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Hey guys in this post, we will discuss Data JPA @NamedQuery annotation with Example. We will create a spring boot project step by step and connect it to the MySQL database. This is the continuation of the previous post, please follow that post, before proceeding with this.

Complete example

Let’s create a step-by-step spring boot project and create a native query in Data JPA.

Read More:

• Check the complete Spring Boot Data JPA Tutorials

Create spring boot project

There are many different ways to create a spring boot application, you can follow the below articles to create one –

>> Create spring boot application using Spring initializer
>> Create spring boot application in Spring tool suite [STS]
>> Create spring boot application in IntelliJ IDEA

Add maven dependencies

Open pom.xml and add the following dependencies –

<?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>2.4.4</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>in.bushansirgur</groupId>
	<artifactId>findbyfieldname</artifactId>
	<version>v1</version>
	<name>findbyfieldname</name>
	<description>Spring boot data jpa find by field name</description>
	<properties>
		<java.version>1.8</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>org.springframework.boot</groupId>
			<artifactId>spring-boot-devtools</artifactId>
			<scope>runtime</scope>
			<optional>true</optional>
		</dependency>
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</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>

spring-boot-starter-web dependency for building web applications using Spring MVC. It uses the tomcat as the default embedded container.

spring-boot-devtools dependency for automatic reloads or live reload of applications. spring-boot-starter-data-jpa dependency is a starter for using Spring Data JPA with Hibernate. lombok dependency is a java library that will reduce the boilerplate code that we usually write inside every entity class like setters, getters, and toString()

Configure the datasource

spring.datasource.url=jdbc:mysql://localhost:3306/mydb
spring.datasource.username=scbushan05
spring.datasource.password=scbushan05

spring.jpa.hibernate.ddl-auto=update

Create an entity class

Create Laptop.java inside the in.bushansirgur.springboot.entity package and add the following content

package in.bushansirgur.springboot.entity;

import java.math.BigDecimal;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.NamedQuery;
import javax.persistence.Table;

import in.bushansirgur.springboot.request.LaptopRequest;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;

@Entity
@Table(name="tbl_laptops")
@Getter
@Setter
@NoArgsConstructor
@NamedQuery(name = "Laptop.getAllRecords", query = "FROM Laptop WHERE name = ?1")
public class Laptop {
	
	@Id
	@GeneratedValue(strategy = GenerationType.IDENTITY)
	private Long id;
	
	private String name;
	
	private String brand;
	
	private BigDecimal price;
	
	public Laptop(LaptopRequest request) {
		this.name = request.getName();
		this.price = request.getPrice();
		this.brand = request.getBrand();
	}
	
}

• @NamedQuery annotation is used to write the SQL query. We write the JPQL query inside this annotation. The option name is used the specify the name of the method, the option query is used to write the JPQL query.
• @Data annotation which is a Lombok annotation, that will automatically create setters, getters, toString(), and equals() for us.
• @Entity is a mandatory annotation that indicates that this class is a JPA entity and is mapped with a database table.
• @Table annotation is an optional annotation that contains the table info like table name.

• @Id annotation is a mandatory annotation that marks a field as the primary key

Create a Repository

Create an interface LaptopRepository.java inside the in.bushansirgur.springboot.repos package and add the following content

package in.bushansirgur.springboot.repository;

import java.util.List;

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

import in.bushansirgur.springboot.entity.Laptop;

@Repository
public interface LaptopRepository extends JpaRepository<Laptop, Long>{

	List<Laptop> getAllRecords (String name); 
	
}

Inside the repository, we need to create a method with the same name that we have given in the @NamedQuery annotation.

Create a Rest controller

Create LaptopController.java inside the in.bushansirgur.springboot.controller package and add the following content

package in.bushansirgur.springboot.controller;

import java.util.List;

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

import in.bushansirgur.springboot.entity.Laptop;
import in.bushansirgur.springboot.repository.LaptopRepository;

@RestController
public class LaptopController {
	
	@Autowired
	private LaptopRepository lRepo;
	
	@PostMapping("/laptops/save")
	public Laptop saveData (@RequestBody Laptop laptop) {
		return lRepo.save(laptop);
		
	}
	
	@GetMapping("/laptops/{name}")
	public List<Laptop> readData (@PathVariable String name) {
		return lRepo.getAllRecords(name); 
		
	}
}

Run the app

Run the application using the below maven command –

mvn spring-boot:run

Open the browser and enter the following URL –

• localhost:8080/laptops/macbook air

That’s it for this post, I hope you guys enjoyed this post. If you did, please share this post with your friends and colleagues. Also, share this post on your social media profile. Thanks, I will see you in the next post.