Terry.Li-彬

1、java應用程序中
    我用maven導入FreeMarker的jar包
   
    <dependency>
      <groupId>freemarker</groupId>
      <artifactId>freemarker</artifactId>
      <version>2.3.8</version>
    </dependency>

    package com.test;

import java.io.IOException;
import java.io.StringWriter;
import java.util.HashMap;
import java.util.Map;

import freemarker.cache.ClassTemplateLoader;
import freemarker.template.Configuration;
import freemarker.template.DefaultObjectWrapper;
import freemarker.template.Template;
import freemarker.template.TemplateException;

public class Test {

    /** *//**
     * @param args
     */
    public static void main(String[] args) {
        Configuration configuration = new Configuration();
        configuration.setObjectWrapper(new DefaultObjectWrapper());
        configuration.setTemplateLoader(new ClassTemplateLoader(Test.class, "/com/test"));
        try {
            Template template = configuration.getTemplate("temp.ftl");
            StringWriter writer = new StringWriter();
            Map<String, Object> context = new HashMap<String, Object>();
           
            context.put("message", "我的第一個FreeMarker程序");
           
            template.process(context, writer);
            System.out.println(writer.toString());
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (TemplateException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

}

這里是用java應用程序，需要加入下面兩句（設置模板文件載入）：
方法一：
  configuration.setObjectWrapper(new DefaultObjectWrapper());
  configuration.setTemplateLoader(new ClassTemplateLoader(Test.class, "/com/test"));

其中"/com/test" 是模板文件所在的文件夾，前面的“/”必須，這里我的模板文件和當前java類在同一路徑下，則這樣寫，如果你的模板文件在src跟目錄下，這里只需要寫“/”就可以了

context.put("message", "我的第一個FreeMarker程序");
是模板文件中用到的變量，map中的變量可以是javabean，也可以是對象

方法二：
configuration.setServletContextForTemplateLoading(getServletContext(), "WEB-INF/templates");
這里主要針對Servlet的時候，當然在Servlet中也可以用方法一提到的寫法
package com.newegg.lab.freemarker.servlet;

import java.io.IOException;
import java.io.StringWriter;
import java.io.Writer;
import java.util.HashMap;
import java.util.Map;

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

import freemarker.cache.ClassTemplateLoader;
import freemarker.template.Configuration;
import freemarker.template.DefaultObjectWrapper;
import freemarker.template.Template;
import freemarker.template.TemplateException;

/** *//**
 * Servlet implementation class for Servlet: FreemarkerServlet
 *
 */
public class FreemarkerServlet extends javax.servlet.http.HttpServlet implements
        javax.servlet.Servlet {

    private Configuration configuration;

    private Template template;
    /**//*
     * (non-Java-doc)
     *
     * @see javax.servlet.http.HttpServlet#HttpServlet()
     */
    public FreemarkerServlet() {
        super();
    }

    @Override
    public void destroy() {
        // TODO Auto-generated method stub
        configuration = null;
    }

    @Override
    public void init() throws ServletException {
        // TODO Auto-generated method stub
        configuration = new Configuration();
        configuration.setServletContextForTemplateLoading(getServletContext(), "WEB-INF/templates");
//        configuration.setObjectWrapper(new DefaultObjectWrapper());
//        configuration.setTemplateLoader(new ClassTemplateLoader(FreemarkerServlet.class, "/"));
    }

    /**//*
     * (non-Java-doc)
     *
     * @see javax.servlet.http.HttpServlet#doGet(HttpServletRequest request,
     *      HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        this.doPost(request, response);
    }

    /**//*
     * (non-Java-doc)
     *
     * @see javax.servlet.http.HttpServlet#doPost(HttpServletRequest request,
     *      HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        Map root = new HashMap();
        root.put("message", "Hello World!的的的的");

        // Get the templat object
        Template t = configuration.getTemplate("test.ftl");

        // Prepare the HTTP response:
        // - Use the charset of template for the output
        // - Use text/html MIME-type
        response.setContentType("text/html; charset=" + t.getEncoding());
        Writer out = response.getWriter();

        // Merge the data-model and the template
        try {
            t.process(root, out);

            StringWriter stringWriter = new StringWriter();
            t.process(root, stringWriter);
            System.out.println(stringWriter.toString());
        } catch (TemplateException e) {
            throw new ServletException(
                    "Error while processing FreeMarker template", e);
        }
    }
}

模板文件中需要使用 ${}將java類中在Map對象中聲明的變量包圍起來就可以了

例如模板文件：
<pre>
//描述信息是 : ${message}
</pre>

則得到的結果是：
<pre>
//描述信息是 : Hello World!的的的的
</pre>