JSON Support in Java EE 8

Copyright © 2017, Oracle and/or its affiliates. All rights reserved.
JSON Support in Java EE 8
JSON-P, JSON-B, Yasson
Dmitry Kornilov
JSONB/P Specifications Lead
@m0mus
28 Aug 2017

Safe Harbor Statement
The following is intended to outline our general product direction. It is intended for
information purposes only, and may not be incorporated into any contract. It is not a
commitment to deliver any material, code, or functionality, and should not be relied upon
in making purchasing decisions. The development, release, and timing of any features or
functionality described for Oracle’s products remains at the sole discretion of Oracle.
2

Copyright © 2017, Oracle and/or its affiliates. All rights reserved. 3
Dmitry Kornilov
• Senior Manager @ Oracle
• JSON-B (JSR-367) spec lead
• JSON-P (JSR-374) spec lead
• Outstanding Spec Lead 2016
• EclipseLink project committer

Program Agenda
Introduction
JSON Processing
JSON Binding / Yasson
Q & A
1
2
3
5
4

Introduction
5

What is JSON???

This is Jason
7

This is also Jason
8

This is JSON-B
9

What is JSON?
• JavaScript Object Notation
• Subset of JavaScript
• Lightweight data-interchange format
• Object, Array, Value
10
{
"name": "Jason Bourne",
"age": 35,
"phoneNumbers": [
{
"type": "home",
"number": "123-456-789"
}
]
}

JSON Support in Java EE 8
• JSON Processing API
– Standard API to parse, generate, transform, query JSON
– Object Model and Streaming API
• similar to DOM and StAX
• JSON Binding API
– Binding JSON documents to Java objects
• similar to JAXB
11

JSON Processing
12

JSON-P Links
• JSON-P Public Web Site
– https://javaee.github.io/jsonp/
• GitHub
– https://github.com/javaee/jsonp
• JCP
– https://jcp.org/en/jsr/detail?id=374
• Discussion Groups
– https://javaee.groups.io/g/jsonp-spec
13

Maven Dependencies
14

<dependency>
<groupId>org.glassfish</groupId>
<artifactId>javax.json</artifactId>
<version>1.1</version>
</dependency>

<dependency>
<groupId>javax.json</groupId>
<artifactId>javax.json-api</artifactId>
</dependency>

JSON-P
• Streaming API
– JsonParser
– JsonGenerator
• Object model API
– JsonReader
– JsonWriter
– JsonPointer
– JsonPatch
– JsonMergePatch
15

JsonParser
• JsonParser
– Parses JSON in a streaming way from input sources
– Similar to StAX’s XMLStreamReader, a pull parser
• Created using:
• Json.createParser(…), Json.createParserFactory().createParser(…)
• Optionally, configured with features
• Parser state events:
– START_ARRAY, START_OBJECT, KEY_NAME, VALUE_STRING, VALUE_NUMBER,
VALUE_TRUE, VALUE_FALSE, VALUE_NULL, END_OBJECT, END_ARRAY
16

JsonParser
{
"name":
"Jason Bourne",
"age":
35,
"phoneNumbers":
[
{
"type": "home",
"number": "123-456-789"
}
]
}

JsonParser
START_OBJECT{
"name":
"Jason Bourne",
"age":
35,
"phoneNumbers":
[
{
"type": "home",
"number": "123-456-789"
}
]
}

JsonParser
START_OBJECT
KEY_NAME
{
"name":
"Jason Bourne",
"age":
35,
"phoneNumbers":
[
{
"type": "home",
"number": "123-456-789"
}
]
}

JsonParser
START_OBJECT
KEY_NAME
VALUE_STRING
{
"name":
"Jason Bourne",
"age":
35,
"phoneNumbers":
[
{
"type": "home",
"number": "123-456-789"
}
]
}

JsonParser
START_OBJECT
KEY_NAME
VALUE_STRING
KEY_NAME
{
"name":
"Jason Bourne",
"age":
35,
"phoneNumbers":
[
{
"type": "home",
"number": "123-456-789"
}
]
}

JsonParser
START_OBJECT
KEY_NAME
VALUE_STRING
KEY_NAME
VALUE_NUMBER
{
"name":
"Jason Bourne",
"age":
35,
"phoneNumbers":
[
{
"type": "home",
"number": "123-456-789"
}
]
}

JsonParser
START_OBJECT
KEY_NAME
VALUE_STRING
KEY_NAME
VALUE_NUMBER
KEY_NAME
{
"name":
"Jason Bourne",
"age":
35,
"phoneNumbers":
[
{
"type": "home",
"number": "123-456-789"
}
]
}

