Mastering JSON Binding API for JEE 8

Mastering JSON Binding API for JEE 8

Table of Contents:

1. Introduction
2. Safe Harbor Statement
3. About the Speaker
4. Project Template Initialization
   • Maven Project Setup
   • Dependencies
5. JSON Parsing with JSON Processing API
   • Introduction to JSON Processing
   • Parsing JSON Document
   • Listing Parts and Values
   • Skipping Parts of Document
6. JSON Generation with JSON Processing API
   • Creating JSON Generator
   • Generating JSON Document
7. Streaming JSON Processing with JSON Processing API
   • Introduction to Streaming API
   • Reading JSON Document with Streaming API
   • Calculating Total in a Shopping Cart
8. JSON Pointer with JSON-P 1.1 API
   • Introduction to JSON Pointer
   • Creating JSON Pointer
   • Applying JSON Pointer to Document
9. JSON Patch with JSON-P 1.1 API
   • Introduction to JSON Patch
   • Creating JSON Patch
   • Applying JSON Patch to Document
10. JSON Binding with JSON Binding API
    • Introduction to JSON Binding
    • Serializing Java Object to JSON
    • Customizing JSON Output
    • Deserializing JSON to Java Object
    • Customizing JSON Input
11. Advanced JSON Binding with Generics
    • Deserializing JSON to Generic List
    • Handling Generic Types

Article: JSON Processing and JSON Binding with Java

JSON (JavaScript Object Notation) has become a popular data interchange format due to its simplicity and readability. In Java, there are libraries and APIs available to process and manipulate JSON data. In this article, we will explore JSON processing and JSON binding using Java.

Introduction

JSON processing and JSON binding are two approaches to work with JSON data in Java. JSON processing involves parsing and generating JSON data, while JSON binding allows for the serialization and deserialization of Java objects to and from JSON.

Safe Harbor Statement

Before diving into the technical details, it's important to note the disclaimer. The information presented here is for demonstration purposes and may not represent the final product. Please exercise caution when making critical decisions Based on this information.

About the Speaker

The speaker, Mitra Cornello, is a JSON processing specialist from Oracle. Being awarded as an outstanding Spec Lead, she is highly experienced in open-source projects, including the Eclipse Link Project.

Project Template Initialization

To get started with JSON processing and JSON binding, we will first initialize a project template that utilizes these technologies. We'll set up a Maven project and add the necessary dependencies.

Maven Project Setup

The project template is a Maven project with a simple structure. It consists of three classes that we'll touch upon while discussing JSON binding.

Dependencies

To use JSON processing and JSON binding in our project, we need to add the required dependencies. These include:

• JSON Processing API (Milestone 1 version)
• JSON Processing Reference Implementation (RI)
• JSON Binding API (Milestone 1 version)
• JSON Binding RI (Yasson)

The project also includes essential plugins for compilation, packaging, and execution.

JSON Parsing with JSON Processing API

JSON Processing API provides functionality to parse and process JSON documents in Java. Let's explore how to parse a JSON document and retrieve parts and values from it.

Introduction to JSON Processing

JSON Processing API offers a set of utility classes and interfaces for parsing, generating, manipulating, and querying JSON data. It includes factories, builders, and event-based APIs to handle JSON documents of varying sizes.

Parsing JSON Document

To parse a JSON document, we Create a JSONParser instance using the JSON class's createParser factory method. We pass an input stream with our JSON document to the parser.

Listing Parts and Values

JSON Processing API allows us to traverse the JSON document and access its parts and values. We can use the parser's hasNext and next methods to iterate over the document's elements and retrieve their names and values.

Skipping Parts of Document

In some cases, we might want to skip certain parts of our JSON document without processing them. JSON Processing API provides methods to skip arrays and objects efficiently. By utilizing these methods, we can improve performance when dealing with large JSON data.

JSON Generation with JSON Processing API

JSON Processing API also supports JSON generation, allowing us to create JSON documents from Java objects. Let's explore how we can Generate JSON using this API.

Creating JSON Generator

To generate JSON, we create a JSONGenerator instance using the JSON class's createGenerator factory method. We pass an output stream to the generator to write our JSON document.

Generating JSON Document

The JSONGenerator provides a builder-like interface to construct the JSON document. We can use methods like writeStartArray, writeStartObject, writeKey, and writeValue to create arrays, objects, and key-value pairs.

Streaming JSON Processing with JSON Processing API

JSON Processing API offers a streaming API that allows us to Read and process large JSON documents efficiently. Let's explore how we can use the streaming API to accomplish specific tasks.

Introduction to Streaming API

The streaming API provides a lightweight and event-based approach to JSON processing. It is suitable for handling large JSON documents where memory efficiency is crucial.

Reading JSON Document with Streaming API

By using the JSONReader class, we can read and process JSON documents using the streaming API. The reader provides methods to retrieve elements, objects, and values from the JSON document in a sequential manner.

