Spring Boot Pagination Sorting

In this tutorial will demonstrate how to use pagination and sorting in spring boot application.

Page vs Slice

According to the Spring Data JPA documentation, Page extends Slice and knows the total number of items and pages available by initiating a count query.

A Page is aware of the entire number of elements and pages that are available. It achieves this by invoking a count query to calculate the total number. Because this may be costly depending on the business, Slice can be used as a return option. A Slice merely knows whether there is a next Slice available, which may be adequate for traversing a bigger result set.

Now, let's create the Spring Boot Project from Spring Initializer site https://start.spring.io/.

Refer Spring Data JPA documentation for Paging and Sorting for more details.

Project Structure

Maven Dependency

Add spring-boot-starter-data-jpa for jpa repository and spring-boot-starter-web for rest api's.

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.3.4.RELEASE</version>
		<relativePath /> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.techgeekenxt</groupId>
	<artifactId>spring-boot-pagination-sorting</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>spring-boot-pagination-sorting</name>
	<description>Spring Boot Pagination Sorting Example</description>

	<properties>
		<java.version>1.8</java.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-data-jpa</artifactId>
		</dependency>
		<dependency>
			<groupId>org.projectlombok</groupId>
			<artifactId>lombok</artifactId>
			<optional>true</optional>
		</dependency>
		<dependency>
			<groupId>com.h2database</groupId>
			<artifactId>h2</artifactId>
			<scope>runtime</scope>
		</dependency>
	</dependencies>
</project>

User JPA Entity

Create User entity class which represent user records in database.

package com.techgeeknext.model;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import javax.persistence.*;

@Data
@AllArgsConstructor
@NoArgsConstructor
@Entity
@Table(name="USERS")
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(name="first_name")
    private String firstName;

    @Column(name="last_name")
    private String lastName;

    @Column(name="status", nullable=false, length=200)
    private String status;
}

Repository

PagingAndSortingRepository interface extends CrudRepository for retrieving entities,it provides methods such as count , delete , deleteAll , deleteById , existsById , findAll , findAllById , findById , save , saveAll.

package com.techgeeknext.repository;

import com.techgeeknext.model.User;
import org.springframework.data.repository.PagingAndSortingRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface UserRepository
        extends PagingAndSortingRepository<User, Long> {

}

The act of loading one page of objects after another from a database in order to save resources is known as Paging.

Pagination is a user interface element that displays a list of page numbers to allow the user to select which page to load next.

User Service Class for Pagination and Sorting

Use findAll() method to do pagination and sorting.

package com.techgeeknext.service;

import com.techgeeknext.exception.UserNotFoundException;
import com.techgeeknext.model.User;
import com.techgeeknext.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.List;
import java.util.Optional;

@Service
public class UserService {

    @Autowired
    UserRepository userRepository;

    public List<User> getAllUsers(Integer pageNo, Integer pageSize, String sortBy) {
        Pageable paging = PageRequest.of(pageNo, pageSize, Sort.by(sortBy));

        Page<User> pagedResult = userRepository.findAll(paging);

        if (pagedResult.hasContent()) {
            return pagedResult.getContent();
        } else {
            return new ArrayList<User>();
        }
    }

    public User getUserById(Long id) throws UserNotFoundException {
        Optional<User> user = userRepository.findById(id);

        if (user.isPresent()) {
            return user.get();
        } else {
            throw new UserNotFoundException("User does not exist for given id.");
        }
    }

    public User createOrUpdateUser(User user2) throws UserNotFoundException {
        Optional<User> user = userRepository.findById(user2.getId());

        if (user.isPresent()) {
            User user1 = user.get();
            user1.setStatus(user2.getStatus());
            user1.setFirstName(user2.getFirstName());
            user1.setLastName(user2.getLastName());

            return userRepository.save(user1);
        } else {
            return userRepository.save(user2);
        }
    }

    public void deleteUserById(Long id) throws UserNotFoundException {
        if (userRepository.findById(id).isPresent()) {
            userRepository.deleteById(id);
        } else {
            throw new UserNotFoundException("User does not exist for given id.");
        }
    }
}

Test Pagination and Sorting

1. Start the Spring Boot application by using mvn spring-boot run command and use rest endpoint to get all users : http://localhost:8282/users .
2. Use rest endpoint to get data with page size : http://localhost:8282/users?pageSize=1 .
3. http://localhost:8282/users?pageSize=7&pageNo=2
4. http://localhost:8282/users?pageSize=7&pageNo=2&sortBy=status

Download Source Code

The full source code for this article can be found on below.
Download it here - Spring Boot Pagination Sorting Example