java - Unable to find velocity template resources

Question

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.velocitydemo.App$.main(App.scala:20)
    at com.ggd543.velocitydemo.App.main(App.scala)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)

Process finished with exit code 1

Answer 1

Great question - I solved my issue today as follows using Ecilpse:

1. Put your template in the same folder hierarchy as your source code (not in a separate folder hierarchy even if you include it in the build path) as below:

2. In your code simply use the following lines of code (assuming you just want the date to be passed as data):

   VelocityEngine ve = new VelocityEngine();
   ve.setProperty(RuntimeConstants.RESOURCE_LOADER, "classpath");
   ve.setProperty("classpath.resource.loader.class", ClasspathResourceLoader.class.getName());
   ve.init();
   VelocityContext context = new VelocityContext();
   context.put("date", getMyTimestampFunction());
   Template t = ve.getTemplate( "templates/email_html_new.vm" );
   StringWriter writer = new StringWriter();
   t.merge( context, writer );
   

See how first we tell VelocityEngine to look in the classpath. Without this it wouldn't know where to look.