Package com.fasterxml.jackson.databind

Basic data binding (mapping) functionality that allows for reading JSON content into Java Objects (POJOs) and JSON Trees (JsonNode), as well as writing Java Objects and trees as JSON.

See: Description

Interface Summary

Interface	Description
BeanProperty	Bean properties are logical entities that represent data that Java objects (POJOs (Plain Old Java Objects), sometimes also called "beans") contain; and that are accessed using accessors (methods like getters and setters, fields, constructor parameters).
JsonSerializable	Interface that can be implemented by objects that know how to serialize themselves to JSON, using JsonGenerator (and SerializerProvider if necessary).
Module.SetupContext	Interface Jackson exposes to modules for purpose of registering extended functionality.

Class Summary

Class	Description
AbstractTypeResolver	Defines interface for resolvers that can resolve abstract types into concrete ones; either by using static mappings, or possibly by materializing implementations dynamically.
AnnotationIntrospector	Abstract class that defines API used for introspecting annotation-based configuration for serialization and deserialization.
AnnotationIntrospector.ReferenceProperty	Value type used with managed and back references; contains type and logic name, used to link related references
BeanDescription	Basic container for information gathered by ClassIntrospector to help in constructing serializers and deserializers.
BeanProperty.Bogus	Alternative "Null" implementation that can be used in cases where a non-null BeanProperty is needed
BeanProperty.Std	Simple stand-alone implementation, useful as a placeholder or base class for more complex implementations.
DatabindContext	Shared base class for DeserializationContext and SerializerProvider, context objects passed through data-binding process.
DeserializationConfig	Object that contains baseline configuration for deserialization process.
DeserializationContext	Context for the process of deserialization a single root-level value.
InjectableValues	Abstract class that defines API for objects that provide value to "inject" during deserialization.
InjectableValues.Std	Simple standard implementation which uses a simple Map to store values to inject, identified by simple String keys.
JavaType	Base class for type token classes used both to contain information and as keys for deserializers.
JsonDeserializer<T>	Abstract class that defines API used by ObjectMapper (and other chained JsonDeserializers too) to deserialize Objects of arbitrary types from JSON, using provided JsonParser.
JsonDeserializer.None	This marker class is only to be used with annotations, to indicate that no deserializer is configured.
JsonMappingException.Reference	Simple bean class used to contain references.
JsonNode	Base class for all JSON nodes, which form the basis of JSON Tree Model that Jackson implements.
JsonSerializable.Base	Base class with minimal implementation, as well as couple of extension methods that core Jackson databinding makes use of.
JsonSerializer<T>	Abstract class that defines API used by ObjectMapper (and other chained JsonSerializers too) to serialize Objects of arbitrary types into JSON, using provided JsonGenerator.
JsonSerializer.None	This marker class is only to be used with annotations, to indicate that no serializer is configured.
KeyDeserializer	Abstract class that defines API used for deserializing JSON content field names into Java Map keys.
KeyDeserializer.None	This marker class is only to be used with annotations, to indicate that no deserializer is configured.
MappingIterator<T>	Iterator exposed by ObjectMapper when binding sequence of objects.
MappingJsonFactory	Sub-class of JsonFactory that will create a proper ObjectCodec to allow seam-less conversions between JSON content and Java objects (POJOs).
Module	Simple interface for extensions that can be registered with ObjectMapper to provide a well-defined set of extensions to default functionality; such as support for new data types.
ObjectMapper	ObjectMapper provides functionality for reading and writing JSON, either to and from basic POJOs (Plain Old Java Objects), or to and from a general-purpose JSON Tree Model (JsonNode), as well as related functionality for performing conversions.
ObjectMapper.DefaultTypeResolverBuilder	Customized TypeResolverBuilder that provides type resolver builders used with so-called "default typing" (see ObjectMapper.activateDefaultTyping(PolymorphicTypeValidator) for details).
ObjectReader	Builder object that can be used for per-serialization configuration of deserialization parameters, such as root type to use or object to update (instead of constructing new instance).
ObjectWriter	Builder object that can be used for per-serialization configuration of serialization parameters, such as JSON View and root type to use.
ObjectWriter.GeneratorSettings	Helper class used for containing settings specifically related to (re)configuring JsonGenerator constructed for writing output.
ObjectWriter.Prefetch	As a minor optimization, we will make an effort to pre-fetch a serializer, or at least relevant TypeSerializer, if given enough information.
PropertyMetadata	Simple container class used for storing "additional" metadata about properties.
PropertyMetadata.MergeInfo	Helper class used for containing information about expected merge information for this property, if merging is expected.
PropertyName	Simple value class used for containing names of properties as defined by annotations (and possibly other configuration sources).
PropertyNamingStrategy	Class that defines how names of JSON properties ("external names") are derived from names of POJO methods and fields ("internal names"), in cases where they are not auto-detected and no explicit annotations exist for naming.
PropertyNamingStrategy.KebabCaseStrategy	Naming strategy similar to PropertyNamingStrategy.SnakeCaseStrategy, but instead of underscores as separators, uses hyphens.
PropertyNamingStrategy.LowerCaseStrategy	Simple strategy where external name simply only uses lower-case characters, and no separators.
PropertyNamingStrategy.LowerCaseWithUnderscoresStrategy	Deprecated In 2.7 use PropertyNamingStrategy.SnakeCaseStrategy instead
PropertyNamingStrategy.LowerDotCaseStrategy	Naming strategy similar to PropertyNamingStrategy.KebabCaseStrategy, but instead of hyphens as separators, uses dots.
PropertyNamingStrategy.PascalCaseStrategy	Deprecated In 2.7 use PropertyNamingStrategy.UpperCamelCaseStrategy instead
PropertyNamingStrategy.PropertyNamingStrategyBase
PropertyNamingStrategy.SnakeCaseStrategy	A PropertyNamingStrategy that translates typical camel case Java property names to lower case JSON element names, separated by underscores.
PropertyNamingStrategy.UpperCamelCaseStrategy	A PropertyNamingStrategy that translates typical camelCase Java property names to PascalCase JSON element names (i.e., with a capital first letter).
SequenceWriter	Writer class similar to ObjectWriter, except that it can be used for writing sequences of values, not just a single value.
SerializationConfig	Object that contains baseline configuration for serialization process.
SerializerProvider	Class that defines API used by ObjectMapper and JsonSerializers to obtain serializers capable of serializing instances of specific types; as well as the default implementation of the functionality.

