通常在开始开发项目的时候，首先会建立好数据库相关表，然后根据表结构生成 Controller、Service、DAO、Model以及一些前端页面。
如果开发前没有强制的约束，而每个程序员都有自己的编码习惯，最终会导致一个项目呈现出多种编码风格。再有就是一些CRUD的列表功能，基本是没啥挑战性的，纯粹苦力活，浪费时间。
所以，根据公司现有框架，开发一款统一风格的代码生成器还是很有必要的。
技术选型开发框架：SpringBoot+JPA，考虑到会生成各种前后端代码文件，这里我们选用freemarker模板引擎来制作相应的模板。
实现思路 获取表结构信息首先我们定义一个实体类，为了使用方便，把表和字段信息放到了一个类中：
@Data
public class AppGen extends PageBean implements Serializable {
private String tableName;
private String entityName;
private String lowerEntityName;
private String tableComment;
private String prefix;
private String function;
private String columnName;
private String entityColumnName;
private String columnComment;
private String dataType;
private Object columnExtra;
private Object columnLength;
private List list;
}
获取表列表：
@Override
@Transactional(readonly = true)
public Result list(AppGen gen){
String countSql = "SELECt COUNT(*) FROM information_schema.tables ";
countSql +="WHERe table_schema='tools'";
Long totalCount = dynamicQuery.nativeQueryCount(countSql);
PageBean data = new PageBean<>();
if(totalCount>0){
String nativeSql = "SELECt table_name as tableName,table_comment as tableComment ";
nativeSql+="FROM information_schema.tables WHERe table_schema='tools'";
Pageable pageable = PageRequest.of(gen.getPageNo(),gen.getPageSize());
List list = dynamicQuery.nativeQueryPagingListModel(AppGen.class,pageable, nativeSql);
data = new PageBean<>(list, totalCount);
}
return Result.ok(data);
}
制作模板
模板太多了，这里只以Controller模板为例，贴一下实现代码，更多模板见源码：
package com.tools.module.${prefix}.web;
import com.tools.common.config.AbstractController;
import com.tools.common.model.Result;
import com.tools.module.${prefix}.entity.${entityName};
import com.tools.module.${prefix}.service.${entityName}Service;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
@RequestMapping("/${prefix}/${function}")
public class ${entityName}Controller extends AbstractController {
@Autowired
private ${entityName}Service ${function}Service;
@PostMapping("/list")
public Result list(${entityName} ${function}){
return ${function}Service.list(${function});
}
@PostMapping("/get")
public Result get(Long id){
return ${function}Service.get(id);
}
@PostMapping("/save")
public Result save(@RequestBody ${entityName} ${function}){
return ${function}Service.save(${function});
}
@PostMapping("/delete")
public Result delete(Long id){
return ${function}Service.delete(id);
}
}
说白了其实就是传递参数，把一些可变的代码片段使用${name}形式编写。
代码生成有点长，慢慢看，其实就是渲染各种前后端模板：
@PostMapping("/create")
public Result create(@RequestBody AppGen gen) throws IOException, TemplateException {
List list = genService.getByTable(gen);
String name = gen.getTableName();
String[] table = StringUtils.split(name,"_");
gen.setPrefix(table[0]);
gen.setFunction(table[1]);
gen.setEntityName(GenUtils.allInitialCapital(gen.getTableName()));
list.stream().forEach(column-> {
column.setEntityColumnName(GenUtils.secInitialCapital(column.getColumnName()));
});
gen.setList(list);
String baseFile = filePath+ SystemConstant.SF_FILE_SEPARATOR+"com"+
SystemConstant.SF_FILE_SEPARATOR+ "tools"+
SystemConstant.SF_FILE_SEPARATOR+ "module"+
SystemConstant.SF_FILE_SEPARATOR+ gen.getPrefix()+SystemConstant.SF_FILE_SEPARATOR;
File entityFile = FileUtil.touch(baseFile+"entity"+
SystemConstant.SF_FILE_SEPARATOR+gen.getEntityName()+".java");
File repositoryFile = FileUtil.touch(baseFile+"repository"+
SystemConstant.SF_FILE_SEPARATOR+gen.getEntityName()+"Repository.java");
File serviceFile = FileUtil.touch(baseFile+"service"+
SystemConstant.SF_FILE_SEPARATOR+gen.getEntityName()+"Service.java");
File serviceImplFile = FileUtil.touch(baseFile+"service"+
SystemConstant.SF_FILE_SEPARATOR+"impl"+SystemConstant.SF_FILE_SEPARATOR+
gen.getEntityName()+"ServiceImpl.java");
File controllerFile = FileUtil.touch(baseFile+"web"+
SystemConstant.SF_FILE_SEPARATOR + gen.getEntityName() + "Controller.java");
String htmlPath = filePath+
SystemConstant.SF_FILE_SEPARATOR + "templates"+
SystemConstant.SF_FILE_SEPARATOR + gen.getPrefix()+
SystemConstant.SF_FILE_SEPARATOR + gen.getFunction()+SystemConstant.SF_FILE_SEPARATOR;
File listFile = FileUtil.touch(htmlPath + "list.html");
File formFile = FileUtil.touch(htmlPath + "form.html");
Template template = configuration.getTemplate("html/list.ftl");
String text = FreeMarkerTemplateUtils.processTemplateIntoString(
template, gen);
FileUtil.writeString(text,listFile,"UTF-8");
template = configuration.getTemplate("html/form.ftl");
text = FreeMarkerTemplateUtils.processTemplateIntoString(
template, gen);
FileUtil.writeString(text,formFile,"UTF-8");
template = configuration.getTemplate("java/repository.ftl");
text = FreeMarkerTemplateUtils.processTemplateIntoString(
template, gen);
FileUtil.writeString(text,repositoryFile,"UTF-8");
template = configuration.getTemplate("java/entity.ftl");
text = FreeMarkerTemplateUtils.processTemplateIntoString(
template, gen);
FileUtil.writeString(text,entityFile,"UTF-8");
template = configuration.getTemplate("java/service.ftl");
text = FreeMarkerTemplateUtils.processTemplateIntoString(
template, gen);
FileUtil.writeString(text,serviceFile,"UTF-8");
template = configuration.getTemplate("java/serviceImpl.ftl");
text = FreeMarkerTemplateUtils.processTemplateIntoString(
template, gen);
FileUtil.writeString(text,serviceImplFile,"UTF-8");
template = configuration.getTemplate("java/controller.ftl");
text = FreeMarkerTemplateUtils.processTemplateIntoString(
template, gen);
FileUtil.writeString(text,controllerFile,"UTF-8");
return Result.ok();
}
生成逻辑还是很傻瓜的，后期会慢慢优化，比如根据字段类型生成不同的表单形式，可以自定义字段是否显示等的。
小结总的来说，还是比较容易上手的，相对于一些简单的列表功能分分钟撸出效果，开发一分钟，喝茶一整天。当然对于一些复杂的效果，还是自己一一去实现。
源码https://gitee.com/52itstyle/SPTools
