FreeMarker几种不同方式的展现数据

FreeMarker是一个模板引擎，一个基于模板生成文本输出的通用工具。

本文主要写了3种方法通过freemarker与java对象数据结合，将数据展现于前台页面。

注：项目jar包

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commons-beanutils-1.7.0.jar

commons-collections-3.1.jar

commons-fileupload-1.2.1.jar

commons-io-1.3.2.jar

commons-lang-2.5.jar

commons-logging-1.0.4.jar

ezmorph-1.0.6.jar

freemarker-2.3.13.jar

freemarker.jar

json-lib-2.4-jdk15.jar

ognl-2.6.11.jar

spring-core-2.0.8.jar

struts2-core-2.1.6.jar

xwork-2.1.2.jar

公共类：

User.java代码如下

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package com.hsinghsu.test.model;

public class User

{

private int id;

private String name;

private int age;

public String getName()

{

return name;

}

public void setName(String name)

{

this.name = name;

}

public int getId()

{

return id;

}

public void setId(int id)

{

this.id = id;

}

public int getAge()

{

return age;

}

public void setAge(int age)

{

this.age = age;

}

}

UserDao.java 代码如下，用于生成模拟数据：

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package com.hsinghsu.test.dao;

import java.util.ArrayList;

import java.util.List;

import com.hsinghsu.test.model.User;

public class UserDao

{

public List<User> getUserList()

{

List<User> list = new ArrayList<User>();

User user = null;

for (int i = 0; i < 10; i++)

{

user = new User();

user.setId(i);

user.setName("name" + i);

user.setAge(i + i);

list.add(user);

}

return list;

}

}

1.使用struts配置文件直接将数据渲染到ftl中

UserActionFTL.java Action代码如下：

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package com.hsinghsu.test.action;

import java.util.List;

import com.hsinghsu.test.dao.UserDao;

import com.hsinghsu.test.model.User;

import com.opensymphony.xwork2.ActionSupport;

/**

* 通过struts配置文件直接渲染ftl

* @author HsingHsu

*

*/

public class UserActionFTL extends ActionSupport

{

/**

*

*/

private static final long serialVersionUID = 1L;

private List<User> uList;

public String execute()

{

System.out.println("===begin");

UserDao userDao = new UserDao();

uList = userDao.getUserList();

return SUCCESS;

}

public List<User> getuList()

{

return uList;

}

public void setuList(List<User> uList)

{

this.uList = uList;

}

}

struts.xml配置文件如下：

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<?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE struts PUBLIC

"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"

"http://struts.apache.org/dtds/struts-2.0.dtd">

<struts>

<package name="hsinghsu" extends="struts-default">

<!-- 直接使用struts freemaker 将对象渲染到ftl中 -->

<action name="userListFTL" class="com.hsinghsu.test.action.UserActionFTL">

<result name="success" type="freemarker">/templates/userStrutsTemplate.ftl</result>

</action>

</package>

</struts>

userStrutsTemplate.ftl文件配置如下：

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<table style="text-align:center;FONT-SIZE: 11pt; WIDTH: 600px; FONT-FAMILY: 宋体; BORDER-COLLAPSE: collapse" borderColor=#3399ff cellSpacing=0 cellPadding=0 align=center border=1>

<tr>

<td><b>id</b></td>

<td><b>name</b></td>

<td><b>age</b></td>

</tr>

<#list uList as user>

<tr>

<td>${user.id}</td>

<td>${user.name}</td>

<td>${user.age}</td>

</tr>

</#list>

</table>

2.通过生成html文件，返回该html的url

FTL2HtmlFlie.java 通过ftl生成html文件类代码如下：

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package com.hsinghsu.test.util;

import java.io.BufferedWriter;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.OutputStreamWriter;

import java.io.UnsupportedEncodingException;

import java.io.Writer;

import java.util.Locale;

import java.util.Map;

import org.apache.struts2.ServletActionContext;

import freemarker.template.Configuration;

import freemarker.template.Template;

import freemarker.template.TemplateException;

public class FTL2HtmlFlie

{

/**

*

* @param ftlPath ftl的路径

* @param ftlName ftl的名称

* @param htmlPath 要生成的html路径

* @param htmlName 要生成的html名称

* @param dataMap 需要渲染到ftl中的map数据

* @return

*/

public static boolean createHtmlFile(String ftlPath, String ftlName,

String htmlPath, String htmlName, Map dataMap)

