Pagination and sorting with Pageable in Spring Boot - Mini Project: Build & Apply

Pagination and sorting with Pageable in Spring Boot

📖 Scenario: You are building a simple Spring Boot application to manage a list of books in a library. The library has many books, so you want to show the books page by page and allow sorting by title or author.

🎯 Goal: Build a Spring Boot REST controller that returns a paginated and sorted list of books using Spring Data's Pageable interface.

📋 What You'll Learn

Create a list of books as initial data

Add a Pageable parameter to the controller method

Use the Pageable to return a paginated and sorted page of books

Complete the REST controller to handle requests with pagination and sorting

💡 Why This Matters

🌍 Real World

Pagination and sorting are common in web applications to improve user experience by loading data in small chunks and allowing users to order data by different fields.

💼 Career

Understanding how to use Spring Data's Pageable interface is essential for backend developers working with Spring Boot to build scalable and user-friendly APIs.

1

Create initial book data

Create a List<Book> called books with these exact entries: new Book(1L, "Spring Boot Basics", "John Doe"), new Book(2L, "Java Fundamentals", "Jane Smith"), new Book(3L, "REST APIs", "Alice Johnson"), new Book(4L, "Microservices", "Bob Brown").

Spring Boot

import java.util.List;

public class BookController {
    // Create the books list here
    // Your code here
}

Hint

Use List.of() to create an immutable list of Book objects with the exact data.

2

Add Pageable parameter to controller method

Add a public method called getBooks that takes a Pageable pageable parameter and returns a Page<Book>. Do not implement the method body yet.

Spring Boot

import java.util.List;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;

public class BookController {
    List books = List.of(
        new Book(1L, "Spring Boot Basics", "John Doe"),
        new Book(2L, "Java Fundamentals", "Jane Smith"),
        new Book(3L, "REST APIs", "Alice Johnson"),
        new Book(4L, "Microservices", "Bob Brown")
    );

    // Add the getBooks method signature here
    // Your code here
}

Hint

Define the method with the exact name getBooks, return type Page<Book>, and a single parameter Pageable pageable.

3

Implement pagination and sorting logic

Inside the getBooks method, create a PageImpl<Book> object that returns a sublist of books based on pageable.getPageNumber() and pageable.getPageSize(). Use pageable.getSort() to sort the list by title or author before paging.

Spring Boot

import java.util.List;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.PageImpl;
import org.springframework.data.domain.Sort;
import java.util.stream.Collectors;

public class BookController {
    List books = List.of(
        new Book(1L, "Spring Boot Basics", "John Doe"),
        new Book(2L, "Java Fundamentals", "Jane Smith"),
        new Book(3L, "REST APIs", "Alice Johnson"),
        new Book(4L, "Microservices", "Bob Brown")
    );

    public Page getBooks(Pageable pageable) {
        // Sort and paginate the books list here
        // Your code here
    }
}

Hint

Use a stream to sort the books by the properties in pageable.getSort(). Then calculate the start and end indexes for the page and create a PageImpl with the sublist.

4

Complete the REST controller with annotations

Add the @RestController annotation to the class and @GetMapping("/books") to the getBooks method. Add @RequestParam to accept page, size, and sort parameters automatically via Pageable.

Spring Boot

import java.util.List;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.PageImpl;
import org.springframework.data.domain.Sort;
import java.util.stream.Collectors;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;

@RestController
public class BookController {
    List books = List.of(
        new Book(1L, "Spring Boot Basics", "John Doe"),
        new Book(2L, "Java Fundamentals", "Jane Smith"),
        new Book(3L, "REST APIs", "Alice Johnson"),
        new Book(4L, "Microservices", "Bob Brown")
    );

    // Add @GetMapping and @RequestParam annotations here
    // Your code here
}

Hint

Add @RestController above the class and @GetMapping("/books") above the getBooks method to make it a REST endpoint that accepts pagination and sorting parameters.

Practice

1. What is the main purpose of using Pageable in Spring Boot?

easy

A. To fetch data in small chunks with optional sorting

B. To connect to the database directly

C. To write SQL queries manually

D. To handle user authentication

Solution

1. Step 1: Understand Pageable's role

   Pageable is used to request data in pages, not all at once.

2. Step 2: Recognize sorting feature

   It also supports sorting data by fields while fetching pages.

