freemarker集成maven的简单的应用

最新推荐文章于 2024-04-12 09:20:44 发布

ordinaryday

最新推荐文章于 2024-04-12 09:20:44 发布

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分类专栏： freemarker

本文链接：https://blog.youkuaiyun.com/jsaber/article/details/79010016

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本文介绍如何在Maven项目中集成Freemarker模板引擎，包括在pom.xml配置依赖，web.xml中设置服务，创建后端及前端项目，配置数据源，设计页面及模板，以及实现新闻页面的展示。

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1.创建本地maven项目，在pom.xml中配置freemarker的架包

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>cn</groupId>
  <artifactId>fmarker</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>
  
  <dependencies>
  	<!-- freemarker的架包 -->
  	<dependency>
  		 <groupId>org.freemarker</groupId>
 		 <artifactId>freemarker</artifactId>
 		 <version>2.3.23</version>
 	</dependency>
 	
  </dependencies>
</project>

2.在webapp的web-inf下的web.xml中配置freemarker的服务

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xmlns="http://java.sun.com/xml/ns/javaee" 
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5">
  <display-name>fmarker</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>
    
  <!-- 模板的查找路径  从上下文根路径查找 模板 ftl-->
  <init-param>
    <param-name>TemplatePath</param-name>
    <param-value>/</param-value>
  </init-param>
  <!-- 是否不需要缓存 -->
  <init-param>
    <param-name>NoCache</param-name>
    <param-value>true</param-value>
  </init-param>
  <!-- 最终显示是html -->
  <init-param>
    <param-name>ContentType</param-name>
    <param-value>text/html;charset=UTF-8</param-value>
  </init-param>
    
  <!-- FreeMarker settings: -->
  <init-param>
    <param-name>template_update_delay</param-name>
    <param-value>0</param-value> <!-- 0 is for development only! Use higher value otherwise. -->
  </init-param>
  <init-param>
    <param-name>default_encoding</param-name>
    <param-value>UTF-8</param-value>
  </init-param>
  <!-- 数字的格式 -->
  <init-param>
    <param-name>number_format</param-name>
    <param-value>0.##</param-value>
  </init-param>
  <!-- servlet 容器启动时实例化 -->
  <load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
  <servlet-name>freemarker</servlet-name>
  <url-pattern>*.ftl</url-pattern>
</servlet-mapping> 
</web-app>

3.在webapp创建一个ftl文件，运行后可以直接在浏览器上输入它的路径

<#list 1..10 as i>
<#if (i_index+1)%2==0>
	<font color=red>${i}</font><br/>
	<#else>
	<font color=green>${i}</font><br/>
</#if>	
</#list>

4.应用maven ，在数据库创建一张表用来存储，以新闻发布为例，新闻的标题，内容，HTML路径，发布时间

4.创建新闻后端上传项目，在pom.xml中配置架包

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>cn</groupId>
  <artifactId>news</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>
  <dependencies>
  	<!-- 数据库的架包 -->
  	<dependency>
  		<groupId>mysql</groupId>
  		<artifactId>mysql-connector-java</artifactId>
  		<version>5.1.26</version>
  	</dependency>
  	<!-- freemarker的架包 -->
  <dependency>
  	<groupId>org.freemarker</groupId>
	<artifactId>freemarker</artifactId>
 	 <version>2.3.23</version>
  </dependency>
 
  </dependencies>
  <!-- 设置字符集 -->
  <build>
  <plugins>
  	<plugin>
  		<groupId>org.codehaus.mojo</groupId>
  			<artifactId>tomcat-maven-plugin</artifactId>
  			<version>1.1</version>
  			<configuration>
  			<uriEncoding>UTF-8</uriEncoding>
  		</configuration>
  	</plugin>
  </plugins>
  </build>
</project>

5.在src/main/resources中配置数据的资源文件 .properties

url=jdbc:mysql://localhost:3306/news
drclass=com.mysql.jdbc.Driver
userName=root
password=123456

6.配置调用数据源的方法

package model;

import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;



public class Dbuit {
	static Properties p = new Properties();
	static{
		
		InputStream is = Dbuit.class.getResourceAsStream("/jdbc.properties");
		try {
			p.load(is);
		} catch (IOException e) {
			
			e.printStackTrace();
		}
	}
/*获取链接
 * @return
 * 
 */
	public static Connection getConnection() throws Exception{
		String url=p.getProperty("url");
		String drclass=p.getProperty("drclass");
		String userName=p.getProperty("userName");
		String password=p.getProperty("password");
		Class.forName(drclass);
		//登录成功
		Connection conn = DriverManager.getConnection(url,userName,password);
		
		return conn;
	}
	//执行sql语句
	public static int execute(String sql) throws Exception{
		//连接数据库
		Connection con=getConnection();
		//预编译SQL语句
		PreparedStatement pst=con.prepareStatement(sql);
		//执行SQL语句
		int i=pst.executeUpdate();
		con.close();
		pst.close();
		return i;
		
