自己写的一个工具类: VelocityUtils

velocity1.7小例子 http://www.cnblogs.com/jston/archive/2013/02/19/2916999.html

<dependency>
            <groupId>velocity</groupId>
            <artifactId>velocity</artifactId>
            <version>1.4</version>
        </dependency>

package com.util;

import org.apache.velocity.Template;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.Velocity;
import org.apache.velocity.app.VelocityEngine;

import java.io.InputStream;
import java.io.Reader;
import java.io.StringWriter;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Properties;

/**
 * 模板处理工具类，现在只支持类路径方式，不支持jar,绝对路径等方式。
 * 
 * @author pandy
 * 
 */
@SuppressWarnings("rawtypes")
public class VelocityUtils {

	private final static String DEFAULT_TEMPLATE_PATH = "";
	private final static String DEFAULT_LOG_TAG = "mystring";
	private static VelocityEngine engine;

	/**
	 * 做初始化信息
	 */
	static {
		Properties p = new Properties();
		// 设置输入输出编码类型。和这次说的解决的问题无关
		p.setProperty(Velocity.INPUT_ENCODING, "UTF-8");
		p.setProperty(Velocity.OUTPUT_ENCODING, "UTF-8");
		
		p.setProperty("userdirective", "org.apache.velocity.tools.generic.directive.Ifnull");
		// 这里加载类路径里的模板而不是文件系统路径里的模板
		p.setProperty("resource.loader", "class");
		p.setProperty("class.resource.loader.class","org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader");

		engine = new VelocityEngine();
		try {
			engine.init(p);
			 Velocity.init();
		} catch (Exception e) {
			e.printStackTrace();
			engine = null;
		}
	}

	/**
	 * 参数转换：Pap->VelocityContext
	 * 
	 * @param paramters
	 * @return
	 */
	private static VelocityContext parseMapToVelocityContext(Map paramters) {
		VelocityContext context = new VelocityContext();
		if (paramters != null && !paramters.isEmpty()) {
			Iterator it = paramters.keySet().iterator();
			while (it.hasNext()) {
				Object key = it.next();
				Object value = paramters.get(key);
				context.put(key.toString(), value);
			}
		}
		return context;
	}

	/**
	 * 读取模板文件
	 * 
	 * @param templateName
	 * @param path
	 * @return
	 */
	private static Template getTemplate(String templateName, String path) {
		Template template = null;
		try {
			template = engine.getTemplate(path + templateName);
		} catch (Exception e) {
			// TODO 自动生成的 catch 块
			e.printStackTrace();
		}
		return template;
	}

	/**
	 * 
	 * @param templateName
	 * @return 模板的html字符串
	 */
	public static String merge(String templateName) {
		return merge(templateName, null, null, null);
	}

	/**
	 * 
	 * @param templateName
	 * @param path
	 * @return
	 */
	public static String merge(String templateName, String path) {
		return merge(templateName, path, null, null);
	}

	/**
	 * 这个方法要自动转换Map类型，变成VelocityContext类型
	 * 
	 * @param templateName
	 * @param paramters
	 * @return 模板的html字符串
	 */
	public static String merge(String templateName, Map paramters) {
		return merge(templateName, DEFAULT_TEMPLATE_PATH,
				parseMapToVelocityContext(paramters), null);
	}

	/**
	 * 
	 * @param templateName
	 * @param path
	 * @param paramters
	 * @return
	 */
	public static String merge(String templateName, String path, Map paramters) {
		return merge(templateName, path, parseMapToVelocityContext(paramters), null);
	}

	/**
	 * 
	 * @param templateName
	 * @param context
	 * @return 模板的html字符串
	 */
	public static String merge(String templateName, String path,
			VelocityContext context) {
		return merge(templateName, path, context, null);
	}

	/**
	 * 
	 * @param templateName
	 * @param context
	 * @return
	 */
	public static String merge(String templateName, VelocityContext context) {
		return merge(templateName, DEFAULT_TEMPLATE_PATH, context, null);
	}