3. Final Answer:

   To fetch data in small chunks with optional sorting -> Option A

4. Quick Check:

   Pageable = Pagination + Sorting [OK]

Hint: Pageable means small pages + sorting [OK]

Common Mistakes:

• Thinking Pageable connects to database
• Confusing Pageable with authentication
• Assuming Pageable writes SQL queries

2. Which of the following is the correct way to create a Pageable object for page 2, size 5, sorted by "name" ascending?

easy

A. PageRequest.of(1, 5, Sort.by("name"))

B. PageRequest.of(2, 5, Sort.asc("name"))

C. PageRequest.of(2, 5, Sort.by("name"))

D. PageRequest.create(2, 5, Sort.by("name"))

Solution

1. Step 1: Understand zero-based page index

   Page numbers start at 0, so page 2 means index 1.

2. Step 2: Check method and sorting syntax

   Use PageRequest.of(page, size, Sort.by("field")) for ascending sort.

3. Final Answer:

   PageRequest.of(1, 5, Sort.by("name")) -> Option A

4. Quick Check:

   Page index zero-based + Sort.by correct [OK]

Hint: Page index starts at 0, so page 2 is index 1 [OK]

Common Mistakes:

• Using page number directly instead of zero-based index
• Using non-existent methods like Sort.asc
• Using PageRequest.create instead of PageRequest.of

3. Given this repository method call:
repository.findAll(PageRequest.of(0, 3, Sort.by("age")))
What will be the result?

medium

A. Error because Sort direction is missing

B. First 3 records sorted by age descending

C. All records without sorting

D. First 3 records sorted by age ascending

Solution

1. Step 1: Analyze PageRequest parameters

   Page 0 means first page, size 3 means 3 records, Sort.by("age") defaults to ascending.

2. Step 2: Understand repository behavior

   findAll with Pageable returns that page of sorted data.

3. Final Answer:

   First 3 records sorted by age ascending -> Option D

4. Quick Check:

   Page 0 + size 3 + ascending sort = first 3 sorted [OK]

Hint: Sort.by defaults to ascending if direction not set [OK]

Common Mistakes:

• Assuming descending sort without direction
• Thinking all records are returned
• Expecting error due to missing direction

4. What is wrong with this code snippet?

Pageable pageable = PageRequest.of(1, 10, Sort.asc("date"));

medium

A. Page index should start at 0, not 1

B. Sort.asc() method does not exist

C. Page size cannot be 10

D. PageRequest.of requires 4 parameters

Solution

1. Step 1: Check Sort method usage

   Spring Data uses Sort.by(), not Sort.asc().

2. Step 2: Verify other parameters

   Page index 1 and size 10 are valid; PageRequest.of takes 3 parameters here.

3. Final Answer:

   Sort.asc() method does not exist -> Option B

4. Quick Check:

   Use Sort.by() for sorting [OK]

Hint: Use Sort.by(), not Sort.asc() [OK]

Common Mistakes:

• Using Sort.asc() or Sort.desc() which don't exist
• Thinking page index must be 0 always
• Believing PageRequest.of needs 4 parameters

5. You want to fetch the third page of size 4, sorted by "price" descending and then by "name" ascending. Which Pageable creation is correct?

hard

A. PageRequest.of(2, 4, Sort.by("price", "name"))

B. PageRequest.of(3, 4, Sort.by("price").descending().and(Sort.by("name")))

C. PageRequest.of(2, 4, Sort.by(Sort.Order.desc("price"), Sort.Order.asc("name")))

D. PageRequest.of(2, 4, Sort.by("price").desc().and(Sort.by("name").asc()))

Solution

1. Step 1: Identify zero-based page index

   Third page means index 2 (0,1,2).

2. Step 2: Create Sort with multiple orders

   Use Sort.by(Order.desc("price"), Order.asc("name")) to combine sorting directions.

3. Step 3: Check syntax correctness

   PageRequest.of(2, 4, Sort.by(Sort.Order.desc("price"), Sort.Order.asc("name"))) uses correct PageRequest.of and Sort.by with orders.

4. Final Answer:

   PageRequest.of(2, 4, Sort.by(Sort.Order.desc("price"), Sort.Order.asc("name"))) -> Option C

5. Quick Check:

   Page 2 + size 4 + multi-sort orders correct [OK]

Hint: Use Sort.Order for multi-direction sorting [OK]

Common Mistakes:

• Using page number 3 instead of index 2
• Trying to chain .desc() or .asc() methods that don't exist
• Passing multiple fields without specifying order