freemarker 自定义标签

最近项目中要将前台的好多首页静态化，当然首选freemarker，可前台首页算下来有好十几个，这样一个一个在页面用freemarker标签不累死人。在网上找了好多资料，发现freemarker可以像jsp那样自定义标签。嘿嘿 这样就简单了将要显示的内容给他输出出来，页面控制他的样式，这不就省了不少事 

package com.f139.frame.freemarker.directive;

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

import org.nutz.dao.Dao;

import com.f139.frame.pojo.factory.Label;

import freemarker.core.Environment;
import freemarker.template.TemplateDirectiveBody;
import freemarker.template.TemplateDirectiveModel;
import freemarker.template.TemplateException;
import freemarker.template.TemplateModel;

public class LabelDirective implements TemplateDirectiveModel {

    private Dao dao;

    public LabelDirective(Dao dao) {
        this.dao = dao;
    }

    @Override
    @SuppressWarnings("unchecked")
    public void execute(Environment env, Map params, TemplateModel[] loopVars, TemplateDirectiveBody body) throws TemplateException, IOException {
        
        for (TemplateModel templateModel : loopVars) {
            templateModel.toString();
        }
        
        // 真正开始处理输出内容
        Writer out = env.getOut();

        if (body != null) {
            out.write(getContent(params));
            body.render(out);
        }
    }

    private String getContent(Map<?,?> params) {
        Integer id = Integer.parseInt(params.get("id").toString());
        if (null != id) {
            Label label = this.dao.fetch(Label.class, id);
            return label.getLabelContent();
        }
        return null;
    }
}

将自定义freemarker 标签添加到ExtendServlet 

package com.f139.frame.servlet;

import org.nutz.dao.Dao;
import org.nutz.dao.impl.NutDao;
import org.nutz.ioc.Ioc;
import org.nutz.ioc.impl.NutIoc;
import org.nutz.ioc.loader.json.JsonLoader;

import com.f139.frame.tag.RepeatDirective;

import freemarker.ext.jsp.TaglibFactory;
import freemarker.ext.servlet.FreemarkerServlet;
import freemarker.template.Configuration;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateModelException;


public class ExtendServlet extends FreemarkerServlet {

    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    private Dao dao;

    public ExtendServlet() {
        Ioc ioc = new NutIoc(new JsonLoader("com/f139/frame/ioc"));
        this.dao = ioc.get(NutDao.class, "dao");
    }

    @Override
    protected Configuration createConfiguration() {
        //添加自定义标签
        Configuration cfg = super.createConfiguration();
        cfg.setSharedVariable("label", new LabelDirective(dao));
        return cfg;
    }

}

ExtendServlet继承FreemarkerServlet[代码] 
在web.xml添加相应配置 

<servlet>
        <servlet-name>freemarker</servlet-name>
        <servlet-class>com.f139.frame.servlet.ExtendServlet</servlet-class>
        <init-param>
            <param-name>TemplatePath</param-name>
            <param-value>/</param-value>
        </init-param>
        <init-param>
            <param-name>NoCache</param-name>
            <param-value>true</param-value>
        </init-param>
        <init-param>
            <param-name>ContentType</param-name>
            <param-value>text/html;charset=UTF-8</param-value>
        </init-param>
        <init-param>
            <param-name>template_update_delay</param-name>
            <param-value>0</param-value>
        </init-param>
        <init-param>
            <param-name>default_encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
        <init-param>
            <param-name>number_format</param-name>
            <param-value>0.##########</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

[代码] 使用自己的标签 
<@label id=21> 

</@label>