{

boolean result = false;

// 创建Configuration对象

Configuration cfg = new Configuration();

// 设置FreeMarker的模版文件位置

cfg.setServletContextForTemplateLoading(

ServletActionContext.getServletContext(), ftlPath);

cfg.setEncoding(Locale.getDefault(), "utf-8");

// 创建Template对象

Template template = null;

try

{

template = cfg.getTemplate(ftlName);

}

catch (IOException e1)

{

e1.printStackTrace();

}

template.setEncoding("utf-8");

String path = ServletActionContext.getServletContext().getRealPath("/");

File dir = new File(path + htmlPath);

if (!dir.exists())

{

dir.mkdirs();

}

File fileName = new java.io.File(path + htmlPath + htmlName);

System.out.println("html file:" + fileName.getPath());

Writer writer = null;

try

{

writer = new BufferedWriter(new OutputStreamWriter(

new FileOutputStream(fileName), "utf-8"));

}

catch (UnsupportedEncodingException e)

{

e.printStackTrace();

}

catch (FileNotFoundException e)

{

e.printStackTrace();

}

try

{

// 生成静态页面

template.process(dataMap, writer);

result = true;

}

catch (TemplateException e)

{

e.printStackTrace();

}

catch (IOException e)

{

e.printStackTrace();

}

try

{

writer.flush();

writer.close();

}

catch (IOException e)

{

e.printStackTrace();

}

return result;

}

}

UserActionHtmlFile.java Action代码如下：

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package com.hsinghsu.test.action;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import com.hsinghsu.test.dao.UserDao;

import com.hsinghsu.test.model.User;

import com.hsinghsu.test.util.FTL2HtmlFlie;

import com.opensymphony.xwork2.ActionSupport;

/**

* 生成html文件，返回html文件给前台

* @author HsingHsu

*

*/

public class UserActionHtmlFile extends ActionSupport

{

/**

*

*/

private static final long serialVersionUID = -16215231106028452L;

private String returnURL;

public String execute() throws Exception

{

UserDao userDao = new UserDao();

List<User> uList = userDao.getUserList();

Map<String, List<User>> dataMap = new HashMap<String, List<User>>();

dataMap.put("userList", uList);

String ftlPath = "/templates/";

String ftlName = "htmlFileTemplate.ftl";

String htmlPath = "/html/user/";

String htmlName = "user.html";

boolean result = FTL2HtmlFlie.createHtmlFile(ftlPath, ftlName,

htmlPath, htmlName, dataMap);

this.returnURL = htmlPath + htmlName;

if (result)

{

return SUCCESS;

}

else

{

return ERROR;

}

}

public String getReturnURL()

{

return returnURL;

}

public void setReturnURL(String returnURL)

{

this.returnURL = returnURL;

}

}

struts.xml配置文件如下：

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<?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE struts PUBLIC

"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"

"http://struts.apache.org/dtds/struts-2.0.dtd">

<struts>

<package name="hsinghsu" extends="struts-default">

<!-- 通过ftl生成html文件返回给用户 -->

<action name="userListHtmlFile" class="com.hsinghsu.test.action.UserActionHtmlFile">

<result type="redirect">${returnURL}</result>

</action>

</package>

</struts>

htmlFileTemplate.ftl文件配置如下：

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<table style="text-align:center;FONT-SIZE: 11pt; WIDTH: 600px; FONT-FAMILY: 宋体; BORDER-COLLAPSE: collapse" borderColor=#3399ff cellSpacing=0 cellPadding=0 align=center border=1>

<tr>

<td><b>id</b></td>

<td><b>name</b></td>

<td><b>age</b></td>

</tr>

<#list userList as user>

<tr>

<td>${user.id}</td>

<td>${user.name}</td>

<td>${user.age}</td>

</tr>

</#list>

</table>

3.通过ftl生成html字符串流，将生成的html字符串返回给前台。

FTL2String.java 通过ftl生成html字符串类代码如下：

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package com.hsinghsu.test.util;

import java.io.IOException;

import java.io.StringWriter;

import java.util.HashMap;

import java.util.Locale;

import java.util.Map;

import org.apache.struts2.ServletActionContext;

import freemarker.template.Configuration;

import freemarker.template.Template;

import freemarker.template.TemplateException;