JsonParser
START_OBJECT
KEY_NAME
VALUE_STRING
KEY_NAME
VALUE_NUMBER
KEY_NAME
START_ARRAY
{
"name":
"Jason Bourne",
"age":
35,
"phoneNumbers":
[
{
"type": "home",
"number": "123-456-789"
}
]
}

JsonParser
START_OBJECT
KEY_NAME
VALUE_STRING
KEY_NAME
VALUE_NUMBER
KEY_NAME
START_ARRAY
START_OBJECT
{
"name":
"Jason Bourne",
"age":
35,
"phoneNumbers":
[
{
"type": "home",
"number": "123-456-789"
}
]
}

JsonParser
START_OBJECT
KEY_NAME
VALUE_STRING
KEY_NAME
VALUE_NUMBER
KEY_NAME
START_ARRAY
START_OBJECT
KEY_NAME, VALUE_STRING
{
"name":
"Jason Bourne",
"age":
35,
"phoneNumbers":
[
{
"type": "home",
"number": "123-456-789"
}
]
}

JsonParser
START_OBJECT
KEY_NAME
VALUE_STRING
KEY_NAME
VALUE_NUMBER
KEY_NAME
START_ARRAY
START_OBJECT
{
"name":
"Jason Bourne",
"age":
35,
"phoneNumbers":
[
{
"type": "home",
"number": "123-456-789"
}
]
}

JsonParser
START_OBJECT
KEY_NAME
VALUE_STRING
KEY_NAME
VALUE_NUMBER
KEY_NAME
START_ARRAY
START_OBJECT
END_OBJECT
{
"name":
"Jason Bourne",
"age":
35,
"phoneNumbers":
[
{
"type": "home",
"number": "123-456-789"
}
]
}

JsonParser
START_OBJECT
KEY_NAME
VALUE_STRING
KEY_NAME
VALUE_NUMBER
KEY_NAME
START_ARRAY
START_OBJECT
END_OBJECT
END_ARRAY
{
"name":
"Jason Bourne",
"age":
35,
"phoneNumbers":
[
{
"type": "home",
"number": "123-456-789"
}
]
}

JsonParser
START_OBJECT
KEY_NAME
VALUE_STRING
KEY_NAME
VALUE_NUMBER
KEY_NAME
START_ARRAY
START_OBJECT
END_OBJECT
END_ARRAY
END_OBJECT
{
"name":
"Jason Bourne",
"age":
35,
"phoneNumbers":
[
{
"type": "home",
"number": "123-456-789"
}
]
}

JsonParser
{
"name":
"Jason Bourne",
"age":
35,
"phoneNumbers":
[
{
"type": "home",
"number": "123-456-789"
}
]
}
JsonParser parser = Json.createParser(...);

JsonParser
{
"name":
"Jason Bourne",
"age":
35,
"phoneNumbers":
[
{
"type": "home",
"number": "123-456-789"
}
]
}
Event e = parser.next(); // START_OBJECT

JsonParser
{
"name":
"Jason Bourne",
"age":
35,
"phoneNumbers":
[
{
"type": "home",
"number": "123-456-789"
}
]
}
parser.next(); // KEY_NAME

JsonParser
{
"name":
"Jason Bourne",
"age":
35,
"phoneNumbers":
[
{
"type": "home",
"number": "123-456-789"
}
]
}
parser.getString(); // name

JsonParser
{
"name":
"Jason Bourne",
"age":
35,
"phoneNumbers":
[
{
"type": "home",
"number": "123-456-789"
}
]
}
parser.next(); // VALUE_STRING

JsonParser
{
"name":
"Jason Bourne",
"age":
35,
"phoneNumbers":
[
{
"type": "home",
"number": "123-456-789"
}
]
}
parser.getString(); // Jason Bourne

JsonParser
{
"name":
"Jason Bourne",
"age":
35,
"phoneNumbers":
[
{
"type": "home",
"number": "123-456-789"
}
]
}

JsonParser
{
"name":
"Jason Bourne",
"age":
35,
"phoneNumbers":
[
{
"type": "home",
"number": "123-456-789"
}
]
}
parser.getString(); // age

JsonParser
{
"name":
"Jason Bourne",
"age":
35,
"phoneNumbers":
[
{
"type": "home",
"number": "123-456-789"
}
]
}
parser.next(); // VALUE_NUMBER

