Freemarker学习

1.介绍freemarker、模板引擎

2.jsp与freemarker

 1 package freemarker;
 2 
 3 import java.io.IOException;
 4 import java.io.OutputStreamWriter;
 5 import java.util.Date;
 6 import java.util.HashMap;
 7 import java.util.Map;
 8 
 9 //import freemarker.entity.Computer;
10 
11 import freemarker.core.ParseException;
12 import freemarker.entity.Computer;
13 import freemarker.template.Configuration;
14 import freemarker.template.MalformedTemplateNameException;
15 import freemarker.template.Template;
16 import freemarker.template.TemplateException;
17 import freemarker.template.TemplateNotFoundException;
18 
19 public class FreemarkerSample1 {
20 
21     public static void main(String[] args) throws TemplateNotFoundException, MalformedTemplateNameException, ParseException, IOException, TemplateException {
22         //1. 加载模板
23         //创建核心配置对象
24         Configuration config = new Configuration(Configuration.VERSION_2_3_29);
25         //设置加载的目录
26         config.setClassForTemplateLoading(FreemarkerSample1.class, "");
27         //得到模板对象
28         Template t = config.getTemplate("sample1.ftl");
29         //2. 创建数据
30         Map<String,Object> data = new HashMap<String,Object>();
31         data.put("site", "新浪");
32         data.put("url", "http://www.sina.com");
33         data.put("date", new Date());
34         data.put("number", 837183.883217);
35         Map info = new HashMap();
36         info.put("cpu", "i5");
37         Computer c1 = new Computer("1234567" , "ThinkPad" , 1 , "李四" , new Date() , 12900f , info);
38         data.put("computer", c1);
39         //3. 产生输出
40         t.process(data, new OutputStreamWriter(System.out));
41     }
42 }

<#-- Freemarker取值 -->
${site}
${url}
<#-- !默认值 -->
${author!"不存在的属性"}
<#-- ?string格式化输出 -->
${date?string("yyyy年MM月dd日 HH:mm:ss SSS")}
${number?string("0.00")}
<#if computer.sn == "1234567">

3.if分支判断、switch分支判断

<#if computer.sn == "1234567">
重要设备
</#if>
SN:${computer.sn}
型号:${computer.model}
<#if computer.state == 1>
状态:正在使用
<#elseif computer.state == 2>
状态:闲置
<#elseif computer.state == 3>
状态:已作废
</#if>

<#switch computer.state>
    <#case 1>
        状态:正在使用
        <#break>
    <#case 2>
        状态:闲置
        <#break>
    <#case 3>
        状态:已作废
        <#break>
    <#default>
        状态:无效状态
</#switch>
<#-- ??代表判断对象是否为空,true不为空,false为空 -->
<#if computer.user??>
用户:${computer.user}
</#if>

4.list迭代列表、list迭代Map 、数字数列迭代

package freemarker;

import java.io.IOException;
import java.io.OutputStreamWriter;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

//import freemarker.entity.Computer;

import freemarker.core.ParseException;
import freemarker.entity.Computer;
import freemarker.template.Configuration;
import freemarker.template.MalformedTemplateNameException;
import freemarker.template.Template;
import freemarker.template.TemplateException;
import freemarker.template.TemplateNotFoundException;

public class FreemarkerSample2 {

    public static void main(String[] args) throws TemplateNotFoundException, MalformedTemplateNameException, ParseException, IOException, TemplateException {
        //1. 加载模板
        //创建核心配置对象
        Configuration config = new Configuration(Configuration.VERSION_2_3_29);
        //设置加载的目录
        config.setClassForTemplateLoading(FreemarkerSample2.class, "");
        //得到模板对象
        Template t = config.getTemplate("sample2.ftl");
        //2. 创建数据
        Map<String,Object> data = new HashMap<String,Object>();
        List<Computer> computers = new ArrayList();
        computers.add(new Computer("1234567" , "ThinkPad X1" , 2 , null , new Date() , 12999f , new HashMap() ));
        computers.add(new Computer("1234568" , "HP XXX" , 1 , "张三" , new Date() , 7500f , new HashMap() ));
        computers.add(new Computer("1234569" , "DELL XXX" , 3 , "李四" , new Date() , 8500f , new HashMap() ));
        computers.add(new Computer("1234570" , "ACER XXX" , 1 , "王五" , new Date() , 6300f , new HashMap() ));
        computers.add(new Computer("1234571" , "MSI XXX" , 1 , "赵六" , new Date() , 9300f , new HashMap() ));    
        data.put("computers", computers);
        //LinkedHashMap可以保证数据按存放顺序进行提取
        Map computerMap = new LinkedHashMap();
        for(Computer c : computers) {
            computerMap.put(c.getSn(), c);
        }
        data.put("computer_map", computerMap);
        //3. 产生输出
        t.process(data, new OutputStreamWriter(System.out));
    }
}

