Jackson Tutorial

Jackson is a high-performance JSON processor used for Java. It is the most popular library used for serializing Java objects or Map to JSON and vice-versa. It is completely based on Java. Jackson tutorial provides all the basic and advanced concepts of the Jackson library.

JSON is one of the most important data interchange formats that is mainly used in the world of Web applications. JSON requests can be easily parsed by the browser can be easily converted into JavaScript objects but cannot be easily converted into Java objects.

Serialization and deserialization are two important concepts when working with JSON. Serialization is a process of converting Java objects into JSON whereas deserialization is a process of converting JSON into Java objects.

• We need a parser for parsing Json or converting them into Java Objects. We parse JSON into Object because it is not that easy to work with JSON strings.
• Jackson is a Java Json library that has a built-in ObjectMapper class. The ObjectMapper class is responsible for parsing the JSON files and deserializing them into Java objects.
• It provides JSON Parser and JSON Generator that helps us in parsing and generating json one token at a time.

Features of Jackson library

Jackson library has the following features:

1. Easy to use

In order to simplify the common use cases, Jackson provides a high-level façade.

2. Performance

Jackson library is quite fast and has a low memory footprint. It is suitable for large systems.

3. No Dependency

In order to use Jackson, there is no need to use any other library except JDK. JDK is required because Jackson is based on Java.

4. Mapping free

There is no need to create mapping because it is by default provided for most of the objects to be serialized.

5. Open Source

It is freely available in the market. There is no need to purchase anything to use Jackson library. Just download it and use it in the code.

6. Clean JSON

It converts an object or a Map into a clean and compact JSON that is very easy to read.

Processing JSON

In order to process JSON, Jackson provides three ways which are as follows:

1. Streaming API

By using streaming API, JSON data read and write as discrete events. Streaming API provides JsonParser and JsonGenerator for reading and writing data, respectively. Streaming API is one of the fastest and lowest overheads in read/write operations. It is the most powerful approach among others.

2. Tree Model

For reading and writing JSON data, it creates a tree representation of JSON documents. The ObjectMapper class is used to create a tree of nodes (JsonNode). However, it is not as faster as streaming API, but it is the most flexible approach for reading and writing JSON data.

3. Data Binding

It is a way to convert POJO to JSON and JSON to POJO. It is done by using annotations or a property accessor. Data binding is of two types, i.e., Simple Data Binding and Full Data Binding.

Simple Data Binding is used to convert JSON to and from null Object, Map, List, String, Number, and Boolean.

Full Data Binding is used to convert JSON to and from any of the Java types.

Prerequisite

Jackson is completely based on Java, so before proceeding with this tutorial, it is required that you should have knowledge of Java.

Audience

This tutorial is helpful for the fresher and more experienced Java developers. This tutorial covers all the basics of the Jackson library.

Problem

We assure you that will not find any problem with this Jackson Tutorial. But if there is any mistake, please post the problem in the contact form.