JsonParser
{
"name":
"Jason Bourne",
"age":
35,
"phoneNumbers":
[
{
"type": "home",
"number": "123-456-789"
}
]
}
parser.next(); // VALUE_NUMBER
parser.getInt(); // 35

JsonGenerator
• Generates JSON in a streaming way to output sources
– Similar to StAX’s XMLStreamWriter
• Created using:
– Json.createGenerator(…)
– Json.createGeneratorFactory().createGenerator(…)
• Optionally, configured with features
– e.g. pretty printing
• Allows method chaining
41

JsonGenerator
JsonGenerator ge=Json.createGenerator(…);
ge.writeStartArray()
.writeStartObject()
.write("type", "home”)
.write("number", "123-456-789")
.writeEnd()
.writeStartObject()
.write("type", "fax”)
.write("number", "123-456-790")
.writeEnd()
.writeEnd()
.close();
[
{
"type": "home”,
"number": "123-456-789"
},
{
"type": "fax”,
"number": "123-456-790"
}
]

Object Model API
• Builder to build JsonObject and JsonArray from scratch
• Allows method chaining
• Type-safe (cannot mix array and object building methods)
• Can also use existing JsonObject and JsonArray in a builder
43

Object Model API
JsonArray value = Json.createArrayBuilder()
.add(Json.createObjectBuilder()
.add("type", "home")
.add("number", "123-456-789")
.build();
)
.add(Json.createObjectBuilder()
.add("type", "fax")
.add("number", "123-456-790")
.build()
)
.build();
[
{
"type": "home”,
"number": "123-456-789"
},
{
"type": "fax”,
"number": "123-456-790"
}
]

JSON-P 1.1
• Update JSON-P spec to stay current with emerging standards (RFC 7159)
• Support for IETF standards on
– JSON Pointer (RFC 6901)
– JSON Patch (RFC 6902)
– JSON Merge Patch (RFC 7396)
• Add editing/transformation operations to JSON objects and arrays
• Support for a streaming API, together with Collectors
• Support for processing big JSON, e.g. add filters to JSON parsing.
45

JsonPointer
• IETF RFC 6901
• String syntax for identifying a specific value
– /phone/mobile
– /parents/0
• Special characters
– "/" —> "~1"
– "~" —> "~0"
46

JSON Pointer Sample
JsonArray jasons = . . .;
JsonPointer pointer =
Json.createPointer("/1/profession");
JsonValue profession =
pointer.getValue(jasons);
pointer.replace(jasons,
Json.createValue("Super agent"));
47
[
{
"name": "Jason Voorhees",
"profession": "Maniac killer",
"age": 45
},
{
"age": 35
}
]

JsonPatch
• IETF RFC 6902
• Modify Parts of JSON document
• Patch is a JSON document itself
• Operations:
– Add, replace, remove, move, copy, test
• HTTP PATCH method (application/json-patch+json)
48

JSON Patch Sample
[
{ "op": "replace",
"path": "/1/profession",
"value": "Super agent" },
{ "op": "remove",
"path": "/2" }
]
[
{
"age": 45
},
{
"age": 35
},
{
"name": "James Bond",
"profession": "Agent 007",
"age": 40
}
]

JSON Patch Sample
[
{ "op": "replace",
{ "op": "remove",
"path": "/2" }
]
[
{
"age": 45
},
{
"profession": "Super agent",
"age": 35
},
{
"name": "James Bond",
"profession": "Agent 007",
"age": 40
}
]

JSON Patch Sample
[
{ "op": "replace",
{ "op": "remove",
"path": "/2" }
]
[
{
"age": 45
},
{
"age": 35
}
]

JSON Binding / Yasson
52

• JSON-B (JSON Binding)
– API and Specification
– JSR-367
– Part of Java EE 8
53
JSON-B and Yasson
• Yasson
– Reference Implementation
– Eclipse Foundation Project
– Part of GlassFish 5
– Used by WAS Liberty

Links
• JSON-B web site
– Official web: http://json-b.net
– GitHub repo: https://github.com/javaee/jsonb-spec
– JCP page: https://www.jcp.org/en/jsr/detail?id=367
– Groups: https://javaee.groups.io/g/jsonb-spec
• Yasson
– Web site: https://projects.eclipse.org/projects/rt.yasson
– GitHub repo: https://github.com/eclipse/yasson
54

Maven Dependencies
55

<dependency>
<groupId>javax.json.bind</groupId>
<artifactId>javax.json.bind-api</artifactId>
</dependency>

