Apache Velocityでクラスパス上のテンプレートを使用

build.gradle

dependencies {
    implementation 'org.apache.velocity:velocity:1.7'
}

/src/main/resources/templates/hoge.vm

key = $key

import java.io.IOException;
import java.io.StringWriter;
import java.util.Properties;

import org.apache.velocity.Template;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.Velocity;
import org.apache.velocity.context.Context;
import org.apache.velocity.runtime.RuntimeConstants;
import org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader;

public class Main {

  public static void main(String[] args) {
    Properties p = new Properties();
    p.setProperty(RuntimeConstants.RESOURCE_LOADER, "classpath");
    p.setProperty("classpath.resource.loader.class", ClasspathResourceLoader.class.getName());
    Velocity.init(p);

    Context context = new VelocityContext();
    context.put("key", "value0001");

    Template template = new Template();
    template = Velocity.getTemplate("templates/hoge.vm", "UTF-8");

    try (StringWriter body = new StringWriter();) {
      template.merge(context, body);
      body.flush();
      System.out.println(body.toString());;
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
}