这段时间的工作是做一个网址导航的项目，面向用户的就是一个首页，于是就想到了使用freemarker这个模板引擎来对首页静态化。
之前是用jsp实现，为了避免用户每次打开页面都查询一次数据库，所以使用了jsp的内置对象application，在Controller中将数据都查询出来，
然后放入application，最后在JSP页面使用jstl标签配合EL表达式 将数据遍历出来。这样做是从一定程度上减轻了服务器的压力和页面的响应速度，
但是仍然没有静态页面响应快。
使用Freemarker步骤：
- jar包，我的项目中使用maven来构建，所以在pom.xml中引入Freemarker jar包的坐标就可以了。
- ftl模板，我在WEB-INF下面创建一个文件夹ftl，里面只放ftl模板文件，我创建了一个index.ftl文件。
- ftl模板文件中写的就是html标签和css样式之类的，但是数据部分需要使用Freemarker提供的标签遍历出来。如下
???????????????????????<!--广告悬浮--> ???????????????????????<div class="subMenu"> ???????????????????????????<!--工具--> ???????????????????????????<div class=‘xff‘> ???????????????????????????????<div class="slideTxtBox"> ???????????????????????????????????<div class="hd"> ???????????????????????????????????????<span class="arrow"><a class="next"></a><a class="prev"></a></span> ???????????????????????????????????????<ul> ???????????????????????????????????????????<#list newsMap?keys as testKey> ???????????????????????????????????????????????<li>${testKey}</li> ???????????????????????????????????????????</#list> ???????????????????????????????????????</ul> ???????????????????????????????????</div> ???????????????????????????????????<div class="bd" style="padding: 5px 10px;"> ???????????????????????????????????????<#list newsMap?values as value> ???????????????????????????????????????????<div style="text-align: left; table-layout: fixed; word-wrap: break-word; width: 100%;" class="baidu"> ???????????????????????????????????????????<#list value as newsList> ???????????????????????????????????????????????<a target="_blank" href="${newsList.newsurl }" title="${newsList.newsname }">${newsList.newsname }</a> ???????????????????????????????????????????</#list> ???????????????????????????????????????????</div> ???????????????????????????????????????</#list> ???????????????????????????????????</div> ???????????????????????????????</div> ???????????????????????????</div> ???????????????????????</div>其中<#list></#list>是Freemarker提供的遍历标签，Freemarker提供了很多的标签，这里不一一叙述。
- Contorller中将数据都查询出来，通过ftl模板取出数据，最后将完整的数据写入html
???// 获取搜索引擎 ???????List<SearchEngines> searchEngines = this.indexService.findSearchEngines(); ???????// 获取热搜客户 ???????List<Catalog> hotSearchs = this.indexService.findHotSearchs(); ???????// 获取前25个一级目录 ???????CatalogCustom custom = new CatalogCustom(); ???????custom.setCatalogLevel(1); ???????List<Catalog> topLevelCatalog = this.indexService.findCustomers(custom); ???????// 获取一级目录下的前十个客户 ???????Map<String, List<Catalog>> customerMap = new HashMap<String, List<Catalog>>(); ???????????????for (Catalog catalog : topLevelCatalog) { ???????????CatalogCustom customer = new CatalogCustom(); ???????????customer.setCatalogLevel(3); ???????????customer.setGfid(catalog.getCatalogId()); ???????????????????????List<Catalog> customerList = this.indexService.findCustomers(customer); ???????????????????????????customerMap.put(catalog.getCatalogName(), customerList); ???????????????????????????????} ???????// 获取新闻相关数据 ???????Map<String, List<News>> newsMap = new HashMap<String, List<News>>(); ???????List<NewsCatalog> newsCatalogs = this.indexService.findNewsCatalog(); ???????????????for (NewsCatalog newsCatalog : newsCatalogs) { ???????????????????????News news = new News(); ???????????news.setPid(newsCatalog.getId()); ???????????List<News> newsList = this.indexService.findNews(news); ???????????????????????newsMap.put(newsCatalog.getNewscatalog(), newsList); ???????????????????} ???????// 获取关键词 ???????List<Keywords> keywords = this.indexService.findKeywords(); ???????/* ???????application.setAttribute("newsMap", newsMap); ???????application.setAttribute("searchEngines", searchEngines); ???????application.setAttribute("hotSearchs", hotSearchs); ???????application.setAttribute("customerMap", customerMap); ???????application.setAttribute("keywords", keywords); ???????*/ ???????????????String ftlPath = session.getServletContext().getRealPath("/WEB-INF/ftl"); ???????????????Configuration configuration = new Configuration(); ???????configuration.setDirectoryForTemplateLoading(new File(ftlPath)); ???????configuration.setDefaultEncoding("UTF-8"); ???????// 获取或创建一个模版。 ?????????Template template = configuration.getTemplate("index.ftl"); ???????// 获取html静态页面文件 ???????String indexPath = session.getServletContext().getRealPath("/index.html"); ???????//设置文件输入流编码，不然生成的html文件会中文乱码 ???????FileWriterWithEncoding out = new FileWriterWithEncoding(indexPath,"UTF-8"); ???????// 将页面中要展示的数据放入一个map中 ???????HashMap<String,Object> map = new HashMap<String, Object>(); ???????map.put("newsMap", newsMap); ???????map.put("searchEngines", searchEngines); ???????map.put("hotSearchs", hotSearchs); ???????map.put("customerMap", customerMap); ???????map.put("keywords", keywords); ???????//将map中的数据输入到index.ftl这个模板文件中并遍历出来，最后再将整个模板的数据写入到index.html中。 ???????template.process(map, out); ???????out.close();
Freemarker生成HTML静态页面
原文地址：https://www.cnblogs.com/panchanggui/p/10405640.html