freemarker提供了TemplateDirectiveModel介面，我們可以利用它來實現自定義標籤的編寫。

例子來源於freemarker中文參考手冊

如有:repeatDirective.rj

<#assign x = 1>
<@repeat count=4>
Test ${x}
<#assign x = x + 1>
</@repeat>
<@repeat count=3 hr=true>
Test
</@repeat>
<@repeat count=3; cnt>
${cnt}. Test
</@repeat>
 

Test 1
Test 2
Test 3
Test 4
Test
<hr> Test
<hr> Test
1. Test
2. Test
3. Test

定義一個RepeatDirective類，是實現TemplateDirectiveModel介面，重寫其中的execute方法。

public void execute(Environment env, Map params, TemplateModel[] loopVars, TemplateDirectiveBody body) throws TemplateException,
			IOException
 

loopVars:變數，如cnt，loopVars是一個TemplateModel型別的陣列，我們可以在程式中給它賦值。

具體操作如下:

RepeatDirective

package com.xuzengqiang.freemarker.customDirective;

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

import freemarker.core.Environment;
import freemarker.template.SimpleNumber;
import freemarker.template.TemplateBooleanModel;
import freemarker.template.TemplateDirectiveBody;
import freemarker.template.TemplateDirectiveModel;
import freemarker.template.TemplateException;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateModelException;
import freemarker.template.TemplateNumberModel;
import freemarker.template.TemplateScalarModel;

/*
 * <@repeat>
 * ...
 * <@repeat>
 */
@SuppressWarnings("all")
public class RepeatDirective implements TemplateDirectiveModel
{
	private static final String COUNT="count";
	private static final String HR="hr";
	
	@Override
	public void execute(Environment env, Map params, TemplateModel[] loopVars, TemplateDirectiveBody body) throws TemplateException, IOException
	{	
		if(body==null)
		{
			throw new TemplateModelException("null body");
		}
		else 
		{
			int count=0;
			boolean hr=false;
			Iterator iterator=params.entrySet().iterator();
			while(iterator.hasNext())
			{
				Map.Entry<String,TemplateModel> param=(Map.Entry<String, TemplateModel>)iterator.next();
				String paramName=param.getKey();
				TemplateModel paramValue=param.getValue();
				if(paramName.equals(COUNT))
				{
					count=getInt(paramName,paramValue);
					if(count<0)
					{
						throw new TemplateModelException("次數不能小於0");
					}
				}
				if(paramName.equals(HR))
				{
					hr=getBoolean(paramName,paramValue);
				}
			}
			
			Writer out=env.getOut();
			for(int i=0;i<count;i++)
			{
				if(hr && i!=0)
				{
					out.write("<hr>");
				}
				//設定了迴圈變數
				if(loopVars.length>0)
				{
					loopVars[0]=new SimpleNumber(i+1);
				}
				body.render(out);                       
			}
		}
	}

	public static int getInt(String paramName,TemplateModel paramValue) throws TemplateModelException
	{
		if(paramValue==null)
		{
			return 0;
		}
		else 
		{
			if(paramValue instanceof TemplateScalarModel)  //是字串
			{
				String value=((TemplateScalarModel)paramValue).getAsString();
				return Integer.valueOf(value);
			}
			else if(paramValue instanceof TemplateNumberModel)  //數字 
			{
				return ((TemplateNumberModel)paramValue).getAsNumber().intValue();
			}
			else 
			{
				throw new TemplateModelException("int轉換異常!");
			}
		}
	}
	
	public static boolean getBoolean(String paramName,TemplateModel paramValue) throws TemplateModelException
	{
		if(paramValue==null)
		{
			return false;
		}
		else 
		{
			if(paramValue instanceof TemplateScalarModel)  //是字串
			{
				String value=((TemplateScalarModel)paramValue).getAsString();
				return Boolean.valueOf(value);
			}
			else if(paramValue instanceof TemplateBooleanModel)  //boolean 
			{
				return ((TemplateBooleanModel)paramValue).getAsBoolean();
			}
			else 
			{
				throw new TemplateModelException("boolean轉換異常!");
			}
		}
	}
	
}

package com.xuzengqiang.freemarker;

import java.io.File;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.HashMap;
import java.util.Map;

import com.xuzengqiang.freemarker.customDirective.RepeatDirective;
import com.xuzengqiang.freemarker.framework.RepeatMethod;

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

@SuppressWarnings("all")
public class RepeatMethodTest
{

	public static void initData()
	{
		try
		{
			Configuration cfg = new Configuration();
			cfg.clearTemplateCache();  //手動清除快取
			//載入模板
			cfg.setDirectoryForTemplateLoading(new File("template"));
			cfg.setObjectWrapper(new DefaultObjectWrapper());
			Template temp=cfg.getTemplate("repeatDirective.rj");
			
			Map root=new HashMap();
			root.put("repeat", new RepeatDirective());
			Writer writer=new OutputStreamWriter(System.out); //直接在控制檯輸出
			temp.process(root, writer);
			writer.flush();
			
		} 
		catch(Exception e)
		{
			e.printStackTrace();
		}
		
	}
	
	public static void main(String[] args)
	{
		initData();
	}
}