Pagination is a common feature in web applications. It is used to break down large data sets into smaller, more manageable chunks. Spring Boot makes it easy to implement pagination in a web application.
In this post, we will learn how to implement pagination in a Spring Boot application. We will start by creating a simple Spring Boot application. Then, we will add the pagination feature to the application.
Creating a Spring Boot application
We will use the Spring Initializr to create our Spring Boot application. Go to the Spring Initializr website and select the following options:
Click on the "Generate" button to generate the project.
Once the project is generated, import it into your favorite IDE. I am using Eclipse.
Adding the pagination feature
We will use the Pageable interface from the org.springframework.data.domain package to implement pagination in our application.
First, we need to add the spring-data-commons dependency to our pom.xml file:
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-commons</artifactId>
<version>2.1.3.RELEASE</version>
</dependency>
Next, we will create a simple RestController with a method that returns a list of users:
@RestController
public class UserController {
@GetMapping("/users")
public List<User> getUsers() {
// Return a list of users
}
}
Now, we will add the pagination feature to the getUsers() method. We will use the Pageable interface to specify the page size and the page number. The Pageable interface has two implementations: PageRequest and Slice. We will use the PageRequest implementation in our example.
@GetMapping("/users")
public List<User> getUsers(Pageable pageable) {
// Return a list of users
}
We can also specify the page size and the page number as query parameters:
@GetMapping("/users")
public List<User> getUsers(
@RequestParam(name = "page", defaultValue = "0") int page,
@RequestParam(name = "size", defaultValue = "10") int size) {
// Return a list of users
}
In the above example, we have specified that the default page size is 10 and the default page number is 0.
Testing the pagination feature
We can test the pagination feature by sending a GET request to the /users endpoint with the page and size query parameters.
For example, the following request will return the first page of users with a page size of 10:
GET /users?page=0&size=10
The following request will return the second page of users with a page size of 10:
GET /users?page=1&size=10
And so on.
Additional Information
The Pageable interface has several other methods that can be used to customize the pagination behavior. For more information, please see the JavaDocs for the Pageable interface.
Warnings
When implementing pagination, it is important to ensure that the page size is not too large. If the page size is too large, it can result in OutOfMemoryErrors.
Dangers
When implementing pagination, it is important to ensure that the page size is not too small. If the page size is too small, it can result in too many database queries.