🎓 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

Jackson is a Java library commonly employed for converting Java objects to their JSON representation and back. At times, there's a need to serialize a Java object in a custom manner. The @JsonValue annotation in Jackson facilitates this by allowing a single method's return value to be considered as the object's representation during serialization.

@JsonValue Annotation Overview

The @JsonValue annotation can be applied to a method in a Java class, indicating that the method's return value should be used as the serialized representation of the object. This is particularly useful when wanting to serialize an object to a more simplified form, like a single String or number.

2. Development Steps

1. Start by setting up a new Maven project.

2. Insert the required Jackson dependencies.

3. Construct the Student class using the @JsonValue annotation.

4. Create a separate class to handle serialization.

5. Implement a main class to display serialization in action.

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

Delving into the Student Management System example:
// Student.java
public class Student {
    private final String firstName;
    private final String lastName;
    public Student(String firstName, String lastName) {
        this.firstName = firstName;
        this.lastName = lastName;
    }
    @JsonValue
    public String toFullName() {
        return firstName + " " + lastName;
    }
    // Other getters, setters, and methods...
}

// StudentSerializer.java
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
public class StudentSerializer {
    public static String serialize(Student student) throws JsonProcessingException {
        ObjectMapper mapper = new ObjectMapper();
        return mapper.writeValueAsString(student);
    }
}

// MainClass.java
public class MainClass {
    public static void main(String[] args) {
        Student student = new Student("John", "Doe");
        try {
            String json = StudentSerializer.serialize(student);
            System.out.println("Serialized JSON: " + json);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }
    }
}

Output:

Serialized JSON: "John Doe"

Code Explanation:

The Student class has a method toFullName() that returns the full name of the student. By annotating this method with @JsonValue, we instruct Jackson to use the return value of this method as the serialized output for the object.

Consequently, instead of the typical JSON object structure, the serialized form is a simple JSON string representing the student's full name.

The StudentSerializer class contains a static method to handle this serialization using Jackson's ObjectMapper.

Finally, the MainClass shows this serialization in action.

6. Conclusion

Jackson's @JsonValue annotation offers developers a powerful tool for customizing the serialized representation of an object. By choosing a specific method's return value as the serialization output, developers can achieve cleaner and more succinct JSON structures, tailored to specific needs.

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 @JsonValue

1. Overview

@JsonValue 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