<dependency>
<groupId>org.eclipse</groupId>
<artifactId>yasson</artifactId>
</dependency>
<repositories>
<repository>
<id>Yasson Snapshots</id>
<url>https://repo.eclipse.org/content/repositories/
yasson-snapshots/</url>
</repository>
</repositories>

JSON Binding
• API to serialize/deserialize Java objects to/from JSON documents
– Similar to JAX-B
– Standardizes the current technologies (Jackson, Genson, Gson)
• Default mapping between classes and JSON
• Customization APIs
– Annotations (@JsonbProperty, @JsonbNillable)
– Runtime configuration builder
• Natural follow on to JSON-P
– Closes the JSON support gap
– Allows to change providers
56

• No configuration, no annotations
• The scope:
– Basic Types
– Specific JDK Types
– Dates
– Classes
– Collections/Arrays
– Enumerations
– JSON-P
57
Default Mapping
import javax.json.bind.Jsonb;
import javax.json.bind.JsonbBuilder;
// Create with default config
Jsonb jsonb = JsonbBuilder.create();

JSON-B Engine
public interface Jsonb extends AutoCloseable {
<T> T fromJson(String str, Class<T> type);
<T> T fromJson(String str, Type runtimeType);
<T> T fromJson(Reader reader, Class<T> type);
<T> T fromJson(Reader reader, Type runtimeType);
<T> T fromJson(InputStream stream, Class<T> type);
<T> T fromJson(InputStream stream, Type runtimeType);
String toJson(Object object);
String toJson(Object object, Type runtimeType);
void toJson(Object object, Writer writer);
void toJson(Object object, Type runtimeType, Writer writer);
void toJson(Object object, OutputStream stream);
void toJson(Object object, Type runtimeType, OutputStream stream);
}

JSON-B Sample
59
Person person1 = new Person();
person1.setName("Jason Voorhees");
person1.setProfession("Maniac killer");
person1.setAge(45);
Person person2 = new Person();
person2.setName("Jason Bourne");
person2.setProfession("Super agent");
person2.setAge(35);
List<Person> persons = new ArrayList<>();
persons.add(person1);
persons.add(person2);
Jsonb jsonb = JsonbBuilder.create();
jsonb.toJson(persons);
[
{
"age": 45
},
{
"age": 35
}
]

Basic Types
– java.lang.String
– java.lang.Character
– java.lang.Byte (byte)
– java.lang.Short (short)
– java.lang.Integer (int)
– java.lang.Long (long)
– java.lang.Float (float)
– java.lang.Double (double)
– java.lang.Boolean (boolean)
Specific Types
– java.math.BigInteger
– java.math.BigDecimal
– java.net.URL
– java.net.URI
– java.util.Optional
– java.util.OptionalInt
– java.util.OptionalLong
– java.util.OptionalDouble
60
Basic and Specific Types

Date/Time
61
java.util.Date ISO_DATE_TIME
java.util.Calendar, java.util.GregorianCalendar ISO_DATE if to time information present, otherwise ISO_DATE_TIME
Java.util.TimeZone, java.util.SimpleTimeZone NormalizedCustomId (see TimeZone javadoc)
java.time.Instant ISO_INSTANT
java.time.LocalDate ISO_LOCAL_DATE
java.time.LocalTime ISO_LOCAL_TIME
java.time.LocalDateTime ISO_LOCAL_DATE_TIME
java.time.ZonedDateTime ISO_ZONED_DATE_TIME
java.time.OffsetDateTime ISO_OFFSET_DATE_TIME
java.time.OffsetTime ISO_OFFSET_TIME
java.time.ZoneId NormalizedZoneId as specified in ZoneId javadoc
java.time.ZoneOffset NormalizedZoneId as specified in ZoneOffset javadoc
java.time.Duration ISO 8601 seconds based representation
java.time.Period ISO 8601 period representation

Date/Time Samples
62
// java.util.Date
SimpleDateFormat sdf = new SimpleDateFormat("dd.MM.yyyy");
Date parsedDate = sdf.parse("15.11.2016");
jsonb.toJson(parsedDate)); // ”2016-11-15T00:00:00"
// java.util.Calendar
Calendar dateCalendar = Calendar.getInstance();
dateCalendar.clear();
dateCalendar.set(2016, 11, 15);
jsonb.toJson(dateCalendar); // ”2016-11-15”
// java.time.Instant
jsonb.toJson(Instant.parse("2016-11-15T23:00:00Z")); // ”2016-11-15T23:00:00Z”
// java.time.Duration
jsonb.toJson(Duration.ofHours(5).plusMinutes(4)); // “PT5H4M"
// java.time.Period
jsonb.toJson(Period.between(
LocalDate.of(1960, Month.JANUARY, 1),
LocalDate.of(1970, Month.JANUARY, 1))); // "P10Y"