<#list computers as c>
序号:${c_index + 1} <#-- 迭代变量_index保存了循环的索引,从0开始 -->
SN:${c.sn}
型号:${c.model}
<#switch c.state>
<#case 1>
状态:使用中
<#break>
<#case 2>
状态:闲置
<#break>
<#case 3>
状态:已作废
<#break>
</#switch>
<#if c.user??>
用户:${c.user}
</#if>
采购日期:${c.dop?string("yyyy-MM-dd")}
采购价格:${c.price?string("0.00")}
-------------------------------------------
</#list>

<#list computer_map?keys as k >
${k}-${computer_map[k].model}
${computer_map[k].price?string("0.00")}
</#list>

5.内建函数

 1 package freemarker;
 2 
 3 import java.io.IOException;
 4 import java.io.OutputStreamWriter;
 5 import java.util.ArrayList;
 6 import java.util.Date;
 7 import java.util.HashMap;
 8 import java.util.LinkedHashMap;
 9 import java.util.List;
10 import java.util.Map;
11 
12 //import freemarker.entity.Computer;
13 
14 import freemarker.core.ParseException;
15 import freemarker.entity.Computer;
16 import freemarker.template.Configuration;
17 import freemarker.template.MalformedTemplateNameException;
18 import freemarker.template.Template;
19 import freemarker.template.TemplateException;
20 import freemarker.template.TemplateNotFoundException;
21 
22 public class FreemarkerSample3 {
23 
24     public static void main(String[] args) throws TemplateNotFoundException, MalformedTemplateNameException, ParseException, IOException, TemplateException {
25         //1. 加载模板
26         //创建核心配置对象
27         Configuration config = new Configuration(Configuration.VERSION_2_3_29);
28         //设置加载的目录
29         config.setClassForTemplateLoading(FreemarkerSample3.class, "");
30         //得到模板对象
31         Template t = config.getTemplate("sample3.ftl");
32         //2. 创建数据
33         Map<String,Object> data = new HashMap<String,Object>();
34         data.put("name", "jackson");
35         data.put("brand", "bmw");
36         data.put("words", "first blood");
37         data.put("n", 37981.83);
38         data.put("date", new Date());
39         List<Computer> computers = new ArrayList();
40         computers.add(new Computer("1234567" , "ThinkPad X1" , 2 , null , new Date() , 12999f , new HashMap() ));
41         computers.add(new Computer("1234568" , "HP XXX" , 1 , "张三" , new Date() , 7500f , new HashMap() ));
42         computers.add(new Computer("1234569" , "DELL XXX" , 3 , "李四" , new Date() , 8500f , new HashMap() ));
43         computers.add(new Computer("1234570" , "ACER XXX" , 1 , "王五" , new Date() , 6300f , new HashMap() ));
44         computers.add(new Computer("1234571" , "MSI XXX" , 1 , "赵六" , new Date() , 9300f , new HashMap() ));    
45         data.put("computers", computers);
46 
47         //3. 产生输出
48         t.process(data, new OutputStreamWriter(System.out));
49     }
50 }

${name?cap_first}
${brand?upper_case}
${brand?length}
${words?replace("blood" , "*****")}
${words?index_of("blood")}
<#-- 利用?string实现三目运算符的操作 -->
${(words?index_of("blood") != -1)?string("包含敏感词汇","不包含敏感词汇")}

${n?round}
${n?floor}
${n?ceiling}

公司共有${computers?size}台电脑
第一台:${computers?first.model}
最后一台:${computers?last.model}

<#list computers?sort_by("price")?reverse as c>
    ${c.sn}-${c.price}
</#list>

6.小练习

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
  <display-name>fm-web</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  <servlet>
      <servlet-name>freemarker</servlet-name>
      <servlet-class>freemarker.ext.servlet.FreemarkerServlet</servlet-class>
      <init-param>
          <param-name>TemplatePath</param-name>
          <param-value>/WEB-INF/ftl</param-value>
      </init-param>
  </servlet>
  <servlet-mapping>
      <servlet-name>freemarker</servlet-name>
      <url-pattern>*.ftl</url-pattern>
  </servlet-mapping>
</web-app>