Calculating Total in a Shopping Cart

As an example task, let's calculate the total price in a shopping cart JSON document using the streaming API. We'll traverse the document, extract the prices, and sum them up.

JSON Pointer with JSON-P 1.1 API

JSON-P 1.1 introduces JSON Pointer, a feature that allows us to navigate and manipulate JSON documents easily. Let's explore how to create and Apply JSON Pointers in Java.

Introduction to JSON Pointer

JSON Pointer is a STRING representation of a JSON document path. It provides a simple and standardized way to reference specific parts of a JSON document.

Creating JSON Pointer

To create a JSON Pointer, we use the JSON class's createPointer factory method and pass the desired path as a string. The path follows a specific syntax defined by JSON Pointer.

Applying JSON Pointer to Document

Once we have a JSON Pointer, we can use it to extract values or manipulate a JSON document. By applying the JSON Pointer to our document, we can access specific parts and retrieve or modify their values.

JSON Patch with JSON-P 1.1 API

JSON-P 1.1 also introduces JSON Patch, a mechanism to describe changes to a JSON document. Let's explore how to create and apply JSON Patch operations using Java.

Introduction to JSON Patch

JSON Patch is a format for expressing modifications to a JSON document. It provides a structured way to add, remove, or replace JSON document elements.

Creating JSON Patch

To create a JSON Patch, we use the JSON builder pattern with the JSONPatchBuilder class. We can chain multiple patch operations together, specifying the target object and the desired modification.

Applying JSON Patch to Document

Once we have a JSON Patch, we can apply it to a JSON document using the JSONPatch class's apply method. The apply method takes the document and the patch as parameters, returning the modified document.

JSON Binding with JSON Binding API

JSON Binding API provides a way to serialize and deserialize Java objects to and from JSON. Let's explore how to use JSON Binding to map Java objects to JSON representations and vice versa.

Introduction to JSON Binding

JSON Binding allows for the serialization and deserialization of Java objects to JSON. It provides a convenient way to work with JSON data using Java classes and annotations.

Serializing Java Object to JSON

To serialize a Java object to JSON, we create a JSONB instance using the JSONBBuilder class. We can then use the JSONB instance's toJson method to convert the object to its JSON representation.

Customizing JSON Output

JSON Binding API provides various annotations to customize the JSON output. We can change property names, ignore certain properties, and specify order or formatting options using these annotations.

Deserializing JSON to Java Object

To deserialize JSON to a Java object, we again create a JSONB instance. Using the instance's fromJson method, we can convert the JSON representation back into a Java object.

Customizing JSON Input

Just like customizing JSON output, we can also customize the JSON input during deserialization. JSON Binding API offers annotations to handle different JSON formats, such as snake case or kebab case.

Advanced JSON Binding with Generics

JSON Binding API supports generics, allowing us to serialize and deserialize generic Java types. Let's explore how to work with generic types using JSON Binding.

Deserializing JSON to Generic List

Deserializing JSON to a generic List can be accomplished by specifying the generic Type during deserialization. We create a JSONB instance and use the fromJson method with the desired generic type.

Handling Generic Types

When working with generic types, JSON Binding API requires some additional steps to handle the type information properly. We need to extract the generic type information and construct the target type accordingly.

In conclusion, JSON processing and JSON binding are powerful tools for working with JSON data in Java. The APIs offer various functionalities for parsing, generating, manipulating, and binding JSON documents. By utilizing these APIs, developers can seamlessly integrate JSON data into their Java applications.

Note: Remember to exercise caution while making critical business decisions based on JSON data. The information provided here is for demonstration purposes and may not represent the final product.

Highlights:

• JSON Processing API allows for parsing and generating JSON documents.
• JSON Binding API provides serialization and deserialization of Java objects to and from JSON.
• Streaming API is useful for handling large JSON documents efficiently.
• JSON Pointer allows for easy navigation and manipulation of JSON documents.
• JSON Patch provides a standard way to describe modifications to JSON documents.
• JSON Binding supports customization and handling of generic types.

FAQ:

Q: What is the difference between JSON processing and JSON binding? A: JSON processing focuses on parsing and generating JSON data, while JSON binding is used for serialization and deserialization of Java objects to and from JSON.

Q: Can JSON binding customize the JSON output? A: Yes, JSON binding provides various annotations to customize the JSON output, such as changing property names or ordering.

Q: How can JSON binding handle generic types? A: When working with generic types, JSON binding requires extracting the generic type information and constructing the target type accordingly.

Q: Is JSON processing suitable for large JSON documents? A: Yes, JSON processing offers a streaming API that is memory-efficient and suitable for handling large JSON documents.

Q: What is the purpose of JSON Pointer? A: JSON Pointer provides a standardized way to reference specific parts of a JSON document, allowing for easy navigation and manipulation.

Q: Can JSON Patch be used to modify JSON documents? A: Yes, JSON Patch allows for describing modifications to a JSON document, including adding, removing, and replacing elements.