入职没多久的年度总结刚入职没多久，连夜手写了一个代码生成器，项目开发速度瞬间屌炸了！

如果你想针对当前的项目开发一套定制化代码生成器，本文将给你答案！一、简介最近刚入职一个新团队，还没来得及熟悉业务，甲方爸爸就要求项目要在2个月内完成开发并上线！
本想着往后推迟1个月在交付，但是甲方爸爸不同意，只能赶鸭子上架了！
然后根据业务需求，设计出了大概30多张表，如果这30多张表，全靠开发人员手写 crud，开发所需的时间肯定会大大的延长，甚至可能直接会影响交付时间！
于是就想着，能不能通过代码生成器一键搞定全部的 crud？
本来计划是用mybatis-plus的，但是生成的代码，根据现有的框架标准，很多代码也需要自己改，有些地方还不如自己手写用的舒服，因此就决定手写一套代码生成器！
很多新手会觉得代码生成器很个高深的东西。其实不然，一点都不高深，当你看完本文的时候，你会完全掌握代码生成器的逻辑，甚至可以根据自己的项目情况，进行深度定制。
废话也不多说了，直接代码撸上！
二、实现思路下面我就以SpringBoot项目为例，数据持久化操作采用Mybatis，数据库采用Mysql，编写一个自动生成增、删、改、查等基础功能的代码生成器，内容包括controller、service、dao、entity、dto、vo等信息。
实现思路如下：

第一步：获取表字段名称、类型、表注释等信息
第二步：基于 freemarker 模板引擎，编写相应的模板
第三步：根据对应的模板，生成相应的 java 代码

2.1、获取表结构首先我们创建一张test_db表，脚本如下：

CREATE TABLE test_db (id bigint(20) unsigned NOT NULL COMMENT '主键ID',name varchar(50) COLLATE utf8mb4_unicode_ci NOT NULL DEFAULT '' COMMENT '名称',is_delete tinyint(4) NOT NULL DEFAULT '0' COMMENT '是否删除 1：已删除；0：未删除',create_time datetime NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间',update_time datetime NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '更新时间',PRIMARY KEY (id),KEY idx_create_time (create_time) USING BTREE) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='测试表';

表创建完成之后，基于test_db表，我们查询对应的表结果字段名称、类型、备注信息，这些信息收集将用于后续进行代码生成器所使用！

# 获取对应表结构SELECT column_name, data_type, column_comment FROM information_schema.columns WHERE table_schema = 'yjgj_base' AND table_name = 'test_db'

