How do you create a custom pagination response in Spring Boot?

Table of Contents

Introduction

In Spring Boot applications, pagination is a powerful feature, especially when dealing with large datasets. By default, Spring Data provides a Page object that includes metadata such as the total number of elements, the current page, and the page size. However, there are times when you may want to customize the pagination response to suit the needs of your application or frontend.

In this guide, we’ll show you how to create a custom pagination response in Spring Boot. This will involve modifying the default structure of the pagination response, adding additional metadata, or changing how the pagination information is formatted.

1. Understanding the Default Pagination Response

Spring Boot, when using Spring Data repositories, returns a Page object in response to paginated queries. This object contains the paginated content and several metadata fields like total pages, total elements, page number, and size.

Here’s an example of the default Page object:

The default pagination includes the following:

  • content: List of paginated data (e.g., products).
  • totalElements: Total number of items.
  • totalPages: Total number of pages.
  • size: Number of items per page.
  • number: Current page number (0-based).

However, you may want to format this response differently or include additional metadata. Let’s see how to customize the pagination response.

2. Creating a Custom Pagination Response Class

To customize the pagination response, we can create a custom class that will structure the pagination response the way we want. For example, we can add extra fields like nextPage, previousPage, or even links to provide URLs for navigating through pages.

Example: Custom Pagination Response Class

Explanation:

  • Generic Class: CustomPageResponse<T> is a generic class, meaning you can reuse it for any type of data (e.g., Product, User, etc.).
  • Additional Fields: The class includes custom fields such as hasNext and hasPrevious to indicate whether there are more pages of data available.
  • Constructor: The constructor allows us to set all the pagination data at once.

3. Mapping Page to CustomPageResponse

Next, you need to convert the default Page object to your custom pagination response. This can be done in the service layer where you fetch the paginated data.

Example: Mapping Page to Custom Response in Service Layer

Explanation:

  • **PageRequest.of(page, size)**: Creates a Pageable object based on the requested page and size.
  • **productRepository.findAll(pageable)**: Fetches the paginated data from the repository.
  • The Page object is then mapped to the CustomPageResponse object.

4. Returning Custom Pagination Response in Controller

Finally, in the controller layer, you can return the custom pagination response.

Example: Controller Layer

Explanation:

  • The getPaginatedProducts method in the controller accepts the page and size parameters from the request and calls the service layer to get the paginated results.

5. Custom Pagination Response Example

Here’s an example of what the custom pagination response might look like when returned by the controller:

Explanation:

  • The response now includes hasNext and hasPrevious, which provide more context about the pagination state.
  • You can further customize this response format by adding more fields like first, last, or even links to the next and previous pages.

Conclusion

Creating a custom pagination response in Spring Boot allows you to provide more flexible and detailed metadata to the client, improving the overall API experience. By extending the default Page object and mapping it to a custom response class, you can add any additional fields needed for your application. This customization can be tailored to include information such as nextPage, previousPage, and more, making it easier for your frontend to handle pagination effectively.

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