• JacksonDocumentation

Jackson Documentation

General

• Jackson Tutorial: the best place to start; covers basic processing approaches and covers common usage patterns.

• Jackson FAQ covers many common questions regarding typical usage.

• Jackson JavaDocs has extensive and detailed coverage of all the features: what is available, where, how. But you do need to know where to look.

• Jackson User Group is a site/group/social network dedicated to all things Jackson, for sharing knowledge about how to use Jackson efficiently.

• Using Jackson with Smile (binary JSON) format: JacksonForSmile

Features, general

To learn more about how to configure Jackson, check out:

• Jackson annotation guide (related: support for JAXB annotations)

• Simple on/off Features

• Configuration settings for handling "non-standard JSON"

• Adding custom handlers:

  • Adding custom serializers

  • Adding custom deserializers

Usage Patterns

This mini-series from Cowtalk is useful for seeing bigger picture.

How to work with:

• Immutable Objects

• Open Content (extensible, loose or partial content definitions)

• Filtering properties

• Polymorphic Types (by Programmer Bruce)

By functionality:

• Polymorphic type handling: http://programmerbruce.blogspot.com/2011/05/deserialize-json-with-jackson-into.html

• Abstract type materialization: Mr Bean, aka "abstract type materialization" (also, see "Materialized Beans" page)

By (alternate) data format:

• XML: http://www.cowtowncoder.com/blog/archives/2012/03/entry_467.html } Jackson 2.0: also works with XML!

• CSV: (to be added)

Features by Release

New functionality is being introduced with new releases, and sometimes it is useful to know what is the minimum version that has specific set of functionality you need; or to evaluate whether upgrade to a new version would make sense. To help with this, there are separate release pages for recent (and sometimes upcoming) Jackson releases:

• 2.1 Features (Oct 2012)

• 2.0 Features (Feb 2012).

  • Upgrading from 1.9 to 2.0

• 1.9 Features (Oct 2011).

• 1.8 Features (Apr 2011).

• 1.7 Features (Jan 2011). Highlights:

  • Module interface (and multiple module projects!), Dynamic filters, Contextual (de)serializers

• 1.6 Features (Sep 2010). Highlights:

  • mr. Bean, Smile ("binary JSON") format, Bi-directional references (parent/child), updateValue (not just create)

• 1.5 Features (Mar 2010). Highlights:

  • Polymorphic type handling

• 1.4 Features (Dec 2009). Highlights:

  • JSON Views

• 1.3 Features (Oct 2009)

• 1.2 Features (Aug 2009). Highlights:

  • Mix-in Annotations, Use any constructor (not just default)

• 1.1 Features (Jun 2009). Highlights:

  • Support for JAXB annotations, JSON Schema generation, Support fields too (not just methods)

• 1.0 Features (May 2009). Hightlights:

  • 3 fundamental operating models: Full data binding, JSON Tree model, Streaming API

HOW-TOs, samples

Here is some sample code, contributed by Jackson users on mailing lists. It is not intended to define official or canonical way of doing things, but showing possible alternatives -- and if you do end up finding better ways, or have incremental improvement suggestions, please let us know so we can update samples!

• How-to Ignore Unknown properties in JSON content?

• Basic:

  • Servlet/javascript sample code

  • Simple POJO mappper

  • Dyna-beans? (extensible beans)

• Intermediate:

  • Custom date handling

  • "Jackson serialization narrowed" -- how to exclude informations when serializing objects using JSON views, @JsonIgnore, mix-in annotations

• Advanced:

  • Jackson Type Proxy for extremely dynamic generation of types

  • Quoting JSON String characters -- in case your clients can not handle all legal Unicode characters.

  • Custom JSON View implementation (contributed by Andrei V)

  • Jackson to rescue: how to handle one-to-many fields from ORM (parent / child)

  • Prevent cross-site scripting when using JSON objects...: How to add custom String serializer to add escaping, quoting, using latest (1.7) features.

Term Glossary

Term Glossary contains list of commonly referred internal terms, such as names of often-used core classes.

Best Practices

• Thread-safety

• Performance

Related extension projects

Beyond core Jackson project and its deliverables, there are related external projects that can solve problems with third party libaries and data types, and even non-Java JVM languages or non-JSON data formats:

• Jackson Modules offer pluggable extensions for third-party datatypes or non-Java JVM languages.

• Jackson outside of JSON page lists projects that aim to support data formats other than JSON, but using Jackson data binding functionality.

Forward-looking

• TODO list

• Known Issues (higher level ones: for bugs and feature requests, check out Jackson Jira at Codehaus)

External docs

General:

• "Easy JSON with Jackson"

• "JSON Strings and Java Objects"

• "Parsing a large JSON file efficiently and easily"

• Batchfb User Guide + Basic Jackson Tutorial (nice tutorial right after explaining basics of the Lib itself)

Jackson with frameworks:

• iBeans (Mule):

  • "Using JSON bindings with iBeans"

• Play framework:

  • Jackson, Jerkson with Play

• Restlet:

  • Jackson extension for Restlet

• Spring:

  • "Create JSON response for AJAX request in spring 3.0"

• Ext-JS (plus others, Spring MVC, Hibernate, ...)

  • Multiple useful articles at In the Folds, including:

    • Ext JS – Serialize Date using Jackson and Spring 3

    • The Journey for Handling Hibernate Lazy Loading using Spring 3 MVC Annotations and Jackson for JSON

Jackson with non-Java JVM languages:

• Groovy:

  • Groovy++ in action: statically typed dynamic dispatch

• Scala: see JacksonModuleScala

Performance:

• Performance comparison of Protocol Buffers, JSON et al formats, libs.

• Basic JSON parsing performance in Java (Cowtowncoder.com)

• JSON data binding performance with 3 JSON data binding libs: Jackson, Google-gson, Json-lib (Cowtowncoder.com)

• Json Java parsers / generators microbenchmark

• On Android:

  • relative to Protocol Buffers

  • compared to other Java JSON libs

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