入职没多久的年度总结刚入职没多久，连夜手写了一个代码生成器，项目开发速度瞬间屌炸了！

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同时，获取对应表注释，用于生成备注信息！

# 获取对应表注释SELECT TABLE_COMMENT FROM INFORMATION_SCHEMA.TABLES WHERE table_schema = 'yjgj_base' AND table_name = 'test_db'

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2.2、编写模板

编写mapper模板，涵盖新增、修改、删除、查询等信息

<?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="${daoPackageName}.${daoName}">	<!--BaseResultMap-->	<resultMap id="BaseResultMap" type="${entityPackageName}.${entityName}"><#list columns as pro><#if pro.proName == primaryId><id column="${primaryId}" property="${primaryId}" jdbcType="${pro.fieldType}"/><#else><result column="${pro.fieldName}" property="${pro.proName}" jdbcType="${pro.fieldType}"/></#if></#list>	</resultMap>	<!--Base_Column_List-->	<sql id="Base_Column_List"><#list columns as pro><#if pro_index == 0>${pro.fieldName}<#else>,${pro.fieldName}</#if></#list>	</sql>	<!--批量插入-->	<insert id="insertList" parameterType="java.util.List">insert into ${tableName} (<#list columns as pro><#if pro_index == 0>${pro.fieldName},<#elseif pro_index == 1>${pro.fieldName}<#else>,${pro.fieldName}</#if></#list>)values<foreach collection ="list" item="obj" separator =","><trim prefix=" (" suffix=")" suffixOverrides=","><#list columns as pro>${r"#{obj." + pro.proName + r"}"},</#list></trim></foreach >	</insert>	<!--按需新增-->	<insert id="insertPrimaryKeySelective" parameterType="${entityPackageName}.${entityName}">insert into ${tableName}<trim prefix="(" suffix=")" suffixOverrides=","><#list columns as pro><if test="${pro.proName} != null">${pro.fieldName},</if></#list></trim><trim prefix="values (" suffix=")" suffixOverrides=","><#list columns as pro><if test="${pro.proName} != null">${r"#{" + pro.proName + r",jdbcType=" + pro.fieldType +r"}"},</if></#list></trim>	</insert>	<!-- 按需修改-->	<update id="updatePrimaryKeySelective" parameterType="${entityPackageName}.${entityName}">update ${tableName}<set><#list columns as pro><#if pro.fieldName != primaryId && pro.fieldName != primaryId><if test="${pro.proName} != null">${pro.fieldName} = ${r"#{" + pro.proName + r",jdbcType=" + pro.fieldType +r"}"},</if></#if></#list></set>where ${primaryId} = ${r"#{" + "${primaryId}" + r",jdbcType=BIGINT}"}	</update>	<!-- 按需批量修改-->	<update id="updateBatchByIds" parameterType="java.util.List">update ${tableName}<trim prefix="set" suffixOverrides=","><#list columns as pro><#if pro.fieldName != primaryId && pro.fieldName != primaryId><trim prefix="${pro.fieldName}=case" suffix="end,"><foreach collection="list" item="obj" index="index"><if test="obj.${pro.proName} != null">when id = ${r"#{" + "obj.id" + r"}"}then${r"#{obj." + pro.proName + r",jdbcType=" + pro.fieldType +r"}"}</if></foreach></trim></#if></#list></trim>where<foreach collection="list" separator="or" item="obj" index="index" >id = ${r"#{" + "obj.id" + r"}"}</foreach>	</update>	<!-- 删除-->	<delete id="deleteByPrimaryKey" parameterType="java.lang.Long">delete from ${tableName}where ${primaryId} = ${r"#{" + "${primaryId}" + r",jdbcType=BIGINT}"}	</delete>	<!-- 查询详情 -->	<select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Long">select<include refid="Base_Column_List"/>from ${tableName}where ${primaryId} = ${r"#{" + "${primaryId}" + r",jdbcType=BIGINT}"}	</select>	<!-- 按需查询 -->	<select id="selectByPrimaryKeySelective" resultMap="BaseResultMap" parameterType="${entityPackageName}.${entityName}">select<include refid="Base_Column_List"/>from ${tableName}	</select>	<!-- 批量查询-->	<select id="selectByIds" resultMap="BaseResultMap" parameterType="java.util.List">select<include refid="Base_Column_List"/>from ${tableName}<where><if test="ids != null">and ${primaryId} in<foreach item="item" index="index" collection="ids" open="(" separator="," close=")">${r"#{" + "item" + r"}"}</foreach></if></where>	</select>	<!-- 根据条件查询 -->	<select id="selectByMap" resultMap="BaseResultMap" parameterType="java.util.Map">select<include refid="Base_Column_List"/>from ${tableName}	</select>	<!-- 查询${entityName}总和 -->	<select id="countPage" resultType="int" parameterType="${dtoPackageName}.${dtoName}">select count(${primaryId})from ${tableName}	</select>	<!-- 查询${entityName}列表 -->	<select id="selectPage" resultMap="BaseResultMap" parameterType="${dtoPackageName}.${dtoName}">select<include refid="Base_Column_List"/>from ${tableName}limit ${r"#{" + "start,jdbcType=INTEGER" + r"}"},${r"#{" + "end,jdbcType=INTEGER" + r"}"}	</select></mapper>

编写dao数据访问模板

package ${daoPackageName};import com.example.generator.core.BaseMapper;import java.util.List;import ${entityPackageName}.${entityName};import ${dtoPackageName}.${dtoName};/**** @ClassName: ${daoName}* @Description: 数据访问接口* @author ${authorName}* @date ${currentTime}**/public interface ${daoName} extends BaseMapper<${entityName}>{	int countPage(${dtoName} ${dtoName?uncap_first});	List<${entityName}> selectPage(${dtoName} ${dtoName?uncap_first});}

编写service服务接口模板

package ${servicePackageName};import com.example.generator.core.BaseService;import com.example.generator.common.Pager;import ${voPackageName}.${voName};import ${dtoPackageName}.${dtoName};import ${entityPackageName}.${entityName};/** * * @ClassName: ${serviceName} * @Description: ${entityName}业务访问接口 * @author ${authorName} * @date ${currentTime} * */public interface ${serviceName} extends BaseService<${entityName}> {	/*** 分页列表查询* @param request*/	Pager<${voName}> getPage(${dtoName} request);}

