Loading velocity template inside a jar file

Question

I have a project where I want to load a velocity template to complete it with parameters. The whole application is packaged as a jar file. What I initially thought of doing was this:

VelocityEngine ve = new VelocityEngine();

   URL url = this.getClass().getResource("/templates/");

   File file = new File(url.getFile());

   ve = new VelocityEngine();
   ve.setProperty(RuntimeConstants.RESOURCE_LOADER, "file");
   ve.setProperty(RuntimeConstants.FILE_RESOURCE_LOADER_PATH, file.getAbsolutePath());
   ve.setProperty(RuntimeConstants.FILE_RESOURCE_LOADER_CACHE, "true");

   ve.init();

   VelocityContext context = new VelocityContext();

   if (properties != null) {
    stringfyNulls(properties);
    for (Map.Entry<String, Object> property : properties.entrySet()) {
     context.put(property.getKey(), property.getValue());
    }
   }

   final String templatePath = templateName + ".vm";
   Template template = ve.getTemplate(templatePath, "UTF-8");
   String outFileName = File.createTempFile("report", ".html").getAbsolutePath();
   BufferedWriter writer = new BufferedWriter(new FileWriter(new File(outFileName)));

   template.merge(context, writer);

   writer.flush();
   writer.close();

And this works fine when I run it in eclipse. However, once I package the program and try to run it using the command line I get an error because the file could not be found.

I imagine the problem is in this line:

ve.setProperty(RuntimeConstants.FILE_RESOURCE_LOADER_PATH, file.getAbsolutePath());

Because in a jar the absolute file does not exist, since it's inside a zip, but I couldn't yet find a better way to do it.

Anyone has any ideas?

Answer 1

If you want to use resources from classpath, you should use resource loader for classpath:

ve.setProperty(RuntimeConstants.RESOURCE_LOADER, "classpath"); 
ve.setProperty("classpath.resource.loader.class", ClasspathResourceLoader.class.getName());