Conversion of JSON Object Array to Java POJO

In this article, we will learn how to use the widely used Jackson JSON library to map an array of JSON items to a Java POJO class instance.

Prerequisites

• A basic understanding of Java programming.
• A JSON library for Java, such as Jackson, Gson, or org.json, depending on your preference.

Implementation to Convert an Array of JSON Object to Java POJO

Below are the steps and their implementations to convert an array of JSON items to a Java POJO class instance.

Step 1: Create a Maven Project

Open any preferred IDE and create a new Maven project. Here we will be using IntelliJ IDEA, we can do this by selecting File -> New -> Project.. -> Maven and following the wizard.

Step 2: Add Jackson Dependency to POM.xml

Now, we will add Jackson dependencies to the XML file.

<dependencies>
 <!-- Other dependencies -->
 <dependency>
 <groupId>com.fasterxml.jackson.core</groupId>
 <artifactId>jackson-databind</artifactId>
 <version>2.12.5</version> <!-- Use the latest version available -->
 </dependency>
</dependencies>

Step 3: Create the Java POJO Class

After adding dependency to the pom.xml file, we will now create a POJO class named User.

User.java

The User class defines a POJO to map JSON data with name and age properties. Getters and setters are provided for Jackson to populate objects.

Step 4: In the Main class add logic of Conversion JSON to POJO

Output:

Name: Ram, Age: 30
Name: Sita, Age: 25

Explanation of the Code:

• The above main class converts the JSON data into the POJO class, so initially it defines the JSON string representing an array of objects with name and age properties.
• Then it initializes the ObjectMapper to parse JSON. Then the mapper reads the JSON string and also maps it to the array. Finally, the user catches the JSON structure.
• A loop is used to print the values, allowing the JSON data to be easily converted to Java objects.