	}
	//查询
	public static List<Map> query(String sql) throws Exception{
		
		//连接数据库
		Connection con=getConnection();
		//预编译SQL语句
		PreparedStatement pst=con.prepareStatement(sql);
		//执行SQL语句
		ResultSet rs=pst.executeQuery();
		//获取列名
		ResultSetMetaData remd =rs.getMetaData();
		List list=new ArrayList();
		//获取列的个数
		int columnCount =remd.getColumnCount();
	
		while(rs.next()){
			Map map= new HashMap();
			for(int i=1;i<=columnCount;i++){
				//获取列名
				String colName=remd.getColumnName(i);
				//获取列值
				String colValue=rs.getString(i);
				map.put(colName, colValue);
			}
			list.add(map);
		}
		con.close();
		pst.close();
		rs.close();
		return list;
		
	}
	
	
}

7.创建新闻上传，查询的方法

package model;

import java.util.List;
import java.util.Map;

public class Mynews {
	//发布新闻
	public void inserNews(String title,String content,String newspath,String createtime) throws Exception{
		String sql="insert into mynews(title,content,htmlpath,createtime)values('"+title+"','"+content+"','"+newspath+"','"+createtime+"')";
		Dbuit.execute(sql);
	}
	//查询新闻
	public List<Map> queryNews() throws Exception{
		String sql="select * from mynews";
		 return Dbuit.query(sql);
	
	}
	
}

8.创建上传新闻的页面

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body align="center">
	<h1><font color=blue>新闻发布</font></h1>
	<form action="News" method="post">
	
	标题:<input type="text" name="title"/><br/>
	内容:<textarea rows="20" cols="100" name="content"></textarea><br/>
	<input type="submit">
	</form>
</body>
</html>

9.controller层servlet的调用

package controller;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import freemarker.template.Configuration;
import freemarker.template.DefaultObjectWrapper;
import freemarker.template.Template;
import model.Mynews;

/**
 * Servlet implementation class News
 */
public class News extends HttpServlet {
	private static final long serialVersionUID = 1L;

    /**
     * Default constructor. 
     */
    public News() {
        // TODO Auto-generated constructor stub
    }
    //调用插入，查询的方法
    Mynews my= new Mynews();
    //设计时间格式
    SimpleDateFormat sdf= new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    //生成静态HTML存储的位置
    public static final String HTML_DIR="E:\\html";
	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//设置字符集
		response.setContentType("text/html;charset=UTF-8");
		request.setCharacterEncoding("UTF-8");
		//获取新闻的标题
		String title=request.getParameter("title");
		//获取新闻的内容
		String content=request.getParameter("content");
		//获取时间
		Date date= new Date();
		String dates=sdf.format(date);
		//获取唯一的UUID
		String uuid=UUID.randomUUID().toString();
		try {
		
			//生成HTML
		Configuration config=new Configuration(Configuration.VERSION_2_3_23);  
			//模板文件的位置
        config.setDirectoryForTemplateLoading(new File("src/main/resources"));  
        config.setObjectWrapper(new DefaultObjectWrapper(Configuration.VERSION_2_3_23));
        //把值注入HTML
        Map root = new HashMap();
        root.put("title", title);
        root.put("content", content);
        root.put("createtime", dates);
        ////加载模板文件  -- 实例化模板对象
        Template temp =config.getTemplate("news.ftl");
       //文件的保存路径
		String sa=HTML_DIR+"/"+(uuid)+".html";
        Writer out =new OutputStreamWriter(new FileOutputStream(sa));  
        //文件的输出
        temp.process(root, out);  
        out.flush(); 
        out.close();
        //新闻上传到数据库
		my.inserNews(title, content, (uuid) + ".html", dates);
		response.getWriter().println("发布成功...");
		} catch (Exception e) {
			
			e.printStackTrace();
		}
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		
		doGet(request, response);
	}

}

10.新闻的模板

<div style="text-align:center;"><h1><font color=red>${title}</font><br/></h1></div>
  ${createtime}<br/>
  ${content}

11.创建前端freemarker项目，在本地pom.xml中配置依赖的架包

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>cn</groupId>
  <artifactId>new</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>
  <dependencies>
  	<!-- 配置数据库的架包 -->
  	<dependency>
  		<groupId>mysql</groupId>
  		<artifactId>mysql-connector-java</artifactId>
  		<version>5.1.26</version>
  	</dependency>
  	<!-- 配置freemarker的架包 -->
  <dependency>
	  <groupId>org.freemarker</groupId>
	  <artifactId>freemarker</artifactId>
	  <version>2.3.23</version>
  </dependency>
  <!-- 配置commons-io的架包 -->
  <dependency>
 	 <groupId>org.apache.commons</groupId>
 	 <artifactId>commons-io</artifactId>
 	 <version>1.3.2</version>
</dependency>
  </dependencies>
  <!-- 设置字符集 -->
  <build>
  <plugins>
  	<plugin>
  		<groupId>org.codehaus.mojo</groupId>
  		<artifactId>tomcat-maven-plugin</artifactId>
  		<version>1.1</version>
  		<configuration>
  		<uriEncoding>UTF-8</uriEncoding>
  		</configuration>
  	</plugin>
  </plugins>
  </build>
</project>

