What is the role of the Pageable and Page interfaces in pagination?

Table of Contents

• Introduction
• Role of Pageable and Page Interfaces
  • 1. Pageable Interface
    • Example: Creating a Pageable Object
  • 2. Page Interface
    • Example: Handling a Page Object
• Practical Examples
  • Example 1: Paginated Query with Pageable
  • Example 2: Sorting with Pageable
  • Example 3: Using Page Metadata
• Conclusion

Introduction

Pagination is essential for handling large datasets efficiently in web applications. In Spring Data JPA, the Pageable and Page interfaces play a crucial role in simplifying and structuring paginated queries. The Pageable interface defines pagination parameters like page size and sort order, while the Page interface provides the results in a structured manner. This guide explores their roles and how to use them effectively.

Role of Pageable and Page Interfaces

1. Pageable Interface

The Pageable interface defines the pagination parameters sent with a query. It allows you to specify:

• Page Number: The zero-based index of the page to retrieve.
• Page Size: The number of records per page.
• Sort Order: The criteria for sorting the data (e.g., ascending or descending).

Example: Creating a Pageable Object

• PageRequest.of: Creates a pageable instance with page number, size, and sort.
• This example retrieves the first page with 10 records sorted by the name field in ascending order.

2. Page Interface

The Page interface encapsulates the results of a paginated query, including:

• Content: The list of entities on the current page.
• Metadata: Information about the total number of pages, total elements, and whether it's the first or last page.

Example: Handling a Page Object

• This example prints page details and the content of the current page.

Practical Examples

Example 1: Paginated Query with Pageable

Suppose you have an Employee entity and want to fetch employees page by page.

Repository Code:

Service Code:

Example 2: Sorting with Pageable

Retrieve employees with pagination and sort them by their lastName.

Service Code:

Example 3: Using Page Metadata

Display the total number of pages and employees in a controller.

Controller Code:

Conclusion

The Pageable and Page interfaces in Spring Data JPA streamline the process of implementing pagination in web applications. While Pageable defines the pagination and sorting criteria, the Page interface structures the results, providing essential metadata about the dataset. Together, they offer a powerful way to manage large datasets efficiently, ensuring better performance and user experience in your applications.