Jackson

External

• Jackson Documentation Hub: https://github.com/FasterXML/jackson-docs
• Jackson JSON Processor Wiki http://wiki.fasterxml.com/JacksonHome
• Jackson in Five Minutes http://wiki.fasterxml.com/JacksonInFiveMinutes
• Jackson JSON Tutorial http://www.baeldung.com/jackson
• javadocs:
  • Jackson Core https://github.com/FasterXML/jackson-core/wiki
  • Jackson Core Annotations https://github.com/FasterXML/jackson-annotations/wiki
  • Jackson Databind https://github.com/FasterXML/jackson-databind/wiki

Internal

• JSON

Overview

Jackson is a Java library for processing JSON data format. It has support for marshaling and unmarshalling Java to and from JSON. It has a JAX-RS content handler that can automatically convert between Java objects and JSON, and vice-versa. It can generate JSON schemas from a Java object model.

JSON Processing Methods

Jackson offers three alternative methods for processing JSON:

Streaming API

The Streaming API reads and writes JSON as a series of discrete events, in a mode called "incremental parsing/generation". The concepts behind the Streaming API are similar to those of StAX. The Streaming API has the lowest overhead and its the fastest of all methods. The other two methods (Tree Model and Data Binding) are built in top of it. However, this is not the most convenient method, because is relatively low level. All content to read or write has to be processed in the order the input comes or the output has to go out. Random access is not possible. Also, no Java objects are created, unless specifically requested, and even then only very basic types are supported: String and byte[].

The central elements of the Streaming API are the parsers (org.codehaus.jackson.JsonParser) that are used for reading JSON content, and the generators (org.codehaus.jackson.JsonGenerator) that are used for writing Java state out as JSON.

This is an example of how to create a parser that reads JSON from a file and parses it:

This is an example of how to create a generator that writes JSON from Java state:

Tree Model

Tree model is arguably the most flexible of all three methods.

Data Binding

Data Binding is arguably the most convenient of all three methods.

JSON to Java

JSON to Java

Java to JSON

Java to JSON

TODO and delete: https://home.feodorov.com:9443/wiki/Wiki.jsp?page=Jackson

Maven Support

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-core</artifactId>
    <version>2.8.7</version>
</dependency>