"D://autocode/xml")); }) .strategyConfig(builder -> { builder.addInclude("sys_dict_data") // 设置需要生成的表名 .addTablePrefix("t_","c_") ; // 设置过滤表前缀 }) // .templateEngine(new FreemarkerTemplateEngine()) 使用Freemarker引擎模板，默认的是Velocity引擎模板 .execute(); } } 运行以上代码，会自动的在D盘生成代码，但是，生成的代码只是最基本的模板。
以上生成的代码都是基于MybatisPlus代码生成默认模板去生成的。适合绝大多数场景。我们也可以根据自己的模板文件去生成代码的。
这些常量主要用户后期在组装模板时，把数据库类型转换成Java数据类型需要用到的。
package com.didiplus.constant; /** * Author: didiplus * Email: 972479352@qq.com * CreateTime: 2022/5/6 * Desc: 码 生 成 通 用 常 量 */ public class GenerateConstant { /** * 数据库字符串类型 */ public static final String[] COLUMN_TYPE_STR = {"char", "varchar", "nvarchar", "varchar2", "tinytext", "text", "mediumtext", "longtext"}; /** * 数据库时间类型 */ public static final String[] COLUMN_TYPE_TIME = {"datetime", "time", "date", "timestamp"}; /** * 数据库数字类型 */ public static final String[] COLUMN_TYPE_NUMBER = {"tinyint", "smallint", "mediumint", "int", "number", "integer", "bit"}; /** * 数据库bigint类型 */ public static final String[] COLUMN_TYPE_BIGINT = {"bigint"}; /** * 数据库float类型 */ public static final String[] COLUMN_TYPE_FLOAT = {"float"}; /** * 数据库double类型 */ public static final String[] COLUMN_TYPE_DOUBLE = {"double"}; /** * 数据库decimal类型 */ public static final String[] COLUMN_TYPE_DECIMAL = {"decimal"}; /** * 字符串类型 */ public static final String TYPE_STRING = "String"; /** * 整型 */ public static final String TYPE_INTEGER = "Integer"; /** * 长整型 */ public static final String TYPE_LONG = "Long"; /** * 浮点型 */ public static final String TYPE_DOUBLE = "Double"; /** * 高精度计算类型 */ public static final String TYPE_BIGDECIMAL = "BigDecimal"; /** * 时间类型 */ public static final String TYPE_DATE = "Date"; } /** * 全局配置 */ private GlobalConfig.Builder globalConfig() { String projectPath = System.getProperty("user.dir"); return new GlobalConfig.Builder() .fileOverride() // 覆盖已生成文件 .disableOpenDir() // 禁止打开输出目录 默认值:true .author("didiplus") //作者名 .outputDir(projectPath+"/src/main/resources/autocode") // 指定输出目录 .enableSwagger(); // 开启 swagger 模式 默认值:false } /** * 模板配置 */ private TemplateConfig.Builder templateConfig() { return new TemplateConfig.Builder() .entity("/templates/vm/entity.java") .mapper("/templates/vm/mapper.java") .service("/templates/vm/service.java") .serviceImpl("/templates/vm/serviceimpl.java") .controller("/templates/vm/controller.java") .xml("/templates/vm/mapper.xml"); } 以上的函数是声明代码生成根据这些模板去生成对应的模板。
/** * 包配置 */ private PackageConfig.Builder packageConfig() { return new PackageConfig.Builder() .parent(packageName) .moduleName(moduleName) .entity("domain.entity") .mapper("mapper") .service("service") .serviceImpl("service.impl") .xml("mapper.xml") .controller("controller"); } /** * 数据源配置 */ private static final DataSourceConfig DATA_SOURCE_CONFIG = new DataSourceConfig .Builder("jdbc:mysql://127.0.0.1:3306/didiadmin?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=true&serverTimezone=GMT%2B8&nullCatalogMeansCurrent=true","root","123456") .build(); /** * 策略配置 */ private StrategyConfig.Builder strategyConfig() { return new StrategyConfig.Builder() .addInclude(tableName); } /** * 注入配置 */ private InjectionConfig.Builder injectionConfig(){ Map<String, Object> map = new HashMap<>(); setAttr(tableName, DATA_SOURCE_CONFIG, map); return new InjectionConfig.Builder().customMap(map); } /** * 组装模板属性 * * @param tableName 表名 * @param dataSourceConfig 数据源 * @param map 模板里面 自定义的属性 * @param 表前缀 */ private void setAttr(String tableName, DataSourceConfig dataSourceConfig, Map<String, Object> map ){ List<Map<String, Object>> columns = new ArrayList<>(); // 获取表信息sql String tableSql = "select table_name , table_comment from information_schema.tables " + "where table_schema = (select database()) and table_name = '" + tableName + "'"; // 获取字段信息sql String columnSql = "select column_name , data_type , column_comment from information_schema.columns " + "where table_name = '" + tableName + "' and table_schema = (select database()) and column_name != 'id_new'"; // 利用现有的dataSourceConfig来获取数据库连接，查询表字段及备注等信息 try( Connection conn = dataSourceConfig.getConn(); PreparedStatement psTable = conn.prepareStatement(tableSql); ResultSet