Use Less Than in JPA Repository

Last updated on October 5th, 2024

In the JPA Repository, we can easily perform comparison operations such as “less than” using the query method with the LessThan keyword and < operator with JPQL and Native SQL query. In this topic, we will learn how to use less than in the JPA Repository using these various methods.

Use Less Than in JPA Repository

1. Query Method with LessThan Keyword

Add a custom query method in the repository interface with the findBy keyword then put the field name then add a suffix with the LessThan keyword and add parameter [findByField_NameLessThan(Parameter param)].

Example

import java.util.List;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.Query;

public interface OrderRepository extends JpaRepository<OrderDetail, Long> {
List<OrderDetail> findByAmountLessThan(Double amount);
}

2. JPQL with Less than operator(<)

Add a custom method and use @Query annotation to specify less than the query using JPQL in the repository interface.

Example

import java.util.List;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.Query;

public interface OrderRepository extends JpaRepository<OrderDetail, Long> {
@Query("SELECT o FROM OrderDetail o WHERE o.amount < :amount")
List<OrderDetail> findOrdersWithAmountLessThan(Double amount);
}

3. Native SQL with Less than operator(<)

Add a custom method and use @Query annotation with nativeQuery attribute to specify less than the query using native SQL in the repository interface.

Example

import java.util.List;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.Query;

public interface OrderRepository extends JpaRepository<OrderDetail, Long> {
@Query(value = "SELECT * FROM order_detail WHERE amount < :amount", nativeQuery = true)
List<OrderDetail> findOrdersWithNativeQuery(Double amount);
}

Step-by-step to Guide the Use Less Than in JPA Repository

Let’s make a Spring Boot Application step-by-step guide to use Less Than in JPA to fetch records from the database table. We will create an example to provide list of orders where the amount is less than the specified value using API endpoints through the methods mentioned above.

These are the following steps:

Create a Spring Boot Project
Setup in the IDE
Configure H2 Database
Create a JPA Entity
Create a Repository Interface
Create a Service Interface
Implement the Service Interface
Create a Controller
Run the Spring Boot Application

1. Create a Spring Boot Project

We are creating a Spring Boot Project from the web tool Spring Initializr. By Providing details for the project and select the following Maven dependencies:

Spring Web
Spring Data JPA
H2 Database
Lombok

2. Setup in the IDE

We use Eclipse IDE to set up and configure the created Spring Boot Project. You can use other IDE to set up and configure the Spring Boot project.

Project Structure of Spring Boot

This image shows the project structure of Spring Boot in Eclipse IDE.

Maven Dependency

Here is the complete maven dependencies file pom.xml for the project which will implement methods to use Less Than in JPA Repository.

pom.xml

<?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>3.3.0</version>
		<relativePath/>
		<!-- lookup parent from repository -->
	</parent>
	<groupId>com.springjava</groupId>
	<artifactId>demo</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>demo</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>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		<dependency>
			<groupId>com.h2database</groupId>
			<artifactId>h2</artifactId>
			<scope>runtime</scope>
		</dependency>
		<dependency>
			<groupId>org.projectlombok</groupId>
			<artifactId>lombok</artifactId>
			<optional>true</optional>
		</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>
				<configuration>
					<excludes>
						<exclude>
							<groupId>org.projectlombok</groupId>
							<artifactId>lombok</artifactId>
						</exclude>
					</excludes>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

3. Configure H2 Database

We are going to configure the H2 database connection in the application.properties file.

application.properties

# H2 Database Configuration
spring.datasource.url=jdbc:h2:mem:test
spring.datasource.username=sa
spring.datasource.password=
spring.jpa.show-sql=true
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.H2Dialect
spring.jpa.hibernate.ddl-auto=update
spring.h2.console.enabled=true

4. Create a JPA Entity

Let’s create a JPA Entity class. For example, consider an OrderDetail entity and use Lombok for generating setter and getter methods, a constructor, etc.