/**

*

* @author HsingHsu

*

*/

public class FTL2String

{

/**

*

* @param ftlPath ftl的路径

* @param ftlName ftl的名称

* @param jsonDataString 需要渲染的json字符串

* @return

* @throws IOException

* @throws TemplateException

*/

public static String createHtmlString(String ftlPath, String ftlName,

String jsonDataString) throws IOException, TemplateException

{

String resultString;

// 创建Configuration对象

Configuration cfg = new Configuration();

// 设置FreeMarker的模版文件位置

cfg.setServletContextForTemplateLoading(

ServletActionContext.getServletContext(), ftlPath);

cfg.setEncoding(Locale.getDefault(), "utf-8");

// 创建Template对象

Template template = null;

template = cfg.getTemplate(ftlName);

template.setEncoding("utf-8");

Map<String, Object> context = new HashMap<String, Object>();

// 将json字符串加入数据模型

context.put("getData", jsonDataString);

// 输出流

StringWriter writer = new StringWriter();

// 将数据和模型结合生成html

template.process(context, writer);

// 获得html

resultString = writer.toString();

writer.close();

return resultString;

}

}

UserActionHtmlString.java Action代码如下：

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package com.hsinghsu.test.action;

import java.util.List;

import net.sf.json.JSONArray;

import com.hsinghsu.test.dao.UserDao;

import com.hsinghsu.test.model.User;

import com.hsinghsu.test.util.FTL2String;

import com.opensymphony.xwork2.ActionSupport;

/**

* 返回html流给前台

* @author HsingHsu

*

*/

public class UserActionHtmlString extends ActionSupport

{

/**

*

*/

private static final long serialVersionUID = 1006905813011288043L;

public String execute() throws Exception

{

UserDao userDao = new UserDao();

List<User> uList = userDao.getUserList();

// String jsonString =

// "{'userList': [{'id': 0,'name': 'name0','age': 0},{'id': 1,'name': 'name1','age': 2},{'id': 2,'name': 'name2','age': 2},{'id': 3,'name': 'name3','age': 2},{'id': 4,'name': 'name4','age': 2},{'id': 5,'name': 'name5','age': 2},{'id': 6,'name': 'name6','age': 2},{'id': 7,'name': 'name7','age': 2},{'id': 8,'name': 'name8','age': 2},{'id': 9,'name': 'name1','age': 2}]}";

String jsonString = JSONArray.fromObject(uList).toString();

// jsonString = JSONObject.fromObject(uList).toString();

System.out.println("json:" + jsonString);

// print:[{"age":0,"id":0,"name":"name0"},{"age":2,"id":1,"name":"name1"},{"age":4,"id":2,"name":"name2"},{"age":6,"id":3,"name":"name3"},{"age":8,"id":4,"name":"name4"},{"age":10,"id":5,"name":"name5"},{"age":12,"id":6,"name":"name6"},{"age":14,"id":7,"name":"name7"},{"age":16,"id":8,"name":"name8"},{"age":18,"id":9,"name":"name9"}]

String ftlPath = "/templates/";

String ftlName = "htmlStringTemplate.ftl";

String html = FTL2String.createHtmlString(ftlPath, ftlName, jsonString);

System.out.println("html:" + html);

return SUCCESS;

}

}

struts.xml配置文件如下，注：用户可根据不同的业务请求，来将html流展现给用户

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<?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE struts PUBLIC

"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"

"http://struts.apache.org/dtds/struts-2.0.dtd">

<struts>

<package name="hsinghsu" extends="struts-default">

<!-- 通过ftl生成html流返回给用户 -->

<action name="userListHtmlString" class="com.hsinghsu.test.action.UserActionHtmlString">

</action>

</package>

</struts>

htmlStringTemplate.ftl文件配置如下：

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<#assign data = getData?eval>

<table style="text-align:center;FONT-SIZE: 11pt; WIDTH: 600px; FONT-FAMILY: 宋体; BORDER-COLLAPSE: collapse" borderColor=#3399ff cellSpacing=0 cellPadding=0 align=center border=1>

<tr>

<td><b>id</b></td>

<td><b>name</b></td>

<td><b>age</b></td>

</tr>

<#list data as user>

<tr>

<td>${user.id}</td>

<td>${user.name}</td>

<td>${user.age}</td>

</tr>

</#list>

<#-- 注：jsonString = "{'userList': [{'id':******

<#list data.userList as user>

<tr>

<td>${user.id}</td>

<td>${user.name}</td>

<td>${user.age}</td>

</tr>

</#list>

-->

</table>