Velocity Apache inject value otomatis

Description

Velocity Apache adalah template engine yang berguna untuk meng inject file atau data seperti XML, HTML, SQL, dll

Maven

<dependency>
    <groupId>org.apache.velocity</groupId>
    <artifactId>velocity</artifactId>
    <version>1.7</version>
</dependency>
<dependency>
    <groupId>org.apache.velocity</groupId>
    <artifactId>velocity-tools</artifactId>
    <version>2.0</version>
</dependency>

Java Class

public interface TemplateEngine {
    String generate(String template, Map<String, Object> params);
}

public class VelocityTemplateEngine implements TemplateEngine{
    @Override
    public String generate(String template, Map<String, Object> params) {
        try {
            if(params == null) params = new HashMap<>();

            RuntimeServices velocityService = RuntimeSingleton.getRuntimeServices();
            Template velocityTemplate = new Template();
            velocityTemplate.setData(velocityService.parse(new StringReader(template), String.valueOf(velocityTemplate)));
            velocityTemplate.setRuntimeServices(velocityService);
            VelocityContext velocityContext = new VelocityContext();
            params.forEach(velocityContext::put);
            StringWriter writer = new StringWriter();
            velocityTemplate.initDocument();
            velocityTemplate.merge(velocityContext, writer);
            String result = writer.toString();
            writer.close();
            writer.flush();

            return result;
        } catch (ParseException | IOException e) {
            throw new IllegalStateException();
        }
    }
}

How To Use

public class Main {
    public static void main(String[] args) {
        TemplateEngine templateEngine = new VelocityTemplateEngine();
        String template = "Hallo, $name ! $say";
        Map<String, Object> map = new HashMap<>();
        map.put("name", "Petrik");
        map.put("say", "Apa Kabar?");
        System.out.println(templateEngine.generate(template, map));
    }
}