What is the easiest way to render a freemarker object as JSON?

Question

I have a data structure in freemarker which I would like to render as JSON notation in the output, similar to Javascript's JSON.stringify, is there something in freemarker such as object?json or any other simple way?

Answer 1

We wrote a simple pseudo DataLoader for FreeMarker that returns an "JSON" object that provides the methodes stringify() and parse():

package de.teambits.server.fmpp;

import flexjson.JSONDeserializer;
import flexjson.JSONSerializer;
import fmpp.Engine;
import fmpp.tdd.DataLoader;

import java.util.List;

/**
 * Returns a JSON object that offers parse() and stringify() methods for use in fmpp
 */
public class JSONFactory implements DataLoader {

    @Override
    public Object load(Engine e, List args) throws Exception {
        return new JSON();
    }

    public static class JSON {
        public String stringify(Object object) {
            return new JSONSerializer().deepSerialize(object);
        }

        public Object parse(String jsonString) {
            return new JSONDeserializer().deserialize(jsonString);
        }
    }
}

So, if you add to your Freemarker / fmpp config this JSON object:

data: {
    JSON: de.teambits.server.fmpp.JSONFactory()
}

You can simple call ${ JSON.stringify(object) } or ${ JSON.parse("json-string") }