rsTable = psTable.executeQuery(); PreparedStatement pscolumns= conn.prepareStatement(columnSql); ResultSet rscolumns = pscolumns.executeQuery(); ){ if(rsTable.next()){ String table_name = rsTable.getString("table_name"); map.put("tableName",table_name); map.put("comment",rsTable.getString("table_comment")); // 类名 大驼峰 map.put("upperClassName", StrUtil.upperFirst(StrUtil.toCamelCase(table_name))); // 对象名 小驼峰 map.put("lowerClassName",StrUtil.toCamelCase(table_name)); } while (rscolumns.next()){ Map<String, Object> columnMap = new HashMap<>(); // 列名字、数据类型、java属性名字、java属性类型、备注 columnMap.put("column_name",rscolumns.getString("column_name")); columnMap.put("data_type",rscolumns.getString("data_type")); columnMap.put("javaLowerAttrName",StrUtil.toCamelCase(rscolumns.getString("column_name"))); columnMap.put("javaAttrType",columnTypeToJavaType(rscolumns.getString("data_type"))); columnMap.put("column_comment", rscolumns.getString("column_comment")); columns.add(columnMap); } } catch (Exception e) { log.info("----------sql执行出错"); e.printStackTrace(); } map.put("columns",columns); map.put("datetime", DateUtil.now()); map.put("packageName", packageName); map.put("moduleName", moduleName); } /** * 数据库类型转换为java类型 * * @param columnType 数据库类型 * @return java类型 */ private String columnTypeToJavaType(String columnType) { if(StrUtil.isNotEmpty(columnType)){ if(Arrays.asList(GenerateConstant.COLUMN_TYPE_STR).contains(columnType)){ return GenerateConstant.TYPE_STRING; } if(Arrays.asList(GenerateConstant.COLUMN_TYPE_TIME).contains(columnType)){ return GenerateConstant.TYPE_DATE; } if (Arrays.asList(GenerateConstant.COLUMN_TYPE_NUMBER).contains(columnType)) { return GenerateConstant.TYPE_INTEGER; } if (Arrays.asList(GenerateConstant.COLUMN_TYPE_BIGINT).contains(columnType)) { return GenerateConstant.TYPE_LONG; } if (Arrays.asList(GenerateConstant.COLUMN_TYPE_FLOAT).contains(columnType)) { return GenerateConstant.TYPE_DOUBLE; } if (Arrays.asList(GenerateConstant.COLUMN_TYPE_DOUBLE).contains(columnType)) { return GenerateConstant.TYPE_DOUBLE; } if (Arrays.asList(GenerateConstant.COLUMN_TYPE_DECIMAL).contains(columnType)) { return GenerateConstant.TYPE_BIGDECIMAL; } } return null; } 在项目的资源文件夹templats中创建vm文件夹存放模板文件
package ${packageName}.${moduleName}.domain.entity; #set($list=["createBy","createTime","createName", "updateBy", "updateName","updateTime", "deleteFlag"]) import com.didiplus.common.base.BaseDomain; import lombok.Data; import io.swagger.annotations.ApiModel; import io.swagger.annotations.ApiModelProperty; import java.util.Date; import com.baomidou.mybatisplus.annotation.TableName; /** * @author ${author} * @date ${datetime} * * @description ${comment}(${upperClassName}实体类) */ @Data @TableName("${tableName}") @ApiModel(value = "${comment}", description = "${comment}对象 ${lowerClassName}") public class ${upperClassName}Entity extends BaseDomain { #foreach ($column in $columns) ## 排除父类字段 #if($list.contains($column.javaLowerAttrName)) #else /** * $column.column_comment */ @ApiModelProperty(value = "$column.column_comment") private $column.javaAttrType $column.javaLowerAttrName; #end #end } package ${packageName}.${moduleName}.mapper; import com.baomidou.mybatisplus.core.mapper.BaseMapper; import ${packageName}.${moduleName}.domain.entity.${upperClassName}Entity; import org.apache.ibatis.annotations.Mapper; /** * @author ${author} * @date ${datetime} * * @description ${comment} */ @Mapper public interface ${upperClassName}Mapper extends BaseMapper<${upperClassName}Entity> { } <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="${packageName}.${moduleName}.mapper.${upperClassName}Mapper"> <resultMap id="${lowerClassName}Map" type="${packageName}.${moduleName}.domain.${upperClassName}"> #foreach($column in $columns) <result column="${column.column_name}" property="${column.javaLowerAttrName}"/> #end </resultMap> </mapper> package ${packageName}.${moduleName}.service; import com.baomidou.mybatisplus.core.metadata.IPage; import com.baomidou.mybatisplus.extension.service.IService; import ${packageName}.${moduleName}.domain.entity.