Converting Java Object to Json using Marshaller?

up vote4down votefavorite	Its quite easy to convert a java object to XML by using Marshaller. But I need to convert a java object to JSON by using marshaller alone. I know its good to use gson or Xstream like things., but I need to do using Marshaller.How to achieve it? Thanks in advance. java json java-ee jaxb marshalling share|improve this question asked Mar 12 at 9:21 Tom 125317

2 Answers

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Note: I'm the EclipseLink JAXB (MOXy) lead and a member of the JAXB (JSR-222) expert group, Below is how this can be done if you are using MOXy as your JAXB provider. http://blog.bdoughan.com/2011/08/json-binding-with-eclipselink-moxy.html JAVA MODEL Customer import java.util.*; import javax.xml.bind.annotation.*; @XmlRootElement(namespace="http://www.example.com") @XmlType(namespace="http://www.example.com") @XmlAccessorType(XmlAccessType.FIELD) public class Customer { @XmlAttribute private int id; @XmlElement(namespace="http://www.example.com") private String firstName; @XmlElement(namespace="http://www.example.com", nillable=true) private String lastName; @XmlElement(namespace="http://www.example.com") private List<PhoneNumber> phoneNumbers = new ArrayList<PhoneNumber>(); } PhoneNumber import javax.xml.bind.annotation.*; @XmlAccessorType(XmlAccessType.FIELD) public class PhoneNumber { @XmlAttribute private String type; @XmlValue private String number; } jaxb.properties To specify MOXy as your JAXB provider you need to include a file called jaxb.properties in the same package as your domain model with the following entry (see:http://blog.bdoughan.com/2011/05/specifying-eclipselink-moxy-as-your.html) javax.xml.bind.context.factory=org.eclipse.persistence.jaxb.JAXBContextFactory DEMO CODE input.xml xml version="1.0" encoding="UTF-8"?> xmlns:ns0="http://www.example.com" id="123"> Jane

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:nil="true"/> type="work">555-1111

Demo

In the demo code below we will use the same JAXB metadata to convert an XML document to Java objects, and then convert those objects back to JSON. With MOXy you can specify JSON output by setting a property on the Marshaller.

import java.io.File;
import javax.xml.bind.*;
import org.eclipse.persistence.jaxb.MarshallerProperties;

public class Demo {

    public static void main(String[] args) throws Exception {
        JAXBContext jc = JAXBContext.newInstance(Customer.class);

        Unmarshaller unmarshaller = jc.createUnmarshaller();
        File xml = new File("src/forum15357366/input.xml");
        Customer customer = (Customer) unmarshaller.unmarshal(xml)
                ;
        Marshaller marshaller = jc.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        marshaller.setProperty(MarshallerProperties.MEDIA_TYPE, "application/json");
        marshaller.setProperty(MarshallerProperties.JSON_INCLUDE_ROOT, false);
        marshaller.marshal(customer, System.out);
    }

}

JSON Output

Below is the JSON output. Note how there are no indicators corresponding to namespaces or XML attributes. Also note the collection of size one was correctly represented as a JSON array (a problem with some other approaches).

{
   "id" : 123,
   "firstName" : "Jane",
   "lastName" : null,
   "phoneNumbers" : [ {
      "type" : "work",
      "value" : "555-1111"
   } ]
}

share|improve this answer

answered Mar 12 at 11:03 Blaise Doughan 59.8k648102

	@BDoughan : Yes I have seen this in your blog too. But I am getting ClassNotFound Exception on JAXBContextFactory.I have included the jaxb.properties and I put a dependency in pom.xml too. kindly guide me for the correct dependency for that class –  Tom Mar 12 at 11:15
	@user1933756 - Here is a pom.xml from an example that I have hosted on GitHub that you can use as a guide: github.com/bdoughan/blog20110819/blob/master/pom.xml –  Blaise Doughan Mar 12 at 11:27
1	Thanks a ton Doughan :) works great!!! –  Tom Mar 12 at 11:56