编写serviceImpl服务实现类模板

package ${serviceImplPackageName};import com.example.generator.common.Pager;import com.example.generator.core.BaseServiceImpl;import com.example.generator.test.service.TestEntityService;import org.springframework.beans.BeanUtils;import org.springframework.stereotype.Service;import org.springframework.util.CollectionUtils;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import java.util.ArrayList;import java.util.List;import ${daoPackageName}.${daoName};import ${entityPackageName}.${entityName};import ${dtoPackageName}.${dtoName};import ${voPackageName}.${voName};@Servicepublic class ${serviceImplName} extends BaseServiceImpl<${daoName}, ${entityName}> implements ${serviceName} {	private static final Logger log = LoggerFactory.getLogger(${serviceImplName}.class);	/*** 分页列表查询* @param request*/	public Pager<${voName}> getPage(${dtoName} request) {List<${voName}> resultList = new ArrayList();int count = super.baseMapper.countPage(request);List<${entityName}> dbList = count > 0 ? super.baseMapper.selectPage(request) : new ArrayList<>();if(!CollectionUtils.isEmpty(dbList)){dbList.forEach(source->{${voName} target = new ${voName}();BeanUtils.copyProperties(source, target);resultList.add(target);});}return new Pager(request.getCurrPage(), request.getPageSize(), count, resultList);	}}

编写controller控制层模板

package ${controllerPackageName};import com.example.generator.common.IdRequest;import com.example.generator.common.Pager;import org.springframework.beans.BeanUtils;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.PostMapping;import org.springframework.web.bind.annotation.RequestBody;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;import java.util.Objects;import ${servicePackageName}.${serviceName};import ${entityPackageName}.${entityName};import ${dtoPackageName}.${dtoName};import ${voPackageName}.${voName};/** * * @ClassName: ${controllerName} * @Description: 外部访问接口 * @author ${authorName} * @date ${currentTime} * */@RestController@RequestMapping("/${entityName?uncap_first}")public class ${controllerName} {	@Autowired	private ${serviceName} ${serviceName?uncap_first};	/*** 分页列表查询* @param request*/	@PostMapping(value = "https://tazarkount.com/getPage")	public Pager<${voName}> getPage(@RequestBody ${dtoName} request){return ${serviceName?uncap_first}.getPage(request);	}	/*** 查询详情* @param request*/	@PostMapping(value = "https://tazarkount.com/getDetail")	public ${voName} getDetail(@RequestBody IdRequest request){${entityName} source = ${serviceName?uncap_first}.selectById(request.getId());if(Objects.nonNull(source)){${voName} result = new ${voName}();BeanUtils.copyProperties(source, result);return result;}return null;	}	/*** 新增操作* @param request*/	@PostMapping(value = "https://tazarkount.com/save")	public void save(${dtoName} request){${entityName} entity = new ${entityName}();BeanUtils.copyProperties(request, entity);${serviceName?uncap_first}.insert(entity);	}	/*** 编辑操作* @param request*/	@PostMapping(value = "https://tazarkount.com/edit")	public void edit(${dtoName} request){${entityName} entity = new ${entityName}();BeanUtils.copyProperties(request, entity);${serviceName?uncap_first}.updateById(entity);	}	/*** 删除操作* @param request*/	@PostMapping(value = "https://tazarkount.com/delete")	public void delete(IdRequest request){${serviceName?uncap_first}.deleteById(request.getId());	}}

编写entity实体类模板

package ${entityPackageName};import java.io.Serializable;import java.math.BigDecimal;import java.util.Date;/** * * @ClassName: ${entityName} * @Description: ${tableDes!}实体类 * @author ${authorName} * @date ${currentTime} * */public class ${entityName} implements Serializable {	private static final long serialVersionUID = 1L;<#--属性遍历-->	<#list columns as pro>	<#--<#if pro.proName != primaryId	&& pro.proName != 'remarks'	&& pro.proName != 'createBy'	&& pro.proName != 'createDate'	&& pro.proName != 'updateBy'	&& pro.proName != 'updateDate'	&& pro.proName != 'delFlag'	&& pro.proName != 'currentUser'	&& pro.proName != 'page'	&& pro.proName != 'sqlMap'	&& pro.proName != 'isNewRecord'	></#if>-->	/*** ${pro.proDes!}*/	private ${pro.proType} ${pro.proName};	</#list>	<#--属性get||set方法-->	<#list columns as pro>	public ${pro.proType} get${pro.proName?cap_first}() {return this.${pro.proName};	}	public ${entityName} set${pro.proName?cap_first}(${pro.proType} ${pro.proName}) {this.${pro.proName} = ${pro.proName};return this;	}	</#list>}

