Converting Java Object to Json using Marshaller

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"?><ns0:customer xmlns:ns0="http://www.example.com" id="123">   <ns0:firstName>Jane</ns0:firstName>   <ns0:lastName xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:nil="true"/>   <ns0:phoneNumbers type="work">555-1111</ns0:phoneNumbers></ns0:customer>

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"   } ]}

JsonMarshaller is a Java 1.5 library that allows marshalling and unmarshalling of JSON objects to and from Java objects. This project's goal is above all ease of use, transparency and static type safety.Example

If you have the following Java class:

JAVA:

@Entityclass Book {@Value  private String title;@Value  private String isbn;@Value  private Set<author> authors;}@Entityclass Author {@Value  private String firstName;@Value  private String lastName;}

and you created a new Book() and populated it with info it could marshal too:

JSON:{title:   "java", isbn:    "122333", authors: [{firstName: "Herbert", lastName: "Shield"},           {firstName: "Pascal",  lastName: "Perez"}]}