OrderDetail.java

package com.springjava.entity;

import jakarta.persistence.Entity;

import jakarta.persistence.GeneratedValue;

import jakarta.persistence.GenerationType;

import jakarta.persistence.Id;

import lombok.Data;

@Data

@Entity

public class OrderDetail {

  @Id

  @GeneratedValue(strategy = GenerationType.IDENTITY)

  private Long id;

  private Long customerId;

  private Double amount;

}

5. Create a Repository Interface

Create a repository interface for the OrderDetail JPA Entity class that interface extends the JpaRepository interface to perform persistence operations on the order_detail database table.

OrderRepository.java

package com.springjava.repository;

import java.util.List;

import org.springframework.data.jpa.repository.JpaRepository;

import org.springframework.data.jpa.repository.Query;

import com.springjava.entity.OrderDetail;

public interface OrderRepository extends JpaRepository < OrderDetail, Long > {

  List < OrderDetail > findByAmountLessThan(Double amount);

  @Query("SELECT o FROM OrderDetail o WHERE o.amount < :amount")

  List < OrderDetail > findOrdersWithAmountLessThan(Double amount);

  @Query(value = "SELECT * FROM order_detail WHERE amount < :amount", nativeQuery = true)

  List < OrderDetail > findOrdersWithNativeQuery(Double amount);

}

6. Create a Service Interface

Create a Service interface OrderService with some method declaration.

OrderService.java

package com.springjava.service;

import java.util.List;

import com.springjava.entity.OrderDetail;

public interface OrderService {

  void saveAll(List < OrderDetail > orderList);

  List < OrderDetail > getOrderByAmountLessThan(Double amount);

  List < OrderDetail > getOrderByAmountLessThanWithJPQL(Double amount);

  List < OrderDetail > getOrderByAmountLessThanWithNative(Double amount);

}

7. Implement the Service Interface

Implement the OrderService interface in the OrderServiceImpl class. This class is annotated with @Service annotation, where we inject OrderRepository to call all its methods.

OrderServiceImpl.java

package com.springjava.service;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Service;

import com.springjava.entity.OrderDetail;

import com.springjava.repository.OrderRepository;

@Service

public class OrderServiceImpl implements OrderService {

@Autowired

private OrderRepository orderRepo;

@Override

public void saveAll(List<OrderDetail> orderList) {

orderRepo.saveAll(orderList);

}

@Override

public List<OrderDetail> getOrderByAmountLessThan(Double amount) {

return orderRepo.findByAmountLessThan(amount);

}

@Override

public List<OrderDetail> getOrderByAmountLessThanWithJPQL(Double amount) {

return orderRepo.findOrdersWithAmountLessThan(amount);

}

@Override

public List<OrderDetail> getOrderByAmountLessThanWithNative(Double amount) {

return orderRepo.findOrdersWithNativeQuery(amount);

}

}

8. Create a Controller

Create a controller class OrderController. This is annotated with @RestController to make this class a RestController.

OrderController.java

package com.springjava.controller;

import java.util.LinkedHashMap;

import java.util.List;

import java.util.Map;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.http.HttpStatus;

import org.springframework.http.ResponseEntity;

import org.springframework.web.bind.annotation.GetMapping;

import org.springframework.web.bind.annotation.PathVariable;

import org.springframework.web.bind.annotation.PostMapping;

import org.springframework.web.bind.annotation.RequestBody;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RestController;

import com.springjava.entity.OrderDetail;

import com.springjava.service.OrderService;

@RestController

@RequestMapping("/api/order")

public class OrderController {

  @Autowired

  private OrderService orderService;

  @PostMapping("/save-all")

  public ResponseEntity < ? > save(@RequestBody List < OrderDetail > orderList) {

    Map < String, Object > respOrder = new LinkedHashMap < String, Object > ();

    orderService.saveAll(orderList);

    respOrder.put("status", 1);

    respOrder.put("message", "Record is Saved Successfully!");

    return new ResponseEntity < > (respOrder, HttpStatus.CREATED);

  }

  @GetMapping("/less-than-query-method/{amount}")

  public ResponseEntity < ? > getOrdersByAmtLessThan(@PathVariable Double amount) {

    Map < String, Object > respOrder = new LinkedHashMap < String, Object > ();