编写dto实体类模板

package ${dtoPackageName};import com.example.generator.core.BaseDTO;import java.io.Serializable;/** * @ClassName: ${dtoName} * @Description: 请求实体类 * @author ${authorName} * @date ${currentTime} * */public class ${dtoName} extends BaseDTO {}

编写vo视图实体类模板

package ${voPackageName};import java.io.Serializable;/** * @ClassName: ${voName} * @Description: 返回视图实体类 * @author ${authorName} * @date ${currentTime} * */public class ${voName} implements Serializable {	private static final long serialVersionUID = 1L;}

可能细心的网友已经看到了，在模板中我们用到了BaseMapper、BaseService、BaseServiceImpl等等服务类。
之所以有这三个类，是因为在模板中，我们有大量的相同的方法名包括逻辑也相似，除了所在实体类不一样意以外，其他都一样，因此我们可以借助泛型类来将这些服务抽成公共的部分。

BaseMapper，主要负责将dao层的公共方法抽出来

package com.example.generator.core;import org.apache.ibatis.annotations.Param;import java.io.Serializable;import java.util.List;import java.util.Map;/** * @author pzblog * @Description * @since 2020-11-11 */public interface BaseMapper<T> {/*** 批量插入* @param list* @return*/int insertList(@Param("list") List<T> list);/*** 按需插入一条记录* @param entity* @return*/int insertPrimaryKeySelective(T entity);/*** 按需修改一条记录（通过主键ID）* @return*/int updatePrimaryKeySelective(T entity);/*** 批量按需修改记录（通过主键ID）* @param list* @return*/int updateBatchByIds(@Param("list") List<T> list);/*** 根据ID删除* @param id 主键ID* @return*/int deleteByPrimaryKey(Serializable id);/*** 根据ID查询* @param id 主键ID* @return*/T selectByPrimaryKey(Serializable id);/*** 按需查询* @param entity* @return*/List<T> selectByPrimaryKeySelective(T entity);/*** 批量查询* @param ids 主键ID集合* @return*/List<T> selectByIds(@Param("ids") List<? extends Serializable> ids);/*** 查询（根据 columnMap 条件）* @param columnMap 表字段 map 对象* @return*/List<T> selectByMap(Map<String, Object> columnMap);}

BaseService，主要负责将service层的公共方法抽出来

package com.example.generator.core;import java.io.Serializable;import java.util.List;import java.util.Map;/** * @author pzblog * @Description 服务类 * @since 2020-11-11 */public interface BaseService<T> {/*** 新增* @param entity* @return boolean*/boolean insert(T entity);/*** 批量新增* @param list* @return boolean*/boolean insertList(List<T> list);/*** 通过ID修改记录（如果想全部更新，只需保证字段都不为NULL）* @param entity* @return boolean*/boolean updateById(T entity);/*** 通过ID批量修改记录（如果想全部更新，只需保证字段都不为NULL）* @param list* @return boolean*/boolean updateBatchByIds(List<T> list);/*** 根据ID删除* @param id 主键ID* @return boolean*/boolean deleteById(Serializable id);/*** 根据ID查询* @param id 主键ID* @return*/T selectById(Serializable id);/*** 按需查询* @param entity* @return*/List<T> selectByPrimaryKeySelective(T entity);/*** 批量查询* @param ids* @return*/List<T> selectByIds(List<? extends Serializable> ids);/*** 根据条件查询* @param columnMap* @return*/List<T> selectByMap(Map<String, Object> columnMap);}