 1 package freemarker;
 2 
 3 public class Employee {
 4     private int empno;
 5     private String ename;
 6     private String department;
 7     private String job;
 8     private Float salary;
 9     
10     public Employee(int empno, String ename, String department, String job, Float salary) {
11         super();
12         this.empno = empno;
13         this.ename = ename;
14         this.department = department;
15         this.job = job;
16         this.salary = salary;
17     }
18     public Integer getEmpno() {
19         return empno;
20     }
21     public void setEmpno(Integer empno) {
22         this.empno = empno;
23     }
24     public String getEname() {
25         return ename;
26     }
27     public void setEname(String ename) {
28         this.ename = ename;
29     }
30     public String getDepartment() {
31         return department;
32     }
33     public void setDepartment(String department) {
34         this.department = department;
35     }
36     public String getJob() {
37         return job;
38     }
39     public void setJob(String job) {
40         this.job = job;
41     }
42     public Float getSalary() {
43         return salary;
44     }
45     public void setSalary(Float salary) {
46         this.salary = salary;
47     }
48 }

 1 package freemarker;
 2 
 3 import java.io.IOException;
 4 import java.util.*;
 5 
 6 import javax.servlet.ServletException;
 7 import javax.servlet.annotation.WebServlet;
 8 import javax.servlet.http.HttpServlet;
 9 import javax.servlet.http.HttpServletRequest;
10 import javax.servlet.http.HttpServletResponse;
11 
12 
13 /**
14  * Servlet implementation class ListServlet
15  */
16 @WebServlet("/list")
17 public class ListServlet extends HttpServlet {
18     private static final long serialVersionUID = 1L;
19        
20     /**
21      * @see HttpServlet#HttpServlet()
22      */
23     public ListServlet() {
24         super();
25         // TODO Auto-generated constructor stub
26     }
27 
28     /**
29      * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
30      */
31     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
32         List list=new ArrayList();
33         list.add(new Employee(7731,"张三","市场部","客户代表",8000f));
34         list.add(new Employee(8871,"李四","研发部","运维工程师",7000f));
35         request.setAttribute("employee_list", list);
36         request.getRequestDispatcher("/employee.ftl").forward(request, response);
37     }
38 
39 }

 1 <!DOCTYPE html>
 2 <html>
 3 <head>
 4     <meta charset="UTF-8">
 5     <meta name="viewport" content="width=device-width,initial-scale=1">
 6     <title>员工列表</title>
 7     <link href="css/bootstrap.css" type="text/css" rel="stylesheet"></link>
 8     
 9     <script type="text/javascript" src="js/jquery-1.11.1.min.js"></script>
10     <script type="text/javascript" src="js/bootstrap.js"></script>
11 
12     <style type="text/css">
13         .pagination {
14             margin: 0px
15         }
16 
17         .pagination > li > a, .pagination > li > span {
18             margin: 0 5px;
19             border: 1px solid #dddddd;
20         }
21 
22         .glyphicon {
23             margin-right: 3px;
24         }
25 
26         .form-control[readonly] {
27             cursor: pointer;
28             background-color: white;
29         }
30         #dlgPhoto .modal-body{
31             text-align: center;
32         }
33         .preview{
34 
35             max- 500px;
36         }
37     </style>
38 </head>
39 <body>
40 
41 <div class="container">
42     <div class="row">
43         <h1 style="text-align: center">IMOOC员工信息表</h1>
44         <div class="panel panel-default">
45             <div class="clearfix panel-heading ">
46                 <div class="input-group" style=" 500px;">
47                     
48                 </div>
49             </div>
50 
51             <table class="table table-bordered table-hover">
52                 <thead>
53                 <tr>
54                     <th>序号</th>
55                     <th>员工编号</th>
56                     <th>姓名</th>
57                     <th>部门</th>
58                     <th>职务</th>
59                     <th>工资</th>
60                     <th>&nbsp;</th>
61                 </tr>
62                 </thead>
63                 <tbody>
64                 <#list employee_list as emp>
65                     <tr>
66                     <td>${emp_index+1}</td>
67                     <td>${emp.empno?string("0")}</td>
68                     <td>${emp.ename}</td>
69                     <td>${emp.department}</td>
70                     <td>${emp.job}</td>
71                     <td style="color: red;font-weight: bold">￥${emp.salary?string("0.00")}</td>      
72                 </tr>
73                 </#list>
74                 </tbody>
75             </table>
76         </div>
77     </div>
78 </div>
79 
80 </body>
81 </html>

效果显示：