    List < OrderDetail > orderList = orderService.getOrderByAmountLessThan(amount);

    if (!orderList.isEmpty()) {

      respOrder.put("status", 1);

      respOrder.put("data", orderList);

      return new ResponseEntity < > (respOrder, HttpStatus.OK);

    } else {

      respOrder.clear();

      respOrder.put("status", 0);

      respOrder.put("message", "Data is not found");

      return new ResponseEntity < > (respOrder, HttpStatus.NOT_FOUND);

    }

  }

  @GetMapping("/less-than-jpql/{amount}")

  public ResponseEntity < ? > getOrdersByAmtLessThanJPQL(@PathVariable Double amount) {

    Map < String, Object > respOrder = new LinkedHashMap < String, Object > ();

    List < OrderDetail > orderList = orderService.getOrderByAmountLessThanWithJPQL(amount);

    if (!orderList.isEmpty()) {

      respOrder.put("status", 1);

      respOrder.put("data", orderList);

      return new ResponseEntity < > (respOrder, HttpStatus.OK);

    } else {

      respOrder.clear();

      respOrder.put("status", 0);

      respOrder.put("message", "Data is not found");

      return new ResponseEntity < > (respOrder, HttpStatus.NOT_FOUND);

    }

  }

  @GetMapping("/less-than-native/{amount}")

  public ResponseEntity < ? > getOrdersByAmtLessThanNative(@PathVariable Double amount) {

    Map < String, Object > respOrder = new LinkedHashMap < String, Object > ();

    List < OrderDetail > orderList = orderService.getOrderByAmountLessThanWithNative(amount);

    if (!orderList.isEmpty()) {

      respOrder.put("status", 1);

      respOrder.put("data", orderList);

      return new ResponseEntity < > (respOrder, HttpStatus.OK);

    } else {

      respOrder.clear();

      respOrder.put("status", 0);

      respOrder.put("message", "Data is not found");

      return new ResponseEntity < > (respOrder, HttpStatus.NOT_FOUND);

    }

  }

}

9. Run the Spring Boot Application

Right-click this Spring Boot application on the DemoApplication.java, then click Run As and select Java Application.

H2 Database Console

To check the H2 database console use the URL http://localhost:[server_port]/h2-console.

JSON Array

We are creating a sample JSON Array to test the API http://localhost:8080/api/order/save-all.

[{
"customerId": 1,
"amount": 700
},
{
"customerId": 1,
"amount": 800
}, 
{
"customerId": 2,
"amount": 900
},
{
"customerId": 3,
"amount": 800
}]

Test the APIs on the Postman Tool

POST: http://localhost:8080/api/order/save-all

GET: http://localhost:8080/api/order/less-than-query-method/800

This API hits then Spring Data JPA (internally uses Hibernate as a JPA provider) generates SQL statement in the console below here:

Hibernate: select od1_0.id,od1_0.amount,od1_0.customer_id from order_detail od1_0 where od1_0.amount<?

GET: http://localhost:8080/api/order/less-than-jpql/800

This API hits then Spring Data JPA (internally uses Hibernate as a JPA provider) generates SQL statement in the console below here:

Hibernate: select od1_0.id,od1_0.amount,od1_0.customer_id from order_detail od1_0 where od1_0.amount<?

GET: http://localhost:8080/api/order/less-than-native/800

This API hits then Spring Data JPA (internally uses Hibernate as a JPA provider) generates SQL statement in the console below here:

Hibernate: SELECT * FROM order_detail WHERE amount < ?

Conclusion

Less Than is used in the JPA Repository through query method with LessThan keyword, JPQL and Native SQL query with (<) operator.

Use Less Than in JPA Repository

1. Query Method with LessThan Keyword

2. JPQL with Less than operator(<)

3. Native SQL with Less than operator(<)

Step-by-step to Guide the Use Less Than in JPA Repository

1. Create a Spring Boot Project

2. Setup in the IDE

Project Structure of Spring Boot

Maven Dependency

3. Configure H2 Database

4. Create a JPA Entity

5. Create a Repository Interface

6. Create a Service Interface

7. Implement the Service Interface

8. Create a Controller

9. Run the Spring Boot Application

H2 Database Console

JSON Array

Test the APIs on the Postman Tool

Conclusion

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