Enum Summary

Enum	Description
AnnotationIntrospector.ReferenceProperty.Type
DeserializationFeature	Enumeration that defines simple on/off features that affect the way Java objects are deserialized from JSON
MapperFeature	Enumeration that defines simple on/off features to set for ObjectMapper, and accessible (but not changeable) via ObjectReader and ObjectWriter (as well as through various convenience methods through context objects).
ObjectMapper.DefaultTyping	Enumeration used with ObjectMapper.activateDefaultTyping(PolymorphicTypeValidator) to specify what kind of types (classes) default typing should be used for.
SerializationFeature	Enumeration that defines simple on/off features that affect the way Java objects are serialized.

Exception Summary

Exception	Description
JsonMappingException	Checked exception used to signal fatal problems with mapping of content, distinct from low-level I/O problems (signaled using simple IOExceptions) or data encoding/decoding problems (signaled with JsonParseException, JsonGenerationException).
RuntimeJsonMappingException	Wrapper used when interface does not allow throwing a checked JsonMappingException

Package com.fasterxml.jackson.databind Description

Basic data binding (mapping) functionality that allows for reading JSON content into Java Objects (POJOs) and JSON Trees (JsonNode), as well as writing Java Objects and trees as JSON. Reading and writing (as well as related additional functionality) is accessed through ObjectMapper, ObjectReader and ObjectWriter classes. In addition to reading and writing JSON content, it is also possible to use the general databinding functionality for many other data formats, using Jackson extension modules that provide such support: if so, you typically simply construct an ObjectMapper with different underlying streaming parser, generator implementation.

The main starting point for operations is ObjectMapper, which can be used either directly (via multiple overloaded readValue, readTree, writeValue and writeTree methods, or it can be used as a configurable factory for constructing fully immutable, thread-safe and reusable ObjectReader and ObjectWriter objects.

In addition to simple reading and writing of JSON as POJOs or JSON trees (represented as JsonNode, and configurability needed to change aspects of reading/writing, mapper contains additional functionality such as:

• Value conversions using ObjectMapper.convertValue(Object, Class), ObjectMapper.valueToTree(Object) and ObjectMapper.treeToValue(com.fasterxml.jackson.core.TreeNode, Class) methods.
• Type introspection needed for things like generation of Schemas (like JSON Schema, Avro Schema, or protoc definitions), using ObjectMapper.acceptJsonFormatVisitor(Class, com.fasterxml.jackson.databind.jsonFormatVisitors.JsonFormatVisitorWrapper) (note: actual handles are usually provided by various Jackson modules: mapper simply initiates calling of callbacks, based on serializers registered)

Simplest usage is of form:

  final ObjectMapper mapper = new ObjectMapper(); // can use static singleton, inject: just make sure to reuse!
  MyValue value = new MyValue();
  // ... and configure
  File newState = new File("my-stuff.json");
  mapper.writeValue(newState, value); // writes JSON serialization of MyValue instance
  // or, read
  MyValue older = mapper.readValue(new File("my-older-stuff.json"), MyValue.class);

  // Or if you prefer JSON Tree representation:
  JsonNode root = mapper.readTree(newState);
  // and find values by, for example, using a JsonPointer expression:
  int age = root.at("/personal/age").getValueAsInt(); 

For more usage, refer to ObjectMapper, ObjectReader and ObjectWriter Javadocs.