BaseServiceImpl，service层的公共方法具体实现类

package com.example.generator.core;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.transaction.annotation.Transactional;import java.io.Serializable;import java.util.List;import java.util.Map;/** * @author pzblog * @Description 实现类（ 泛型说明：M 是 mapper 对象，T 是实体） * @since 2020-11-11 */public abstract class BaseServiceImpl<M extends BaseMapper<T>, T> implements BaseService<T>{@Autowiredprotected M baseMapper;/*** 新增* @param entity* @return boolean*/@Override@Transactional(rollbackFor = {Exception.class})public boolean insert(T entity){return returnBool(baseMapper.insertPrimaryKeySelective(entity));}/*** 批量新增* @param list* @return boolean*/@Override@Transactional(rollbackFor = {Exception.class})public boolean insertList(List<T> list){return returnBool(baseMapper.insertList(list));}/*** 通过ID修改记录（如果想全部更新，只需保证字段都不为NULL）* @param entity* @return boolean*/@Override@Transactional(rollbackFor = {Exception.class})public boolean updateById(T entity){return returnBool(baseMapper.updatePrimaryKeySelective(entity));}/*** 通过ID批量修改记录（如果想全部更新，只需保证字段都不为NULL）* @param list* @return boolean*/@Override@Transactional(rollbackFor = {Exception.class})public boolean updateBatchByIds(List<T> list){return returnBool(baseMapper.updateBatchByIds(list));}/*** 根据ID删除* @param id 主键ID* @return boolean*/@Override@Transactional(rollbackFor = {Exception.class})public boolean deleteById(Serializable id){return returnBool(baseMapper.deleteByPrimaryKey(id));}/*** 根据ID查询* @param id 主键ID* @return*/@Overridepublic T selectById(Serializable id){return baseMapper.selectByPrimaryKey(id);}/*** 按需查询* @param entity* @return*/@Overridepublic List<T> selectByPrimaryKeySelective(T entity){return baseMapper.selectByPrimaryKeySelective(entity);}/*** 批量查询* @param ids* @return*/@Overridepublic List<T> selectByIds(List<? extends Serializable> ids){return baseMapper.selectByIds(ids);}/*** 根据条件查询* @param columnMap* @return*/@Overridepublic List<T> selectByMap(Map<String, Object> columnMap){return baseMapper.selectByMap(columnMap);}/*** 判断数据库操作是否成功* @param result 数据库操作返回影响条数* @return boolean*/protected boolean returnBool(Integer result) {return null != result && result >= 1;}}

在此，还封装来其他的类，例如 dto 公共类BaseDTO，分页类Pager，还有 id 请求类IdRequest 。

BaseDTO公共类

public class BaseDTO implements Serializable {/*** 请求token*/private String token;/*** 当前页数*/private Integer currPage = 1;/*** 每页记录数*/private Integer pageSize = 20;/*** 分页参数（第几行）*/private Integer start;/*** 分页参数（行数）*/private Integer end;/*** 登录人ID*/private String loginUserId;/*** 登录人名称*/private String loginUserName;public String getToken() {return token;}public BaseDTO setToken(String token) {this.token = token;return this;}public Integer getCurrPage() {return currPage;}public BaseDTO setCurrPage(Integer currPage) {this.currPage = currPage;return this;}public Integer getPageSize() {return pageSize;}public BaseDTO setPageSize(Integer pageSize) {this.pageSize = pageSize;return this;}public Integer getStart() {if (this.currPage != null && this.currPage > 0) {start = (currPage - 1) * getPageSize();return start;}return start == null ? 0 : start;}public BaseDTO setStart(Integer start) {this.start = start;return this;}public Integer getEnd() {return getPageSize();}public BaseDTO setEnd(Integer end) {this.end = end;return this;}public String getLoginUserId() {return loginUserId;}public BaseDTO setLoginUserId(String loginUserId) {this.loginUserId = loginUserId;return this;}public String getLoginUserName() {return loginUserName;}public BaseDTO setLoginUserName(String loginUserName) {this.loginUserName = loginUserName;return this;}}

Pager分页类

public class Pager<T extends Serializable> implements Serializable {private static final long serialVersionUID = -6557244954523041805L;/*** 当前页数*/private int currPage;/*** 每页记录数*/private int pageSize;/*** 总页数*/private int totalPage;/*** 总记录数*/private int totalCount;/*** 列表数据*/private List<T> list;public Pager(int currPage, int pageSize) {this.currPage = currPage;this.pageSize = pageSize;}public Pager(int currPage, int pageSize, int totalCount, List<T> list) {this.currPage = currPage;this.pageSize = pageSize;this.totalPage = (int) Math.ceil((double) totalCount / pageSize);;this.totalCount = totalCount;this.list = list;}public int getCurrPage() {return currPage;}public Pager setCurrPage(int currPage) {this.currPage = currPage;return this;}public int getPageSize() {return pageSize;}public Pager setPageSize(int pageSize) {this.pageSize = pageSize;return this;}public int getTotalPage() {return totalPage;}public Pager setTotalPage(int totalPage) {this.totalPage = totalPage;return this;}public int getTotalCount() {return totalCount;}public Pager setTotalCount(int totalCount) {this.totalCount = totalCount;return this;}public List<T> getList() {return list;}public Pager setList(List<T> list) {this.list = list;return this;}}

