Convert Java Object to Json String using Jackson API

Last Updated : 10 May, 2022

JSON stands for JavaScript Object Notation. It's a standard text-based format that shows structured data based on JavaScript object syntax. It is commonly used for transmitting data in web applications. JSON is highly recommended to transmit data between a server and web application. In order to convert a Java object into JSON, the following two methods can be used that are as listed below as follows:

GSON
JACKSON API

Java object is converted into JSON using Jackson API.

Steps to Convert Java Object to JSON String

Step 1: Add jar files of Jackson (in the case of the Maven project add Jackson dependencies in the pom.xml file)

html

<dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>2.5.3</version>
</dependency>

Now pom.xml file is depicted below as follows:

File: Geeks/pom.xml

Step 2: Create a POJO (Plain Old Java Object) to be converted into JSON

Java

// Java Program to Illustrate Organisation Class

package com.Geeks;

// Importing required classes
public class Organisation {

    // Class data members
    private String organisation_name;
    private String description;
    private int Employees;

    // Calling getters and setters

    // Getter
    public String getOrganisation_name()
    {
        return organisation_name;
    }

    // Setter
    public void
    setOrganisation_name(String organisation_name)
    {
        this.organisation_name = organisation_name;
    }

    // Getter
    public String getDescription() { return description; }

    // Setter
    public void setDescription(String description)
    {
        this.description = description;
    }

    // Getter
    public int getEmployees() { return Employees; }

    // Setter
    public void setEmployees(int employees)
    {
        Employees = employees;
    }

    // Method
    // Creating toString
    @Override public String toString()
    {
        // Returning attributes of organisation
        return "Organisation [organisation_name="
            + organisation_name
            + ", description=" + description
            + ", Employees=" + Employees + "]";
    }
}

Step 3: Create a Java class for converting the Organisation object into JSON.

Convert the object into JSON using ObjectMapper class of Jackson API.

Java

// Java Program to Illustrate Object to JSON Conversion

package com.Geeks;

// Importing required classes
import com.Geeks.Organisation;
import java.io.IOException;
import org.codehaus.jackson.map.ObjectMapper;

// Class
public class ObjectToJson {

    // Main driver method
    public static void main(String[] a)
    {
        // Creating object of Organisation
        Organisation org = new Organisation();

        // Insert the data into the object
        org = getObjectData(org);

        // Creating Object of ObjectMapper define in Jackson
        // Api
        ObjectMapper Obj = new ObjectMapper();

        // Try block to check for exceptions
        try {

            // Getting organisation object as a json string
            String jsonStr = Obj.writeValueAsString(org);

            // Displaying JSON String on console
            System.out.println(jsonStr);
        }

        // Catch block to handle exceptions
        catch (IOException e) {

            // Display exception along with line number
            // using printStackTrace() method
            e.printStackTrace();
        }
    }

    // Method
    // Getting the data to be inserted
    // into the object
    public static Organisation
    getObjectData(Organisation org)
    {

        // Insert the custom data
        org.setName("GeeksforGeeks");
        org.setDescription(
            "A computer Science portal for Geeks");
        org.setEmployees(2000);

        // Returning the object
        return org;
    }