Arrays/Collections
• Collection
• Map
• Set
• HashSet
• NavigableSet
• SortedSet
• TreeSet
• LinkedHashSet
• HashMap
• NavigableMap
• SortedMap
• TreeMap
• LinkedHashMap
• List
• ArrayList
• LinkedList
• Deque
• ArrayDeque
• Queue
• PriorityQueue
63

• javax.json.JsonArray
• javax.json.JsonStructure
• javax.json.JsonValue
• javax.json.JsonPointer
• javax.json.JsonString
• javax.json.JsonNumber
• javax.json.JsonObject
64
JSON-P Types
// JsonObject
JsonBuilderFactory f =
Json.createBuilderFactory(null);
JsonObject jsonObject =
f.createObjectBuilder()
.add(“name", "Jason Bourne")
.add(“city", "Prague")
.build();
jsonb.toJson(jsonObject);

Classes
• Public and protected nested and static nested classes
• Anonymous classes (serialization only)
• Inheritance is supported
• Default no-argument constructor is required for deserialization
65

Fields
• Final fields are serialized
• Static fields are skipped
• Transient fields are skipped
• Null fields are skipped
• Fields order
– Lexicographical order
– Parent class fields are serialized before child class fields
66

public class Parent {
public int parentB;
public int parentA;
}
{
"parentA": 1,
"parentB": 2
}
67
Fields Order Sample

public class Parent {
public int parentB;
public int parentA;
}
public class Child extends Parent {
public int childB;
public int childA;
}
{
"parentA": 1,
"parentB": 2
}
{
"parentA": 1,
"parentB": 2,
"childA": 3,
"childB": 4
}
68
Fields Order Sample

Serialization
• Existing fields with public getters
• Public fields with no getters
• Public getter/setter pair without a
corresponding field
Deserialization
• Existing fields with public setters
• Public fields with no setters
• Public getter/setter pair without a
corresponding field
69
Scope and Field Access Strategy

public class Foo {
public final int publicFinalField;
private final int privateFinalField;
public static int publicStaticField;
public int publicWithNoGetter;
public int publicWithPrivateGetter;
public Integer publicNullField = null;
private int privateWithNoGetter;
private int privateWithPublicGetter;
public int getNoField() {};
public void setNoField(int value) {};
}
{
"publicFinalField": 1,
"publicWithNoGetter": 1,
"privateWithPublicGetter": 1,
"noField": 1
}
70
Scope and Field Access Strategy

• Annotations
• Runtime configuration
– JsonbConfig
– JsonbBuilder
71
JSON-B Engine Configuration
JsonbConfig config = new JsonbConfig()
.withFormatting(…)
.withNullValues(…)
.withEncoding(…)
.withStrictIJSON(…)
.withPropertyNamingStrategy(…)
.withPropertyOrderStrategy(…)
.withPropertyVisibilityStrategy(…)
.withAdapters(…)
.withBinaryDataStrategy(…);
Jsonb jsonb = JsonbBuilder.newBuilder()
.withConfig(…)
.withProvider(…)
.build();

Customizations
• Property names
• Property order
• Ignoring properties
• Null handling
• Custom instantiation
• Fields visibility
• Date/Number Formats
• Binary Encoding
• Adapters
• Serializers/Deserializers

• Annotation
– @JsonbProperty
• Scope:
– Field
– Getter/Setter
– Parameter
73
Property Names
public class Customer {
private int id;
@JsonbProperty("name")
public String firstName;
}
public int id;
public String firstName;
@JsonbProperty("name")
public String getFirstName() {
return firstName;
}
}

Property Naming Strategy
• Supported naming strategies
– IDENTITY (myMixedCaseProperty)
– LOWER_CASE_WITH_DASHES (my-mixed-case-property)
– LOWER_CASE_WITH_UNDERSCORES (my_mixed_case_property)
– UPPER_CAMEL_CASE (MyMixedCaseProperty)
– UPPER_CAMEL_CASE_WITH_SPACES (My Mixed Case Property)
– CASE_INSENSITIVE (mYmIxEdCaSePrOpErTy)
– Or a custom implementation
• JsonbConfig
– withPropertyNamingStrategy(…):
74

