不知道大家有没有这样的感觉，在平时开发中，经常有很多dao、service类中存着很多重复的代码，Velocity提供了模板生成工具，今天我教大家怎么和这些大量的重复代码说再见。
注意参考项目：https://github.com/bigbeef/cppba-codeTemplate
个人博客：http://www.zhangbox.cn
大家可以写适合自己的模板，这里为了演示，就直接拿cppba-web的模板来示范，至于velocity的语法大家可以查看这篇文章：
工具集核心教程 | 第四篇： Velocity模板引擎入门到大神
创建模板文件org.apache.velocity velocity1.7
首先看下目录结构：
这里演示我就只贴出ServiceImplTemplate.java，需要其他模板代码可以到我github里面下载
#set ($domain = $!domainName.substring(0,1).toLowerCase()+$!domainName.substring(1))
package $!{packageName}.service.impl;
import $!{packageName}.core.bean.PageEntity;
import $!{packageName}.dao.$!{domainName}Dao;
import $!{packageName}.dto.$!{domainName}Dto;
import $!{packageName}.dto.baseDto;
import $!{packageName}.entity.$!{domainName};
import $!{packageName}.service.$!{domainName}Service;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import javax.annotation.Resource;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
@Service
@Transactional
public class $!{domainName}ServiceImpl implements $!{domainName}Service{
@Resource
private $!{domainName}Dao $!{domain}Dao;
@Override
public void save($!{domainName} $!{domain}) {
$!{domain}Dao.save($!{domain});
}
@Override
public void delete($!{domainName} $!{domain}) {
$!{domain}Dao.delete($!{domain});
}
@Override
public void update($!{domainName} $!{domain}) {
$!{domain}Dao.update($!{domain});
}
@Override
public $!{domainName} findById(int id) {
return ($!{domainName}) $!{domain}Dao.get($!{domainName}.class, id);
}
@Override
public PageEntity<$!{domainName}> query(baseDto baseDto) {
String hql = " select distinct $!{domain} from $!{domainName} $!{domain} where 1=1 ";
Map params = new HashMap();
$!{domainName}Dto $!{domain}Dto = ($!{domainName}Dto)baseDto;
$!{domainName} $!{domain} = $!{domain}Dto.get$!{domainName}();
int page = $!{domain}Dto.getPage();
int pageSize = $!{domain}Dto.getPageSize();
List list = $!{domain}Dao.query(hql,params,page,pageSize);
long count = $!{domain}Dao.count(hql,params);
PageEntity<$!{domainName}> pe = new PageEntity<$!{domainName}>();
pe.setCount(count);
pe.setList(list);
return pe;
}
}
模板生成
接下来是生成模板的主函数：
package com.cppba.core;
import org.apache.velocity.Template;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.Velocity;
import org.apache.velocity.app.VelocityEngine;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.OutputStreamWriter;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;
public class Main {
static String domainName = "Articles"; //类名
static String packageName = "com.cppba";//类包
static String templateDir = "\src\main\webapp\template\";
static String sourcePath = System.getProperty("user.dir")+templateDir;
static String resultDir = "\out";
static String targetPath = System.getProperty("user.dir")
+ resultDir + "\"
+ packageName.replace(".", "\");
public static void main(String []args) throws Exception{
Map map = new HashMap();
map.put("DaoTemplate.java","dao/" + domainName + "Dao.java");
map.put("ServiceTemplate.java","service/" + domainName + "Service.java");
map.put("ServiceImplTemplate.java","service/impl/" + domainName + "ServiceImpl.java");
map.put("DtoTemplate.java","dto/" + domainName + "Dto.java");
for(String templateFile:map.keySet()){
String targetFile = (String) map.get(templateFile);
Properties pro = new Properties();
pro.setProperty(Velocity.OUTPUT_ENCODING, "UTF-8");
pro.setProperty(Velocity.INPUT_ENCODING, "UTF-8");
pro.setProperty(Velocity.FILE_RESOURCE_LOADER_PATH, sourcePath);
VelocityEngine ve = new VelocityEngine(pro);
VelocityContext context = new VelocityContext();
context.put("domainName",domainName);
context.put("packageName",packageName);
Template t = ve.getTemplate(templateFile, "UTF-8");
File file = new File(targetPath, targetFile);
if (!file.getParentFile().exists())
file.getParentFile().mkdirs();
if (!file.exists())
file.createNewFile();
FileOutputStream outStream = new FileOutputStream(file);
OutputStreamWriter writer = new OutputStreamWriter(outStream,
"UTF-8");
BufferedWriter sw = new BufferedWriter(writer);
t.merge(context, sw);
sw.flush();
sw.close();
outStream.close();
System.out.println("成功生成Java文件:"
+ (targetPath + targetFile).replaceAll("/", "\\"));
}
}
}
生成java文件
我们可以修改domainName和packageName来修改我们的包名和类名，我们运行下看：
我们看到生成成功，我们打开ArticlesServiceImpl.java看下：
package com.cppba.service.impl;
import com.cppba.core.bean.PageEntity;
import com.cppba.dao.ArticlesDao;
import com.cppba.dto.ArticlesDto;
import com.cppba.dto.baseDto;
import com.cppba.entity.Articles;
import com.cppba.service.ArticlesService;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import javax.annotation.Resource;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
@Service
@Transactional
public class ArticlesServiceImpl implements ArticlesService{
@Resource
private ArticlesDao articlesDao;
@Override
public void save(Articles articles) {
articlesDao.save(articles);
}
@Override
public void delete(Articles articles) {
articlesDao.delete(articles);
}
@Override
public void update(Articles articles) {
articlesDao.update(articles);
}
@Override
public Articles findById(int id) {
return (Articles) articlesDao.get(Articles.class, id);
}
@Override
public PageEntity query(baseDto baseDto) {
String hql = " select distinct articles from Articles articles where 1=1 ";
Map params = new HashMap();
ArticlesDto articlesDto = (ArticlesDto)baseDto;
Articles articles = articlesDto.getArticles();
int page = articlesDto.getPage();
int pageSize = articlesDto.getPageSize();
List list = articlesDao.query(hql,params,page,pageSize);
long count = articlesDao.count(hql,params);
PageEntity pe = new PageEntity();
pe.setCount(count);
pe.setList(list);
return pe;
}
}
生成成功，我们拷贝到cppba-web中可完美运行！
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