🎓 Top 15 Udemy Courses (80-90% Discount): My Udemy Courses - Ramesh Fadatare — All my Udemy courses are real-time and project oriented courses.

▶️ Subscribe to My YouTube Channel (178K+ subscribers): Java Guides on YouTube

▶️ For AI, ChatGPT, Web, Tech, and Generative AI, subscribe to another channel: Ramesh Fadatare on YouTube

1. Overview

The Jackson library in Java provides a myriad of annotations to control the serialization and deserialization of Java objects to and from JSON format. One such annotation, which comes in handy when handling multiple possible names for a property during deserialization, is @JsonAlias. In this post, we will explore its use within the context of an Employee Management System.

@JsonAlias Annotation Overview

Introduced in Jackson 2.9, the @JsonAlias annotation provides an alternative means to define one or more alternative names for a property during the deserialization process. This is especially useful when the incoming JSON might have different field names for the same property.

2. Development Steps

1. Set up a new Maven project.

2. Incorporate the essential Jackson dependencies.

3. Craft an Employee class utilizing the @JsonAlias annotation.

4. Develop a main class for demonstration and testing purposes.

5. Deserialize sample JSON data into the Employee object.

3. Create a Maven Project

There are different ways to create a simple Maven project:
Create a Simple Maven Project using the Command Line Interface
Create a Simple Maven Project using Eclipse IDE
Create a Simple Maven Project using IntelliJ IDEA

4. Maven Dependencies

Open the pom.xml file, and add the following Jackson data binding dependency:

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.13.0</version>
</dependency>

5. Code Program

Below are the classes for our Employee Management System:
// Employee.java
public class Employee {
    private int id;
    @JsonAlias({ "fullName", "full_name" })
    private String name;
    // Standard getters and setters...
}

// MainDemo.java
import com.fasterxml.jackson.databind.ObjectMapper;
public class MainDemo {
    public static void main(String[] args) {
        // JSON with 'fullName'
        String json1 = "{\"id\": 1, \"fullName\": \"John Doe\"}";
        // JSON with 'full_name'
        String json2 = "{\"id\": 2, \"full_name\": \"Jane Smith\"}";
        ObjectMapper mapper = new ObjectMapper();
        try {
            Employee employee1 = mapper.readValue(json1, Employee.class);
            System.out.println("Employee ID: " + employee1.getId() + ", Name: " + employee1.getName());
            Employee employee2 = mapper.readValue(json2, Employee.class);
            System.out.println("Employee ID: " + employee2.getId() + ", Name: " + employee2.getName());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Output:

Employee ID: 1, Name: John Doe
Employee ID: 2, Name: Jane Smith

Code Explanation:

In the Employee class, the name field is annotated with @JsonAlias, accepting both "fullName" and "full_name" as valid JSON field names. This means that while deserializing if either of these names is encountered, they will map to the name field in the Employee class.

The MainDemo class further exemplifies this by successfully deserializing two different JSON strings with different name attributes.

6. Conclusion

The @JsonAlias annotation in Jackson offers an elegant solution for scenarios where incoming JSON might have varying field names for the same Java property. It ensures flexibility and robustness in deserialization processes, making the handling of diverse data sources more straightforward and efficient.

My Top and Bestseller Udemy Courses. The sale is going on with a 70 - 80% discount. The discount coupon has been added to each course below:

Spring Boot + RabbitMQ Course - The Practical Guide

Java Guides

Search This Blog

Java Jackson @JsonAlias

1. Overview

@JsonAlias Annotation Overview

2. Development Steps

3. Create a Maven Project

There are different ways to create a simple Maven project:
Create a Simple Maven Project using the Command Line Interface
Create a Simple Maven Project using Eclipse IDE
Create a Simple Maven Project using IntelliJ IDEA

4. Maven Dependencies

Open the pom.xml file, and add the following Jackson data binding dependency:

5. Code Program

Output:

Code Explanation:

6. Conclusion

My Top and Bestseller Udemy Courses. The sale is going on with a 70 - 80% discount. The discount coupon has been added to each course below:

Build REST APIs with Spring Boot 4, Spring Security 7, and JWT

[NEW] Learn Apache Maven with IntelliJ IDEA and Java 25

ChatGPT + Generative AI + Prompt Engineering for Beginners

Spring 7 and Spring Boot 4 for Beginners (Includes 8 Projects)

Building Real-Time REST APIs with Spring Boot - Blog App

Building Microservices with Spring Boot and Spring Cloud

Java Full-Stack Developer Course with Spring Boot and React JS

Build 5 Spring Boot Projects with Java: Line-by-Line Coding

Testing Spring Boot Application with JUnit and Mockito

Spring Boot Thymeleaf Real-Time Web Application - Blog App

Master Spring Data JPA with Hibernate

Spring Boot + Apache Kafka Course - The Practical Guide

Java Testing: Mastering JUnit 5 Framework

Reactive Programming in Java: Spring WebFlux and Testing

Spring Boot + RabbitMQ Course - The Practical Guide

Functional Programming in Java (Includes Java Collections)

ChatGPT for Java Developers: Boost Your Productivity with AI

Comments