IdRequest公共请求类

public class IdRequest extends BaseDTO {private Long id;public Long getId() {return id;}public IdRequest setId(Long id) {this.id = id;return this;}}

2.3、编写代码生成器前两部分主要介绍的是如何获取对应的表结构，以及代码器运行之前的准备工作。
其实代码生成器，很简单，其实就是一个main方法，没有想象中的那么复杂。
处理思路也很简单，过程如下：

1、定义基本变量，例如包名路径、模块名、表名、转换后的实体类、以及数据库连接配置，我们可以将其写入配置文件
2、读取配置文件，封装对应的模板中定义的变量
3、根据对应的模板文件和变量，生成对应的java文件

2.3.1、创建配置文件，定义变量小编我用的是application.properties配置文件来定义变量，这个没啥规定，你也可以自定义文件名，内容如下：

#包前缀packageNamePre=com.example.generator#模块名称moduleName=test#表tableName=test_db#实体类名称entityName=TestEntity#主键IDprimaryId=id#作者authorName=pzblog#数据库名称databaseName=yjgj_base#数据库服务器IP地址ipName=127.0.0.1#数据库服务器端口portName=3306#用户名userName=root#密码passWord=123456#文件输出路径，支持自定义输出路径，如果为空，默认取当前工程的src/main/java路径outUrl=

2.3.2、根据模板生成对应的java代码

首先，读取配置文件变量

public class SystemConstant {private static Properties properties = new Properties();static {try {// 加载上传文件设置参数：配置文件properties.load(SystemConstant.class.getClassLoader().getResourceAsStream("application.properties"));} catch (IOException e) {e.printStackTrace();}}public static final String tableName = properties.getProperty("tableName");public static final String entityName = properties.getProperty("entityName");public static final String packageNamePre = properties.getProperty("packageNamePre");public static final String outUrl = properties.getProperty("outUrl");public static final String databaseName = properties.getProperty("databaseName");public static final String ipName = properties.getProperty("ipName");public static final String portName = properties.getProperty("portName");public static final String userName = properties.getProperty("userName");public static final String passWord = properties.getProperty("passWord");public static final String authorName = properties.getProperty("authorName");public static final String primaryId = properties.getProperty("primaryId");public static final String moduleName = properties.getProperty("moduleName");}

