Question

To solve another problem I have moved from using Jersey to EclipseLink MOXy to generate JSON from a JAXB created object model ( created by Sun JAXB 2.1.12). One difference I’ve noticed is the formatting of the output

that Jersey outputs

{"artist-list":{"offset":0,"count":1,"artist":[{"score":"100","type":"Group","id":"4302e264-1cf0-4d1f-aca7-2a6f89e34b36","name":"Farming Incident","sort-name":"Incident, Farming","gender":"male","country":"AF","disambiguation":"the real one","ipi-list":{"ipi":["1001","1002"]},"life-span":{"begin":"1999-04","ended":"true"},"tag-list":{"tag":[{"count":5,"name":"thrash"},{"count":11,"name":"güth"}]}}]}}

but MOXy gives

"count" : "1",
   "offset" : "0",
   "artist" : [ {
      "id" : "4302e264-1cf0-4d1f-aca7-2a6f89e34b36",
      "type" : "Group",
      "score" : "100",
      "name" : "Farming Incident",
      "sort-name" : "Incident, Farming",
      "gender" : "male",
      "country" : "AF",
      "disambiguation" : "the real one",
      "ipis" : [ "1001", "1002" ],
      "life-span" : {
         "begin" : "1999-04",
         "ended" : "true"
      },
      "tags" : [ {
         "count" : "5",
         "name" : "thrash"
      }, {
         "count" : "11",
         "name" : "güth"
      } ]
   } ]
}

Moxy is much prettier 🙂
But one of the reasons to move to make our data available via Json is to reduce transmission bandwidth so is it possible to get MOXy to generate all one line, and without the extra spaces around each : ?

Answer 1

By default EclipseLink JAXB (MOXy) will marshal the JSON to one line. To get formatted output you need to set the following property on the Marshaller:

marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);

Root

package forum11450509;

public class Root {

    private String foo;
    private int bar;

    public String getFoo() {
        return foo;
    }

    public void setFoo(String foo) {
        this.foo = foo;
    }

    public int getBar() {
        return bar;
    }

    public void setBar(int bar) {
        this.bar = bar;
    }

}

jaxb.properties

javax.xml.bind.context.factory=org.eclipse.persistence.jaxb.JAXBContextFactory

Demo

The following code demonstrates how to specify formatted output:

package forum11450509;

import java.util.*;
import javax.xml.bind.*;
import org.eclipse.persistence.jaxb.JAXBContextProperties;

public class Demo {

    public static void main(String[] args) throws Exception {
        Map<String, Object> properties = new HashMap<String, Object>(2);
        properties.put(JAXBContextProperties.MEDIA_TYPE, "application/json");
        properties.put(JAXBContextProperties.JSON_INCLUDE_ROOT, false);
        JAXBContext jc = JAXBContext.newInstance(new Class[] {Root.class}, properties);

        Root root = new Root();
        root.setFoo("ABC");
        root.setBar(123);

        System.out.println("One Line:");
        Marshaller marshaller = jc.createMarshaller();
        marshaller.marshal(root, System.out);

        System.out.println("\nFormatted:");
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        marshaller.marshal(root, System.out);
    }

}

Output

Below is the output from running the demo code:

One Line
{"bar":123,"foo":"ABC"}
Formatted:
{
   "bar" : 123,
   "foo" : "ABC"
}

---

JAX-RS

The same behaviour holds for MOXyJsonProvider (see: http://blog.bdoughan.com/2012/05/moxy-as-your-jax-rs-json-provider.html).

One Line

By default when you include MOXyJsonProvider in your JAX-RS application, the output will be marshalled on one line:

package org.example;

import java.util.*;
import javax.ws.rs.core.Application;
import org.eclipse.persistence.jaxb.rs.MOXyJsonProvider;

public class CustomerApplication  extends Application {

    @Override
    public Set<Class<?>> getClasses() {
        HashSet<Class<?>> set = new HashSet<Class<?>>(2);
        set.add(MOXyJsonProvider.class);
        set.add(CustomerService.class);
        return set;
    }

}

Formatted Output

You can also configure MOXyJsonProvider to produce formatted output:

package org.example;

import java.util.*;
import javax.ws.rs.core.Application;
import org.eclipse.persistence.jaxb.rs.MOXyJsonProvider;

public class CustomerApplication  extends Application {

    @Override
    public Set<Class<?>> getClasses() {
        HashSet<Class<?>> set = new HashSet<Class<?>>(1);
        set.add(ExampleService.class);
        return set;
    }

    @Override
    public Set<Object> getSingletons() {
        MOXyJsonProvider moxyJsonProvider = new MOXyJsonProvider();
        moxyJsonProvider.setFormattedOutput(true);
    }

}