• Strategies:
– LEXICOGRAPHICAL (A-Z)
– ANY
– REVERSE (Z-A)
• Annotation
– @JsonbPropertyOrder on class
• JsonbConfig
– withPropertyOrderStrategy(…)
75
Property Order Strategy
@JsonbPropertyOrder(ANY)
public class Foo {
public int bar2;
public int bar1;
}

• Annotation
– @JsonbTransient
76
Ignoring Properties
public int id;
public String name;
@JsonbTransient
public BigDecimal salary;
}

• PropertyVisibilityStrategy
interface
• Annotation
– @JsonbVisibility
• JsonbConfig
– withPropertyVisibilityStrategy(…)
77
Property Visibility
public interface PropertyVisibilityStrategy {
boolean isVisible(Field field);
boolean isVisible(Method method);
}
public class MyStrategy implements
PropertyVisibilityStrategy {
/* ... */
}
@JsonbVisibility(MyStrategy.class)
public class Bar {
private int field1;
private int field2;
}

• Null fields are skipped by default
• Annotation
– @JsonbNillable
• JsonbConfig
– withNullValues(true)
78
Null Handling
public int id = 1;
@JsonbProperty("name", true)
public String name = null;
}
@JsonbNillable
public int id = 1;
public String name = null;
}

Custom Instantiation
79
public int id;
public String name;
@JsonbCreator
public static Customer create(
@JsonbProperty("id") int id) {
return CustomerDao.getByPrimaryKey(id);
}
}
public class Order {
public int id;
public Customer customer;
}
{
"id": 123,
"customer": {
"id": 562,
}
}

• Annotations
– @JsonbDateFormat
– @JsonbNumberFormat
• JsonbConfig
– withDateFormat(…)
– withLocale(…)
80
Date/Number Format
public class FormatSample {
public Date defaultDate;
@JsonbDateFormat("dd.MM.yyyy")
public Date formattedDate;
public BigDecimal defaultNumber;
@JsonbNumberFormat(“#0.00")
public BigDecimal formattedNumber;
}

• Supported encodings
– BYTE (default)
– BASE_64
– BASE_64_URL
• JsonbConfig
– withBinaryDataStrategy(…)
81
Binary Data Encoding
.withBinaryDataStrategy(
BinaryDataStrategy.BASE_64);
Jsonb jsonb = JsonbBuilder.create(config);
String json = jsonb.toJson(obj);

I-JSON
• I-JSON (”Internet JSON”) is a restricted profile of JSON
– https://tools.ietf.org/html/draft-ietf-json-i-json-06
• JSON-B fully supports I-JSON by default with three exceptions:
– JSON Binding does not restrict the serialization of top-level JSON texts that are
neither objects nor arrays. The restriction should happen at application level.
– JSON Binding does not serialize binary data with base64url encoding.
– JSON Binding does not enforce additional restrictions on dates/times/duration.
• JsonbConfig
– withStrictIJSON(true)
82

• Inspired by JAXB
• Annotations
– @JsonbTypeAdapter annotation
• JsonbConfig
– withAdapters(…)
83
Adapters
public interface JsonbAdapter<Original, Adapted> {
Adapted adaptToJson(Original obj);
Original adaptFromJson(Adapted obj);
}
@JsonbTypeAdapter(AnimalAdapter.class)
public Animal animal;
.withAdapters(new AnimalAdapter());

• Low level control on
serialization/deserialization
• Annotations
– @JsonbTypeSerializer
– @JsonbTypeDeserializer
• JsonbConfig
– withSerializers(…)
– withDeserializers(…)
84
Serializers/Deserializers
public interface JsonbSerializer<T> {
void serialize(T obj, JsonGenerator generator,
SerializationContext ctx);
public interface JsonbDeserializer<T> {
T deserialize(JsonParser parser,
DeserializationContext ctx, Type rtType);
}
@JsonbTypeSerializer(AnimalSerializer.class)
@JsonbTypeDeserializer(AnimalDeserializer.class)
public Animal animal;
.withSerializers(new AnimalSerializer())
.withDeserializers(new AnimalDeserializer());

JSON-B Demo
• GitHub
– https://github.com/m0mus/json_demo
• Demonstrates
– JSON-P
• JsonParser
• JsonGenerator
• Working with large files
• JsonPointer
• JsonPatch
• Using Java8 streams
85
– JSON-B
• Default mapping
• Adapters
• Serializers/Deserializers
• Mapping of generic class
• Using together with JSON-P

Q & A
86

JSON Support in Java EE 8

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