然后，封装对应的模板中定义的变量

public class CodeService {public void generate(Map<String, Object> templateData) {//包前缀String packagePreAndModuleName = getPackagePreAndModuleName(templateData);//支持对应实体插入在前面，需要带上%stemplateData.put("entityPackageName", String.format(packagePreAndModuleName + ".entity",templateData.get("entityName").toString().toLowerCase()));templateData.put("dtoPackageName", String.format(packagePreAndModuleName + ".dto",templateData.get("entityName").toString().toLowerCase()));templateData.put("voPackageName", String.format(packagePreAndModuleName + ".vo",templateData.get("entityName").toString().toLowerCase()));templateData.put("daoPackageName", String.format(packagePreAndModuleName + ".dao",templateData.get("entityName").toString().toLowerCase()));templateData.put("mapperPackageName", packagePreAndModuleName + ".mapper");templateData.put("servicePackageName", String.format(packagePreAndModuleName + ".service",templateData.get("entityName").toString().toLowerCase()));templateData.put("serviceImplPackageName", String.format(packagePreAndModuleName + ".service.impl",templateData.get("entityName").toString().toLowerCase()));templateData.put("controllerPackageName", String.format(packagePreAndModuleName + ".web",templateData.get("entityName").toString().toLowerCase()));templateData.put("apiTestPackageName", String.format(packagePreAndModuleName + ".junit",templateData.get("entityName").toString().toLowerCase()));templateData.put("currentTime", new SimpleDateFormat("yyyy-MM-dd").format(new Date()));//======================生成文件配置======================try {// 生成EntityString entityName = String.format("%s", templateData.get("entityName").toString());generateFile("entity.ftl", templateData, templateData.get("entityPackageName").toString(), entityName+".java");// 生成dtoString dtoName = String.format("%sDTO", templateData.get("entityName").toString());templateData.put("dtoName", dtoName);generateFile("dto.ftl", templateData, templateData.get("dtoPackageName").toString(),dtoName + ".java");// 生成VOString voName = String.format("%sVO", templateData.get("entityName").toString());templateData.put("voName", voName);generateFile("vo.ftl", templateData, templateData.get("voPackageName").toString(),voName + ".java");// 生成DAOString daoName = String.format("%sDao", templateData.get("entityName").toString());templateData.put("daoName", daoName);generateFile("dao.ftl", templateData, templateData.get("daoPackageName").toString(),daoName + ".java");// 生成MapperString mapperName = String.format("%sMapper", templateData.get("entityName").toString());generateFile("mapper.ftl", templateData, templateData.get("mapperPackageName").toString(),mapperName+".xml");// 生成ServiceString serviceName = String.format("%sService", templateData.get("entityName").toString());templateData.put("serviceName", serviceName);generateFile("service.ftl", templateData, templateData.get("servicePackageName").toString(),serviceName + ".java");// 生成ServiceImplString serviceImplName = String.format("%sServiceImpl", templateData.get("entityName").toString());templateData.put("serviceImplName", serviceImplName);generateFile("serviceImpl.ftl", templateData, templateData.get("serviceImplPackageName").toString(),serviceImplName + ".java");// 生成ControllerString controllerName = String.format("%sController", templateData.get("entityName").toString());templateData.put("controllerName", controllerName);generateFile("controller.ftl", templateData, templateData.get("controllerPackageName").toString(),controllerName + ".java");//// 生成junit测试类//String apiTestName = String.format("%sApiTest", templateData.get("entityName").toString());//templateData.put("apiTestName", apiTestName);//generateFile("test.ftl", templateData, templateData.get("apiTestPackageName").toString(),//apiTestName + ".java");} catch (Exception e) {e.printStackTrace();}}/*** 生成文件* @param templateName 模板名称* @param templateData 参数名* @param packageName 包名* @param fileName 文件名*/public void generateFile(String templateName, Map<String, Object> templateData, String packageName, String fileName) {templateData.put("fileName", fileName);DaseService dbService = new DaseService(templateData);// 获取数据库参数if("entity.ftl".equals(templateName) || "mapper.ftl".equals(templateName)){dbService.getAllColumns(templateData);}try {// 默认生成文件的路径FreeMakerUtil freeMakerUtil = new FreeMakerUtil();freeMakerUtil.generateFile(templateName, templateData, packageName, fileName);} catch (Exception e) {e.printStackTrace();}}/*** 封装包名前缀* @return*/private String getPackagePreAndModuleName(Map<String, Object> templateData){String packageNamePre = templateData.get("packageNamePre").toString();String moduleName = templateData.get("moduleName").toString();if(StringUtils.isNotBlank(moduleName)){return packageNamePre + "." + moduleName;}return packageNamePre;}}

接着，获取模板文件，并生成相应的模板文件

public class FreeMakerUtil {/*** 根据Freemark模板，生成文件* @param templateName:模板名* @param root：数据原型* @throws Exception*/public void generateFile(String templateName, Map<String, Object> root, String packageName, String fileName) throws Exception {FileOutputStream fos=null;Writer out =null;try {// 通过一个文件输出流，就可以写到相应的文件中，此处用的是绝对路径String entityName = (String) root.get("entityName");String fileFullName = String.format(fileName, entityName);packageName = String.format(packageName, entityName.toLowerCase());String fileStylePackageName = packageName.replaceAll("\\.", "/");File file = new File(root.get("outUrl").toString() + "/" + fileStylePackageName + "/" + fileFullName);if (!file.getParentFile().exists()) {file.getParentFile().mkdirs();}file.createNewFile();Template template = getTemplate(templateName);fos = new FileOutputStream(file);out = new OutputStreamWriter(fos);template.process(root, out);out.flush();} catch (Exception e) {e.printStackTrace();} finally {try {if (fos != null){fos.close();}if(out != null){out.close();}} catch (IOException e) {e.printStackTrace();}}}/**** 获取模板文件** @param name* @return*/public Template getTemplate(String name) {try {Configuration cfg = new Configuration(Configuration.VERSION_2_3_23);cfg.setClassForTemplateLoading(this.getClass(), "/ftl");Template template = cfg.getTemplate(name);return template;} catch (IOException e) {e.printStackTrace();}return null;}}