${upperClassName}; import com.didiplus.common.web.domain.PageDomain; /** * @author ${author} * @date ${datetime} * * @description ${comment} */ public interface I${upperClassName}Service extends IService<${upperClassName}Entity> { /** * 分页查询 * @param pageDomain * @return */ IPage<${upperClassName}Entity> page(PageDomain pageDomain); } package ${packageName}.${moduleName}.service.impl; import com.didiplus.common.web.domain.PageDomain; import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl; import ${packageName}.${moduleName}.domain.entity.${upperClassName}Entity; import ${packageName}.${moduleName}.mapper.${upperClassName}Mapper; import ${packageName}.${moduleName}.service.I${upperClassName}Service; import org.springframework.stereotype.Service; import javax.annotation.Resource; import com.baomidou.mybatisplus.core.metadata.IPage; import com.baomidou.mybatisplus.extension.plugins.pagination.Page; /** * @author ${author} * @date ${datetime} * * @description ${comment} */ @Service public class ${upperClassName}ServiceImpl extends ServiceImpl<${upperClassName}Mapper, ${upperClassName}Entity> implements I${upperClassName}Service { @Resource ${upperClassName}Mapper ${lowerClassName}Mapper; @Override public IPage<${upperClassName}Entity> page(PageDomain pageDomain) { IPage<${upperClassName}Entity> page = new Page<>(pageDomain.getPage(),pageDomain.getLimit()); return ${lowerClassName}Mapper.selectPage(page,null); } } package ${packageName}.${moduleName}.controller; import com.baomidou.mybatisplus.core.metadata.IPage; import com.baomidou.mybatisplus.extension.plugins.pagination.Page; import ${packageName}.${moduleName}.domain.entity.${upperClassName}Entity; import ${packageName}.${moduleName}.service.I${upperClassName}Service; import io.swagger.annotations.Api; import io.swagger.annotations.ApiOperation; import lombok.extern.slf4j.Slf4j; import com.didiplus.common.web.domain.PageDomain; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.*; import com.didiplus.common.base.ValidGroup; import javax.annotation.Resource; /** * @author ${author} * @date ${datetime} * * @description ${comment} */ @Slf4j @RestController @RequestMapping("/${lowerClassName}") @Api(value = "${lowerClassName}", tags = "${comment}管理模块") public class ${upperClassName}Controller { @Resource private I${upperClassName}Service ${lowerClassName}Service; /** * 分页查询 * @param pageDomain 分页对象 * @param ${lowerClassName}Entity ${comment} * @return IPage */ @ApiOperation(value = "分页查询", notes = "分页查询") @GetMapping("/page") public IPage get${upperClassName}Page(@RequestBody PageDomain pageDomain) { return ${lowerClassName}Service.page(pageDomain); } /** * 新增${comment} * @param ${lowerClassName}Entity ${comment} * @return Result */ @ApiOperation(value = "新增${comment}", notes = "新增${comment}") @PostMapping public String save(@Validated(ValidGroup.Crud.Create.class) @RequestBody ${upperClassName}Entity ${lowerClassName}Entity) { return ${lowerClassName}Service.save(${lowerClassName}Entity)? "添加成功":"添加失败"; } /** * 修改${comment} * @param ${lowerClassName}Entity ${comment} * @return Result */ @ApiOperation(value = "修改${comment}", notes = "修改${comment}") @PutMapping public String updateById(@Validated(ValidGroup.Crud.Update.class) @RequestBody ${upperClassName}Entity ${lowerClassName}Entity) { return ${lowerClassName}Service.updateById(${lowerClassName}Entity)? "修改成功":"修改失败"; } /** * 通过id删除${comment} * @param id id * @return Result */ @ApiOperation(value = "通过id删除${comment}", notes = "通过id删除${comment}") @DeleteMapping("/{id}") public String removeById(@PathVariable Integer id) { return ${lowerClassName}Service.removeById(id)? "删除成功":"删除失败"; } } @Test public void generatorCode(){ AutoGenerator generator = new AutoGenerator(DATA_SOURCE_CONFIG); generator.strategy(strategyConfig().build()); generator.injection(injectionConfig().build()); generator.global(globalConfig().build()); generator.template(templateConfig().build()); generator.packageInfo(packageConfig().build()); generator.execute(); } 执行以上函数就可以自动生成代码了，如下图：
目前代码自动生成器只是一个脚本方式运行，后续我们会把它集成到页面上，通过图形界面的方式去操作。好了今天就分享到这里了，有什么问题欢迎留意。更多关注公众号“攻城狮成长日记”。