	/**
	 * 
	 * @param templateName
	 * @param context
	 * @param writer
	 * @return 模板的html字符串
	 */
	public static String merge(String templateName, VelocityContext context,
			StringWriter writer) {
		return merge(templateName, DEFAULT_TEMPLATE_PATH, context, writer);
	}

	/**
	 * 最终执行方法
	 * 
	 * @param templateName
	 * @param path
	 * @param context
	 * @param writer
	 * @return 模板的html字符串
	 */
	public static String merge(String templateName, String path,
			VelocityContext context, StringWriter writer) {
		Template template = getTemplate(templateName, path);
		if (writer == null) {
			writer = new StringWriter();
		}

		try {
			template.merge(context, writer);
		} catch (Exception e) {
			e.printStackTrace();
            return null;
		}
		/* show the World */
		return writer.toString();
	}

	public static String mergeWithStr(Map paramters, String templateStr) {
		StringWriter writer = new StringWriter();
		return mergeWithStr(parseMapToVelocityContext(paramters), writer,
				templateStr);
	}

	public static String mergeWithStr(Map paramters, StringWriter writer,
			String templateStr) {
		return mergeWithStr(parseMapToVelocityContext(paramters), writer,
				templateStr);
	}

	public static String mergeWithStr(VelocityContext context,
			StringWriter writer, String templateStr) {
		try {
			Velocity.evaluate(context, writer, DEFAULT_LOG_TAG, templateStr);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return writer.toString();
	}

	public static String mergeWithStr(Map paramters, Reader reader) {
		StringWriter writer = new StringWriter();
		return mergeWithStr(parseMapToVelocityContext(paramters), writer,
				reader);
	}

	public static String mergeWithStr(Map paramters, StringWriter writer,
			Reader reader) {
		return mergeWithStr(parseMapToVelocityContext(paramters), writer,
				reader);
	}

	public static String mergeWithStr(VelocityContext context,
			StringWriter writer, Reader reader) {
		try {
			Velocity.evaluate(context, writer, DEFAULT_LOG_TAG, reader);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return writer.toString();
	}

	@Deprecated
	public static String mergeWithStr(Map paramters, InputStream instream) {
		StringWriter writer = new StringWriter();
		return mergeWithStr(parseMapToVelocityContext(paramters), writer,
				instream);
	}

	@Deprecated
	public static String mergeWithStr(Map paramters, StringWriter writer,
			InputStream instream) {
		return mergeWithStr(parseMapToVelocityContext(paramters), writer,
				instream);
	}

	@Deprecated
	public static String mergeWithStr(VelocityContext context,
			StringWriter writer, InputStream instream) {
		try {
			Velocity.evaluate(context, writer, DEFAULT_LOG_TAG, instream);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return writer.toString();
	}

	@SuppressWarnings("unchecked")
	public static void main(String[] args) {
		Map paramters = new HashMap();
		paramters.put("name", "Pandy");
		paramters.put("site", "http://zhuhaironghui.oicp.net");
		String str = merge("hello.vm", "com/rh/core/menu/templates/", paramters);
		System.out.println(str);
		
		System.out.println(mergeWithStr(paramters, "Hello $name!  Welcome to $site world!"));
	}

}

模板:com/templates/hello.vm
Hello $name!  Welcome to $site world!

调用

import com.util.VelocityUtils;

import java.util.HashMap;
import java.util.Map;

/**
 * Created by pandy on 14-8-13.
 */
public class ToolMain {

    public static void main(String[] args){
        Map<String, Object> context = new HashMap<String, Object>();
        context.put("name","Pandy");
        context.put("site","www.pandy8.com");
        String gridConfigStr = VelocityUtils.merge("com/templates/hello.vm", context);
        System.out.println(gridConfigStr);
    }
}

输出:
Hello Pandy!  Welcome to www.pandy8.com world!