最后，我们编写一个main方法，看看运行之后的效果

public class GeneratorMain {public static void main(String[] args) {System.out.println("生成代码start......");//获取页面或者配置文件的参数Map<String, Object> templateData = https://tazarkount.com/read/new HashMap();templateData.put("tableName", SystemConstant.tableName);System.out.println("表名=="+ SystemConstant.tableName);templateData.put("entityName", SystemConstant.entityName);System.out.println("实体类名称=="+ SystemConstant.entityName);templateData.put("packageNamePre", SystemConstant.packageNamePre);System.out.println("包名前缀=="+ SystemConstant.packageNamePre);//支持自定义输出路径if(StringUtils.isNotBlank(SystemConstant.outUrl)){templateData.put("outUrl", SystemConstant.outUrl);} else {String path = GeneratorMain.class.getClassLoader().getResource("").getPath() + "../../src/main/java";templateData.put("outUrl", path);}System.out.println("生成文件路径为=="+ templateData.get("outUrl"));templateData.put("authorName", SystemConstant.authorName);System.out.println("以后代码出问题找=="+ SystemConstant.authorName);templateData.put("databaseName", SystemConstant.databaseName);templateData.put("ipName", SystemConstant.ipName);templateData.put("portName", SystemConstant.portName);templateData.put("userName", SystemConstant.userName);templateData.put("passWord", SystemConstant.passWord);//主键IDtemplateData.put("primaryId", SystemConstant.primaryId);//模块名称templateData.put("moduleName", SystemConstant.moduleName);CodeService dataService = new CodeService();try {//生成代码文件dataService.generate(templateData);} catch (Exception e) {e.printStackTrace();}System.out.println("生成代码end......");}}

【入职没多久的年度总结刚入职没多久，连夜手写了一个代码生成器，项目开发速度瞬间屌炸了！】结果如下：

文章插图

生成的 Controller 层代码如下

/** * * @ClassName: TestEntityController * @Description: 外部访问接口 * @author pzblog * @date 2020-11-16 * */@RestController@RequestMapping("/testEntity")public class TestEntityController {	@Autowired	private TestEntityService testEntityService;	/*** 分页列表查询* @param request*/	@PostMapping(value = "https://tazarkount.com/getPage")	public Pager<TestEntityVO> getPage(@RequestBody TestEntityDTO request){return testEntityService.getPage(request);	}	/*** 查询详情* @param request*/	@PostMapping(value = "https://tazarkount.com/getDetail")	public TestEntityVO getDetail(@RequestBody IdRequest request){TestEntity source = testEntityService.selectById(request.getId());if(Objects.nonNull(source)){TestEntityVO result = new TestEntityVO();BeanUtils.copyProperties(source, result);return result;}return null;	}	/*** 新增操作* @param request*/	@PostMapping(value = "https://tazarkount.com/save")	public void save(TestEntityDTO request){TestEntity entity = new TestEntity();BeanUtils.copyProperties(request, entity);testEntityService.insert(entity);	}	/*** 编辑操作* @param request*/	@PostMapping(value = "https://tazarkount.com/edit")	public void edit(TestEntityDTO request){TestEntity entity = new TestEntity();BeanUtils.copyProperties(request, entity);testEntityService.updateById(entity);	}	/*** 删除操作* @param request*/	@PostMapping(value = "https://tazarkount.com/delete")	public void delete(IdRequest request){testEntityService.deleteById(request.getId());	}}

至此，一张单表的90%的基础工作量全部开发完毕！
三、总结代码生成器，在实际的项目开发中应用非常的广，本文主要以freemaker模板引擎为基础，开发的一套全自动代码生成器，一张单表的CRUD，只需要5秒钟就可以完成！
最后多说一句，如果你是项目中的核心开发，那么掌握代码生成器的规则，对项目开发效率的提升会有非常直观的帮助！
如果想要获取源代码，关注下方公众号，并回复【cccc4】即可获取！

作者：程序员志哥
出处：www.pzblog.cn
资源：微信搜【Java极客技术】关注我，回复【cccc】有我准备的一线程序必备计算机书籍、大厂面试资料和免费电子书。一共24G的资料，希望可以帮助大家提升技术和能力。

入职没多久的年度总结 刚入职没多久，连夜手写了一个代码生成器，项目开发速度瞬间屌炸了！

入职没多久的年度总结刚入职没多久，连夜手写了一个代码生成器，项目开发速度瞬间屌炸了！