The Java API for JSON Processing (JSR-353) is the Java standard for producing and consuming JSON which was introduced as part of Java EE 7. JSR-353 includes object (DOM like) and stream (StAX like) APIs. In this post I will demonstrate the initial JSR-353 support we have added to MOXy‘s JSON binding in EclipseLink 2.6. You can now use MOXy to marshal to:
- javax.json.JsonArrayBuilder
- javax.json.JsonObjectBuilder
And unmarshal from:
- javax.json.JsonStructure
- javax.json.JsonObject
- javax.json.JsonArray
You can try this out today using a nightly build of EclipseLink 2.6.0:
The JSR-353 reference implementation is available here:
Java Model
Below is the simple customer model that we will use for this post. Note for this example we are only using the standard JAXB (JSR-222) annotations.
Customer
package blog.jsonp.moxy;
import java.util.*;
import javax.xml.bind.annotation.*;
@XmlType(propOrder={"id", "firstName", "lastName", "phoneNumbers"})
public class Customer {
private int id;
private String firstName;
private String lastName;
private List<PhoneNumber> phoneNumbers = new ArrayList<PhoneNumber>();
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
@XmlElement(nillable=true)
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
@XmlElement
public List<PhoneNumber> getPhoneNumbers() {
return phoneNumbers;
}
}PhoneNumber
package blog.jsonp.moxy;
import javax.xml.bind.annotation.*;
@XmlAccessorType(XmlAccessType.FIELD)
public class PhoneNumber {
private String type;
private String number;
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
public String getNumber() {
return number;
}
public void setNumber(String number) {
this.number = 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: Specifying EclipseLink MOXy as your JAXB Provider)
javax.xml.bind.context.factory=org.eclipse.persistence.jaxb.JAXBContextFactory
Marshal Demo
In the demo code below we will use a combination of JSR-353 and MOXy APIs to produce JSON. JSR-353’s JsonObjectBuilder and JsonArrayBuilder are used to produces instances of JsonObject and JsonArray. We can use MOXy to marshal to these builders by wrapping them in instances of MOXy’s JsonObjectBuilderResult and JsonArrayBuilderResult.
package blog.jsonp.moxy;
import java.util.*;
import javax.json.*;
import javax.json.stream.JsonGenerator;
import javax.xml.bind.*;
import org.eclipse.persistence.jaxb.JAXBContextProperties;
import org.eclipse.persistence.oxm.json.*;
public class MarshalDemo {
public static void main(String[] args) throws Exception {
// Create the EclipseLink JAXB (MOXy) Marshaller
Map<String, Object> jaxbProperties = new HashMap<String, Object>(2);
jaxbProperties.put(JAXBContextProperties.MEDIA_TYPE, "application/json");
jaxbProperties.put(JAXBContextProperties.JSON_INCLUDE_ROOT, false);
JAXBContext jc = JAXBContext.newInstance(new Class[] {Customer.class},
jaxbProperties);
Marshaller marshaller = jc.createMarshaller();
// Create the JsonArrayBuilder
JsonArrayBuilder customersArrayBuilder = Json.createArrayBuilder();
// Build the First Customer
Customer customer = new Customer();
customer.setId(1);
customer.setFirstName("Jane");
customer.setLastName(null);
PhoneNumber phoneNumber = new PhoneNumber();
phoneNumber.setType("cell");
phoneNumber.setNumber("555-1111");
customer.getPhoneNumbers().add(phoneNumber);
// Marshal the First Customer Object into the JsonArray
JsonArrayBuilderResult result =
new JsonArrayBuilderResult(customersArrayBuilder);
marshaller.marshal(customer, result);
// Build List of PhoneNumer Objects for Second Customer
List<PhoneNumber> phoneNumbers = new ArrayList<PhoneNumber>(2);
PhoneNumber workPhone = new PhoneNumber();
workPhone.setType("work");
workPhone.setNumber("555-2222");
phoneNumbers.add(workPhone);
PhoneNumber homePhone = new PhoneNumber();
homePhone.setType("home");
homePhone.setNumber("555-3333");
phoneNumbers.add(homePhone);
// Marshal the List of PhoneNumber Objects
JsonArrayBuilderResult arrayBuilderResult = new JsonArrayBuilderResult();
marshaller.marshal(phoneNumbers, arrayBuilderResult);
customersArrayBuilder
// Use JSR-353 APIs for Second Customer's Data
.add(Json.createObjectBuilder()
.add("id", 2)
.add("firstName", "Bob")
.addNull("lastName")
// Included Marshalled PhoneNumber Objects
.add("phoneNumbers", arrayBuilderResult.getJsonArrayBuilder())
)
.build();
// Write JSON to System.out
Map<String, Object> jsonProperties = new HashMap<String, Object>(1);
jsonProperties.put(JsonGenerator.PRETTY_PRINTING, true);
JsonWriterFactory writerFactory = Json.createWriterFactory(jsonProperties);
JsonWriter writer = writerFactory.createWriter(System.out);
writer.writeArray(customersArrayBuilder.build());
writer.close();
}
}Output
Below is the output from running the marshal demo (MarshalDemo). The highlighted portions (lines 2-12 and 18-25) correspond to the portions that were populated from our Java model.
