Jackson Simple Data Binding

Internal

• Jackson

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 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.

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);