12.配置连接数据库的四要素，在src/main/resources中创建 .properties文件

url=jdbc:mysql://localhost:3306/news
drclass=com.mysql.jdbc.Driver
userName=root
password=123456

13.调用封装jdbc的方法类

package model;

import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;



public class Dbuit {
	static Properties p = new Properties();
	static{
		
		InputStream is = Dbuit.class.getResourceAsStream("/jdbc.properties");
		try {
			p.load(is);
		} catch (IOException e) {
			
			e.printStackTrace();
		}
	}
/*获取链接
 * @return
 * 
 */
	public static Connection getConnection() throws Exception{
		String url=p.getProperty("url");
		String drclass=p.getProperty("drclass");
		String userName=p.getProperty("userName");
		String password=p.getProperty("password");
		Class.forName(drclass);
		//登录成功
		Connection conn = DriverManager.getConnection(url,userName,password);
		
		return conn;
	}
	
	//执行sql
	public static int execute(String sql) throws Exception{
		//连接数据库
		Connection con=getConnection();
		//预编译SQL语句
		PreparedStatement pst=con.prepareStatement(sql);
		//执行SQL语句
		int i=pst.executeUpdate();
		con.close();
		pst.close();
		return i;
		
	}
	//查询
	public static List<Map> query(String sql) throws Exception{
		
		//连接数据库
		Connection con=getConnection();
		//预编译SQL语句
		PreparedStatement pst=con.prepareStatement(sql);
		//执行SQL语句
		ResultSet rs=pst.executeQuery();
		//获取列名
		ResultSetMetaData remd =rs.getMetaData();
		List list=new ArrayList();
		//获取列的个数
		int columnCount =remd.getColumnCount();
	
		while(rs.next()){
			Map map= new HashMap();
			for(int i=1;i<=columnCount;i++){
				//获取列名
				String colName=remd.getColumnName(i);
				//获取列值
				String colValue=rs.getString(i);
				map.put(colName, colValue);
			}
			list.add(map);
		}
		con.close();
		pst.close();
		rs.close();
		return list;
		
	}
	
	
}

14.创建查询新闻的方法

package model;

import java.util.List;
import java.util.Map;

public class Mynews {
	
	//查询
	public List<Map> queryNews() throws Exception{
		String sql="select * from mynews";
		 return Dbuit.query(sql);
	
	}
	
}

15.刷新新闻页面

package main;

import java.util.Timer;

public class Index {
	public static void main(String[] args) {
		Timer ti= new Timer();
		//new执行任务，执行时间，执行第一次之后多少时间之后执行下一次
		ti.schedule(new MyTimerTask(), 1000,5000);
	}
}

16.生成前端模板

<#list List as new>
<#-- 首页显示新闻的连接与标题-->
<a href="new?path=${new.htmlpath}">${new.title}</a><br/>
</#list>

17.生成前端首页

package main;

import java.io.File;
import java.io.FileOutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.TimerTask;

import freemarker.template.Configuration;
import freemarker.template.DefaultObjectWrapper;
import freemarker.template.Template;
import model.Mynews;

public class MyTimerTask extends TimerTask{
	//调用查询的方法
	Mynews my= new Mynews();

	public void run(){
		try {
			// 生成html
			Configuration cfg = new Configuration(Configuration.VERSION_2_3_23);
			//模板文件的位置
			cfg.setDirectoryForTemplateLoading(new File("src/main/resources"));
			cfg.setObjectWrapper(new DefaultObjectWrapper(Configuration.VERSION_2_3_23));
			//获取所有的新闻
			List<Map> result=my.queryNews();
			Map root = new HashMap();
			root.put("List", result);
			  //加载模板文件  -- 实例化模板对象
			Template temp = cfg.getTemplate("index.ftl");
			//生成首页页面的位置
			String saveFile =  "src/main/webapp/index.html";
			//写入内容
			Writer out = new OutputStreamWriter(new FileOutputStream(saveFile));
			temp.process(root, out);
			out.flush();
			out.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}

18. 读取新闻的内容

package main;

import java.io.File;
import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.io.FileUtils;

/**
 * Servlet implementation class NewServler
 */
public class NewServler extends HttpServlet {
	private static final long serialVersionUID = 1L;

    /**
     * Default constructor. 
     */
    public NewServler() {
        // TODO Auto-generated constructor stub
    }
    //新闻存储的位置
    public static final String HTML_DIR = "E:\\html\\";
	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//获取模板传过来的连接路径
		String path=request.getParameter("path");
		//完整的文件存储路径
		String abs=HTML_DIR+path;
		//读取存储的新闻内容
		byte[] bt=FileUtils.readFileToByteArray(new File(abs));
		//输出到首页连接
		response.getOutputStream().write(bt);
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}

19.启动后台发布新闻项目，在运行前台新闻首页