[
{
"id":1,
"firstName":"Jane",
"lastName":null,
"phoneNumbers":[
{
"type":"cell",
"number":"555-1111"
}
]
},
{
"id":2,
"firstName":"Bob",
"lastName":null,
"phoneNumbers":[
{
"type":"work",
"number":"555-2222"
},
{
"type":"home",
"number":"555-3333"
}
]
}
]Unmarshal Demo
MOXy enables you to unmarshal from a JSR-353 JsonStructure (JsonObject or JsonArray). To do this simply wrap the JsonStructure in an instance of MOXy’s JsonStructureSource and use one of the unmarshal operations that takes an instance of Source.
package blog.jsonp.moxy;
import java.io.FileInputStream;
import java.util.*;
import javax.json.*;
import javax.xml.bind.*;
import org.eclipse.persistence.jaxb.JAXBContextProperties;
import org.eclipse.persistence.oxm.json.JsonStructureSource;
public class UnmarshalDemo {
public static void main(String[] args) throws Exception {
try (FileInputStream is = new FileInputStream("src/blog/jsonp/moxy/input.json")) {
// Create the EclipseLink JAXB (MOXy) Unmarshaller
Map<String, Object> jaxbProperties = new HashMap<String, Object>(2);
jaxbProperties.put(JAXBContextProperties.MEDIA_TYPE, "application/json");
jaxbProperties.put(JAXBContextProperties.JSON_INCLUDE_ROOT, false);
JAXBContext jc = JAXBContext.newInstance(new Class[] {Customer.class},
jaxbProperties);
Unmarshaller unmarshaller = jc.createUnmarshaller();
// Parse the JSON
JsonReader jsonReader = Json.createReader(is);
// Unmarshal Root Level JsonArray
JsonArray customersArray = jsonReader.readArray();
JsonStructureSource arraySource = new JsonStructureSource(customersArray);
List<Customer> customers =
(List<Customer>) unmarshaller.unmarshal(arraySource, Customer.class)
.getValue();
for(Customer customer : customers) {
System.out.println(customer.getFirstName());
}
// Unmarshal Nested JsonObject
JsonObject customerObject = customersArray.getJsonObject(1);
JsonStructureSource objectSource = new JsonStructureSource(customerObject);
Customer customer = unmarshaller.unmarshal(objectSource, Customer.class)
.getValue();
for(PhoneNumber phoneNumber : customer.getPhoneNumbers()) {
System.out.println(phoneNumber.getNumber());
}
}
}
}Input (input.json)
The following JSON input will be converted to a JsonArray using a JsonReader.
[
{
"id":1,
"firstName":"Jane",
"lastName":null,
"phoneNumbers":[
{
"type":"cell",
"number":"555-1111"
}
]
},
{
"id":2,
"firstName":"Bob",
"lastName":null,
"phoneNumbers":[
{
"type":"work",
"number":"555-2222"
},
{
"type":"home",
"number":"555-3333"
}
]
}
]Output
Below is the output from running the unmarshal demo (UnmarshalDemo).
Jane Bob 555-2222 555-3333
