Freemarker学习记录——基础部分

1、Freemarker介绍

FreeMarker是一个用Java语言编写的模板引擎，它基于模板来生成文本输出。FreeMarker与Web容器无关，即在Web运行时，它并不知道Servlet或HTTP。它不仅可以用作表现层的实现技术，而且还可以用于生成XML，JSP或Java 等。目前企业中:主要用Freemarker做静态页面或是页面展示。

使用Freemarker所用到的jar下载地址：http://freemarker.sourceforge.net/freemarkerdownload.html 

Maven坐标

<dependency><span style="white-space:pre"></span><groupId>freemarker</groupId><span style="white-space:pre"></span><artifactId>freemarker</artifactId><span style="white-space:pre"></span><version>2.3.18</version></dependency>

2、语法实例

• 首先创建一个java工程，并导入freemarker.jar包。再创建一个模板路径flt，并创建模板页面，创建一个静态页面存放路径freemarker。如图

图片代码

public class TestFM1 {public static void main(String[] args) throws Exception {// 实例化Freemarker的配置类Configuration con = new Configuration();// 第二步:给配置类设置路径File file = Paths.get("D:/java/TestFreemarker/flt/").toFile();con.setDirectoryForTemplateLoading(file);// 第三步:处理模板及数据之间 关系 将数据与模板合成一个html// 第四步: 输出htmlTemplate template = con.getTemplate("test1.html");File dFile = Paths.get("D:/java/TestFreemarker/freemarker/","freemarker.html").toFile();if (!dFile.exists()) {dFile.createNewFile();}Writer out = new FileWriter(dFile);// 定义数据Map<String, Object> rootMap = new HashMap<>();//输出hello worldString helloWorld = "Hello world !!";rootMap.put("world", helloWorld);template.process(rootMap, out);// 关闭流out.flush();out.close();}}

3、语法练习

1. 输出hello world

   //输出hello worldString helloWorld = "Hello world !!";rootMap.put("world", helloWorld);

   
   

   <!-- 输出Hello world -->${world}

   
   
2. 对象的输出

   //输出对象属性User user = new User();user.setUsername("张三");user.setAge(25);rootMap.put("user", user);

   
   

   <!-- 输出对象  -->  用户名 == ${user.username}<br/>年龄 == ${user.age}

   
   
3. 遍历List

   //遍历listList<String> listU = new ArrayList<>();listU.add("张三");listU.add("李四");listU.add("王五");listU.add("赵六");rootMap.put("listU", listU);

   
   

   <!-- 遍历list -->  <#list listU  as str>  ${str}  </#list>

   
   
4. 遍历map集合

   //遍历MapMap<String,Object> map = new HashMap<>();map.put("aa", "aa....");map.put("bb", 12);map.put("cc", 34.12);map.put("dd", "ddddd....");rootMap.put("mymap", map);

   
   

   <!-- 遍历map -->  ${mymap.aa}/${mymap.bb}/${mymap.cc}/${mymap.dd}    <#list mymap?keys as key>  ${key} == ${mymap[key]}  </#list>

   
   
5. 遍历List<Map>

   //遍历List<Map>List<Map<String, Object>> listMap = new ArrayList<>();Map<String,Object> map1 = new HashMap<>();map1.put("a1", "aaaaaaaaaa1");map1.put("b1", "bbbbbbbbbb1");map1.put("c1", "ccccccccccc1");Map<String,Object> map2 = new HashMap<>();map2.put("a1", "aaaaaaaaaa2");map2.put("b1", "bbbbbbbbbb2");map2.put("c1", "ccccccccccc2");listMap.add(map1);listMap.add(map2);rootMap.put("listMap", listMap);

   
   

     <!-- 遍历List<Map> -->   第一种方法：  <#list listMap as mymap>  ${mymap.a1}//${mymap.b1}//${mymap.c1}  </#list>    第二种：   <#list listMap as mymap>  <#list mymap?keys as key>  ${key}=${mymap[key]}  </#list>  </#list>

   
   
6. 获取索引

   //获取索引List<String> listIndex = new ArrayList<>();listIndex.add("AAAA");listIndex.add("BBB");listIndex.add("CCCCCCC");listIndex.add("DD");rootMap.put("listIndex", listIndex);

   
   

    <!-- 获取索引 -->  <#list listIndex as ind>   ${ind_index} = ${ind}  </#list>

   
   
7. 在模板中赋值

   <!-- 在模板中赋值 --> <#assign x=0/> ${x}      <#assign x="hahah"/> ${x}   <#assign x="${world}"/>  ${x}    <#assign x>  <#list ["zhouyi","zhouer","zhousan","zhousi","zhouwu"] as xx>  ${xx}  </#list>  </#assign>  ${x}

   
   
8. #if标签中 ==   !=   ||  &&  索引

   <!-- #if == != && || 索引 -->  <#list ["A","B","C","D","E","F","G","H"] as n>  <#if n == "A">  这个字母是：${n}  </#if>  <#if n != "A">  这个字母不是A，而是：${n}  </#if>  </#list>    <#list ["A","B","C","D","E","F","G","H"] as n>  <#if n_index != 0>  索引不等于0，${n}的索引为：${n_index}  </#if>  </#list>    <#list ["A","B","C","D","E","F","G","H"] as n>  <#if (n_index == 0) || (n_index == 3)>  ${n}的索引为：${n_index}  </#if>  </#list>

   
   
9. #else标签

   <!-- #else -->  <#list ["A","B","C","D","E","F","G","H"] as n>  <#if (n_index == 0) || (n_index == 3)>  ${n}的索引为：${n_index}  <#else>  ${n_index} --> ${n}  </#if>  </#list>

   
   
10. 时间格式

    rootMap.put("nowD", new Date());

    
    

      <!-- 时间格式 -->  1、date   2016-5-15  <span style="white-space:pre"></span>${nowD?date}  2、datetime   2016-5-15 17:28:30 <span style="white-space:pre"></span> ${nowD?datetime}  3、time   17:28:30 <span style="white-space:pre"></span> ${nowD?time}

    
    
11. null处理

    // null处理rootMap.put("vnull", null);

    
    

    <!-- null处理 -->  ${vnull!}  ${vnull!"我是null"}

    
    
12. 页面引入

    <!- -将另一个页面引入本页面时可用以下命令完成 --><#include "/include/head.html">