Unable to find velocity template resources

Just a simple velocity standalone app based on maven structure. Here is the code snippet written in Scala to render the template helloworld.vm in ${basedir}/src/main/resources folder:

com.ggd543.velocitydemo

import org.apache.velocity.app.VelocityEngine
import org.apache.velocity.VelocityContext
import java.io.StringWriter

/**
 * @author ${user.name}
 */
object App {

  def main(args: Array[String]) {
    //First , get and initialize an engine
    val ve = new VelocityEngine();
    ve.init();

    //Second, get the template
    val resUrl = getClass.getResource("/helloworld.vm")
    val t = ve.getTemplate("helloworld.vm");   // not work 
//    val t = ve.getTemplate("/helloworld.vm");  // not work
//    val t = ve.getTemplate(resUrl.toString);  // not work yet
    //Third, create a context and add data
    val context = new VelocityContext();
    context.put("name", "Archer")
    context.put("site", "http://www.baidu.com")
    //Finally , render the template into a StringWriter
    val sw = new StringWriter
    t.merge(context, sw)
    println(sw.toString);
  }

}

when to compile and run the program, I got the following error:

2012-1-29 14:03:59 org.apache.velocity.runtime.log.JdkLogChute log
严重: ResourceManager : unable to find resource '/helloworld.vm' in any resource loader.
Exception in thread "main" org.apache.velocity.exception.ResourceNotFoundException: Unable to find resource '/helloworld.vm'
    at org.apache.velocity.runtime.resource.ResourceManagerImpl.loadResource(ResourceManagerImpl.java:474)
    at org.apache.velocity.runtime.resource.ResourceManagerImpl.getResource(ResourceManagerImpl.java:352)
    at org.apache.velocity.runtime.RuntimeInstance.getTemplate(RuntimeInstance.java:1533)
    at org.apache.velocity.runtime.RuntimeInstance.getTemplate(RuntimeInstance.java:1514)
    at org.apache.velocity.app.VelocityEngine.getTemplate(VelocityEngine.java:373)
    at com.ggd543.