Simplify JSON Serialization in SpringBoot with Jackson

Table of Contents

1. Introduction
2. Using Jackson in Spring Boot
3. Enabling Data Wrapping
4. Creating a Simple Spring Boot Application
5. Testing the Application
6. Creating a Controller
7. Using Lombok for Code Generation
8. Returning JSON Data
9. Enabling Wrapping in Jackson
10. Formatting JSON Output

Introduction

In this article, we will discuss how to enable data wrapping in a Spring Boot application using the Jackson library. We will begin by setting up a simple Spring Boot application and testing its functionality. Then, we will Create a controller and use Lombok for code generation. Next, we will examine the process of returning JSON data and explore the concept of data wrapping. Finally, we will enable data wrapping in Jackson and format the JSON output for better readability.

1. Using Jackson in Spring Boot

Before diving into data wrapping, let's understand the basics of using Jackson in a Spring Boot application. Jackson is a popular library that provides functionality for serializing and deserializing JSON data. It allows us to convert Java objects to JSON and vice versa. By default, Spring Boot includes the Jackson library, so we can use it out of the box.

2. Enabling Data Wrapping

Data wrapping refers to the process of encapsulating an object inside a key when serializing it to JSON. By default, Jackson does not enable data wrapping. However, we can enable it by using a specific annotation or configuring an application property. In this article, we will focus on enabling data wrapping using an application property.

3. Creating a Simple Spring Boot Application

To demonstrate how to enable data wrapping in Jackson, let's start by creating a simple Spring Boot application. We will use the Spring Initializr to generate the project structure.

1. Open your preferred IDE and navigate to the Spring Initializr Website (link: https://start.spring.io/).
2. Select the desired project settings, such as project Type, language, and dependencies.
3. Click on the "Generate" button to download the project.
4. Extract the downloaded project and import it into your IDE.

4. Testing the Application

Before enabling data wrapping, let's ensure that our application is working correctly. To do this, we will create a controller and test if we can access the JSON data it returns.

1. Create a new Package named "controller" in the source folder.
2. Inside the "controller" package, create a new class named "UserController".
3. Add the necessary annotations to mark the class as a controller.
4. Create a simple method that returns a STRING response.
5. Add a @RequestMapping annotation to specify the endpoint URL.
6. Run the application and test if the controller is up and running by accessing the endpoint in a browser.

5. Creating a Controller

Now that we have confirmed our application is working, let's create a controller to handle our data manipulation requests. In this example, we will use the UserController class to demonstrate the process.

1. Open the UserController class.
2. Remove any unnecessary code.
3. Add the necessary annotations to mark the class as a controller.
4. Create a method that returns a User object.
5. Use the Lombok library's annotations to reduce boilerplate code.
6. Build the User object using the User.builder().build() method.
7. Customize the User object's properties (name, age) as desired.
8. Return the User object from the method.

6. Using Lombok for Code Generation

To simplify the process of creating and managing our User object, we will utilize the Lombok library. Lombok provides annotations that automatically generate getters, setters, and other boilerplate code during compilation. This saves us time and effort in writing repetitive code.

1. Add the Lombok dependency to the project.
2. Enable annotation processing in your IDE.
3. Add the @NoArgsConstructor, @AllArgsConstructor, and @Builder annotations to the User class.
4. Remove any existing constructors and getters/setters.

7. Returning JSON Data

At this point, we have a controller that returns a User object when accessed. However, the response is currently being returned as plain text. To return the data as JSON, we need to add the necessary annotations and dependencies.

1. Add the @RestController annotation to the UserController class.
2. Add the @ResponseBody annotation to the method that returns the User object.
3. Make sure the necessary dependencies for JSON serialization are present in your project.

8. Enabling Wrapping in Jackson

Now that our application is returning JSON data, let's move on to enabling data wrapping in Jackson. By default, Jackson does not wrap the serialized object with a key. However, we can enable this feature by configuring an application property.

1. Open the application.properties file.
2. Add the following property: spring.jackson.serialization.WRAP_ROOT_VALUE=true.
3. Save the changes and restart the application.

9. Formatting JSON Output

After enabling data wrapping, we may Notice that the JSON output is not very readable. To improve the readability, we can enable indentation and pretty-printing of the JSON data.

1. Open the application.properties file.
2. Add the following property: spring.jackson.serialization.INDENT_OUTPUT=true.
3. Save the changes and restart the application.

Conclusion

In this article, we have explored how to enable data wrapping in a Spring Boot application using the Jackson library. We started by setting up a simple Spring Boot application and testing its functionality. Then, we created a controller and used Lombok for code generation. Next, we examined the process of returning JSON data and explored the concept of data wrapping. Finally, we enabled data wrapping in Jackson and formatted the JSON output for better readability. By following these steps, You can enhance your Spring Boot application and gain more control over the serialization and deserialization process.

Highlights

• Jackson is a popular library for serializing and deserializing JSON data in Spring Boot applications.
• Enabling data wrapping in Jackson involves configuring a Spring Boot application property.
• Lombok is a useful library for reducing boilerplate code in Java applications.
• By using Lombok annotations, we can easily generate getters, setters, and other commonly used methods.
• Returning JSON data in a Spring Boot application requires the proper configuration and dependencies.
• Enabling data wrapping allows us to encapsulate objects inside a key when serializing them to JSON.
• By formatting the JSON output with indentation, we can improve its readability and understandability.

FAQ

Q: Can I enable data wrapping in Jackson without using an application property? A: Yes, data wrapping can also be enabled by creating a Jackson configuration file. However, this method requires additional setup and is outside the scope of this article.

Q: How can I configure the wrapping key name in Jackson? A: You can specify the wrapping key name by using the @JsonRootName annotation on the class you want to serialize. This annotation allows you to provide a custom name for the wrapping key.

Q: Does enabling data wrapping affect deserialization as well? A: Yes, enabling data wrapping in Jackson affects both serialization and deserialization. When deserializing JSON data, Jackson expects the wrapped object to include the specified wrapping key.