In this tutorial, we will learn how to implement Sorting by multiple fields using Spring Data JPA.
To use paging and sorting APIs provided by Spring Data JPA, your repository interface must extend the
PagingAndSortingRepository
interface.
For sorting, we are going to use the below method from the PagingAndSortingRepository
interface:
Iterable < T > findAll(Sort sort);
Note: Spring Data JPA has SimpleJPARepository
class which implements
PagingAndSortingRepository
interface methods so we don't have to write code
to implement
PagingAndSortingRepository
interface methods.
Let's create a Spring boot project from the scratch and let's implement sorting with multiple fields using Spring Data JPA.
Spring Boot provides a web tool called https://start.spring.io to bootstrap an application quickly. Just go to https://start.spring.io and generate a new Spring Boot project.
Use the below details in the Spring Boot creation:
Here is the complete pom.xml
for your reference:
<?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 https://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>3.0.4</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>net.javaguides</groupId>
<artifactId>spring-data-jpa-course</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>spring-data-jpa-course</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>17</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>com.mysql</groupId>
<artifactId>mysql-connector-j</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
Let's use the MySQL database to store and retrieve the data in this example and we will use Hibernate properties to create and drop tables.
Open the application.properties
file and add the following configuration to
it:
spring.datasource.url=jdbc:mysql://localhost:3306/demo?useSSL=false
spring.datasource.username=root
spring.datasource.password=Mysql@123
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQLDialect
spring.jpa.hibernate.ddl-auto = create-drop
Make sure that you create a demo database before running the Spring Boot application.
Also, change the MySQL username and password as per your MySQL installation on your machine.
Let's create an entity
package inside the base package
net.javaguides.springboot.
Within the entity
package, create a Product
class with the following content:
import lombok.*;
import org.hibernate.annotations.CreationTimestamp;
import org.hibernate.annotations.UpdateTimestamp;
import jakarta.persistence.*;
import java.math.BigDecimal;
import java.time.LocalDateTime;
@Entity
@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
@ToString
@Table(
name = "products",
schema = "ecommerce",
uniqueConstraints = {
@UniqueConstraint(
name = "sku_unique",
columnNames = "stock_keeping_unit"
)
}
)
public class Product {
@Id
@GeneratedValue(
strategy = GenerationType.SEQUENCE,
generator = "product_generator"
)
@SequenceGenerator(
name = "product_generator",
sequenceName = "product_sequence_name",
allocationSize = 1
)
private Long id;
@Column(name = "stock_keeping_unit", nullable = false)
private String sku;
@Column(nullable = false)
private String name;
private String description;
private BigDecimal price;
private boolean active;
private String imageUrl;
@CreationTimestamp
private LocalDateTime dateCreated;
@UpdateTimestamp
private LocalDateTime lastUpdated;
}
Note that we are using Lombok annotations to reduce the boilerplate code.
The next thing we’re going to do is to create a repository to access Product
entity data from
the
database.
The JpaRepository
interface defines methods for all the CRUD operations on
the entity, and a
default
implementation of the JpaRepository
called SimpleJpaRepository
.
Let's create a repository package inside the base package net.javaguides.springdatarest.
Within the repository
package, create a ProductRepository
interface with the following content:
import com.springdatajpa.springboot.entity.Product;
import org.springframework.data.jpa.repository.JpaRepository;
public interface ProductRepository extends JpaRepository
{
}
Let's write the JUnit test and within the JUnit test, we will write a logic to implement sorting using Spring
import com.springdatajpa.springboot.entity.Product;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.data.domain.Sort;
import java.util.List;
@SpringBootTest
public class PaginationAndSortingTest {
@Autowired
private ProductRepository productRepository;
@Test
void sortingByMultipleFields(){
String sortBy = "name";
String sortByDesc = "description";
String sortDir = "desc";
Sort sortByName = sortDir.equalsIgnoreCase(Sort.Direction.ASC.name())?
Sort.by(sortBy).ascending(): Sort.by(sortBy).descending();
Sort sortByDescription = sortDir.equalsIgnoreCase(Sort.Direction.ASC.name())?
Sort.by(sortByDesc).ascending(): Sort.by(sortByDesc).descending();
Sort groupBySort = sortByName.and(sortByDescription);
List products = productRepository.findAll(groupBySort);
products.forEach((p) ->{
System.out.println(p);
});
}
}
If we wish to apply to sort on multiple columns or group by sort, then that is also possible by creating Sort using simple builder pattern steps:
String sortBy = "name";
String sortByDesc = "description";
String sortDir = "desc";
Sort sortByName = sortDir.equalsIgnoreCase(Sort.Direction.ASC.name())?
Sort.by(sortBy).ascending(): Sort.by(sortBy).descending();
Sort sortByDescription = sortDir.equalsIgnoreCase(Sort.Direction.ASC.name())?
Sort.by(sortByDesc).ascending(): Sort.by(sortByDesc).descending();
Sort groupBySort = sortByName.and(sortByDescription);
Once you run the JUnit test, you will get the below output:
Note that Spring Data JPA behind scenes uses Hibernate to generate the below SQL query for sorting:
select
product0_.id as id1_0_,
product0_.active as active2_0_,
product0_.date_created as date_cre3_0_,
product0_.description as descript4_0_,
product0_.image_url as image_ur5_0_,
product0_.last_updated as last_upd6_0_,
product0_.name as name7_0_,
product0_.price as price8_0_,
product0_.stock_keeping_unit as stock_ke9_0_
from
products product0_
order by
product0_.name desc,
product0_.description desc