Unable to find velocity template resources

问题

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

回答1:

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

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:

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.

回答2:

I put my .vm under the src/main/resources/templates, then the code is :

Properties p = new Properties();
p.setProperty("resource.loader", "class");
p.setProperty("class.resource.loader.class", "org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader");
Velocity.init( p );       
VelocityContext context = new VelocityContext();           
Template template = Velocity.getTemplate("templates/my.vm");

this works in web project.

In eclipse Velocity.getTemplate("my.vm") works since velocity will look for the .vm file in src/main/resources/ or src/main/resources/templates, but in web project, we have to use Velocity.getTemplate("templates/my.vm");

回答3:

You can just use it like this:

Template t = ve.getTemplate("./src/main/resources/templates/email_html_new.vm");

It works.

回答4:

I faced the similar problem with intellij IDEA. you can use this

 VelocityEngine ve = new VelocityEngine();
    Properties props = new Properties();
    props.put("file.resource.loader.path", "/Users/Projects/Comparator/src/main/resources/");
    ve.init(props);

    Template t = ve.getTemplate("helloworld.vm");
    VelocityContext context = new VelocityContext();

回答5:

Make sure you have a properly configured resource loader. See Velocity documentation for help selecting and configuring a resource loader: http://velocity.apache.org/engine/releases/velocity-1.7/developer-guide.html#resourceloaders

回答6:

you can try to add these code:

VelocityEngine ve = new VelocityEngine();
String vmPath = request.getSession().getServletContext().getRealPath("${your dir}");
Properties p = new Properties();
p.setProperty("file.resource.loader.path", vmPath+"//");
ve.init(p);

I do this, and pass!

回答7:

VelocityEngine velocityEngin = new VelocityEngine();
velocityEngin.setProperty(RuntimeConstants.RESOURCE_LOADER, "classpath");
velocityEngin.setProperty("classpath.resource.loader.class", ClasspathResourceLoader.class.getName());

velocityEngin.init();

Template template = velocityEngin.getTemplate("nameOfTheTemplateFile.vtl");

you could use the above code to set the properties for velocity template. You can then give the name of the tempalte file when initializing the Template and it will find if it exists in the classpath.

All the above classes come from package org.apache.velocity*

回答8:

While using embedded jetty the property webapp.resource.loader.path should starts with slash:

webapp.resource.loader.path=/templates

otherwise templates will not be found in ../webapp/templates

回答9:

You can also put your templates folder under src/main/resources instead of src/main/java. Works for me and it's a preferable location since templates are not java source.

回答10:

I faced a similar issue. I was copying the velocity engine mail templates in wrong folder. Since JavaMailSender and VelocityEngine are declared as resources under MailService, its required to add the templates under resource folder declared for the project.

I made the changes and it worked. Put the templates as

src/main/resources/templates/<package>/sampleMail.vm

回答11:

I have put this working code snippet for future references. The code sample was written with Apache velocity version 1.7 with embedded Jetty.

Velocity template path is located at the resource folder email_templates subfolder.

Code Snippet in Java (Snippets are worked both running on eclipse and inside a Jar)

    ...
    templateName = "/email_templates/byoa.tpl.vm"
    VelocityEngine ve = new VelocityEngine();
    ve.setProperty(RuntimeConstants.RESOURCE_LOADER, "classpath");
    ve.setProperty("classpath.resource.loader.class", ClasspathResourceLoader.class.getName());
    ve.init();
    Template t = ve.getTemplate(this.templateName);
    VelocityContext velocityContext = new VelocityContext();
    velocityContext.put("","") // put your template values here
    StringWriter writer = new StringWriter();
    t.merge(this.velocityContext, writer);

System.out.println(writer.toString()); // print the updated template as string

For OSGI plugging code snippets.

final String TEMPLATE = "resources/template.vm // located in the resource folder
Thread current = Thread.currentThread();
       ClassLoader oldLoader = current.getContextClassLoader();
       try {
          current.setContextClassLoader(TemplateHelper.class.getClassLoader()); // TemplateHelper is a class inside your jar file
          Properties p = new Properties();
          p.setProperty("resource.loader", "class");
          p.setProperty("class.resource.loader.class", "org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader");
          Velocity.init( p );       
          VelocityEngine ve = new VelocityEngine();
          Template template = Velocity.getTemplate( TEMPLATE );
          VelocityContext context = new VelocityContext();
          context.put("tc", obj);
          StringWriter writer = new StringWriter();
          template.merge( context, writer );
        return writer.toString() ;  
       }  catch(Exception e){
          e.printStackTrace();
       } finally {
          current.setContextClassLoader(oldLoader);
       }

回答12:

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:

来源：https://stackoverflow.com/questions/9051413/unable-to-find-velocity-template-resources

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