Jackson Simple Data Binding: Difference between revisions

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=Overview=
=Overview=


Simple data binding extracts data from JSON and initializes an in-memory Java object hierarchy. Unlike the [[Jackson#Tree_Model|tree model]], which uses <tt>JsonNode</tt>s, simple data binding assembles the hierarchy out of Maps, Lists, Strings, Numbers, Booleans and nulls to represent the JSON structure. A Map/List/String/Number/Boolean hierarchy can be written out as JSON content.
Simple data binding extracts data from JSON and initializes an in-memory Java object hierarchy. Unlike the [[Jackson#Tree_Model|tree model]], which uses <tt>JsonNode</tt>s, simple data binding assembles the hierarchy representing the JSON data out of Maps, Lists, Strings, Numbers, Booleans and nulls. A Map/List/String/Number/Boolean hierarchy can be written out as JSON content.


=JSON to Java=
=JSON to Java=

Revision as of 20:19, 26 February 2017

Internal

Overview

Simple data binding extracts data from JSON and initializes an in-memory Java object hierarchy. Unlike the tree model, which uses JsonNodes, simple data binding assembles the hierarchy representing the JSON data out of Maps, Lists, Strings, Numbers, Booleans and nulls. A Map/List/String/Number/Boolean hierarchy can be written out as JSON content.

JSON to Java

JSON to Java parsing is done by ObjectMapper.readValue(), which must be called with a type corresponding to the top-level JSON data type, usually a Map.


type and it will build a Map/List/String/Number/Boolean hierarchy:
import com.fasterxml.jackson.databind.ObjectMapper;

ObjectMapper om = new ObjectMapper();

Map root = on.readValue(inputStream, Map.class);

Most generically:

Object root = mapper.readValue(src, Object.class);

It is possible to enable generic type information (like Map<String, Object>). For details, see Full Data Binding.

JSON to Java Code Example

https://github.com/NovaOrdis/playground/blob/master/json/jackson/simple-data-binding-json-to-java/src/main/java/io/novaordis/playground/json/jackson/simpledatabinding/json2java/Main.java

Java to JSON

ObjectMapper om = new ObjectMapper();

Map root = ...

om.writeValue(baos, root);

Java to JSON Code Example