Create Spring Boot Project
On the Eclipse, create a Spring Boot project
Enter Project Information:
- Name: SpringBootDataJPA
- Group: com.demo
- Artifact: SpringBootDataJPA
- Description: Spring Boot Data JPA
- Package: com.demo
Select the technologies and libraries to be used:
- JPA
- MySQL
Click Next button to show Site Information for project
Click Finish button to finish create Spring Boot project
Configure 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 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>2.2.0.M1</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<groupId>com.demo</groupId>
<artifactId>SpringBootDataJPA</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>SpringBootDataJPA</name>
<description>Spring Boot Data JPA</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>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>net.bytebuddy</groupId>
<artifactId>byte-buddy</artifactId>
<version>1.9.12</version>
</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>
<repositories>
<repository>
<id>spring-snapshots</id>
<name>Spring Snapshots</name>
<url>https://repo.spring.io/snapshot</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</repository>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>spring-snapshots</id>
<name>Spring Snapshots</name>
<url>https://repo.spring.io/snapshot</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</pluginRepository>
<pluginRepository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
</pluginRepository>
</pluginRepositories>
</project>
Create Database
Create a database with the name is springbootdatajpa. This database have a table: Product
--
-- Table structure for table `product`
--
CREATE TABLE `product` (
`id` int(11) NOT NULL PRIMARY KEY AUTO_INCREMENT,
`name` varchar(250) COLLATE utf8_unicode_ci NOT NULL,
`price` decimal(10,1) NOT NULL,
`quantity` int(11) NOT NULL,
`description` text COLLATE utf8_unicode_ci NOT NULL,
`photo` varchar(250) COLLATE utf8_unicode_ci NOT NULL,
`featured` tinyint(1) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;
--
-- Dumping data for table `product`
--
INSERT INTO `product` (`name`, `price`, `quantity`, `description`, `photo`, `featured`) VALUES('Mobile 1', '2.0', 2, 'description 1', 'thumb1.gif', 0);
INSERT INTO `product` (`name`, `price`, `quantity`, `description`, `photo`, `featured`) VALUES('Mobile 2', '1.0', 5, 'description 2', 'thumb2.gif', 1);
INSERT INTO `product` (`name`, `price`, `quantity`, `description`, `photo`, `featured`) VALUES('Mobile 3', '3.0', 9, 'description 3', 'thumb3.gif', 0);
INSERT INTO `product` (`name`, `price`, `quantity`, `description`, `photo`, `featured`) VALUES('Computer 1', '5.0', 12, 'description 4', 'thumb1.gif', 1);
INSERT INTO `product` (`name`, `price`, `quantity`, `description`, `photo`, `featured`) VALUES('Computer 2', '7.0', 5, 'description 5', 'thumb1.gif', 0);
INSERT INTO `product` (`name`, `price`, `quantity`, `description`, `photo`, `featured`) VALUES('Computer 3', '12.0', 2, 'description 6', 'thumb2.gif', 1);
INSERT INTO `product` (`name`, `price`, `quantity`, `description`, `photo`, `featured`) VALUES('Laptop 1', '3.0', 8, 'description 7', 'thumb2.gif', 0);
INSERT INTO `product` (`name`, `price`, `quantity`, `description`, `photo`, `featured`) VALUES('Laptop 2', '4.0', 11, 'description 8', 'thumb3.gif', 1);
INSERT INTO `product` (`name`, `price`, `quantity`, `description`, `photo`, `featured`) VALUES('Laptop 3', '2.0', 15, 'description 9', 'thumb2.gif', 0);
Structure of Product Table
Data of Product Table
Database Configuration
Open application.properties file in src/main/resources folder and add configurations connect to database as below:
spring.datasource.url= jdbc:mysql://localhost:3306/springbootdatajpa
spring.datasource.username=root
spring.datasource.password=123456
Entities Class
Create new package named com.demo.entities. In this package, create new java class named Product.java as below:
package com.demo.entities;
import java.io.Serializable;
import java.math.BigDecimal;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
@Entity
@Table(name = "product")
public class Product implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
private String name;
private BigDecimal price;
private int quantity;
private String description;
private String photo;
private boolean featured;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public BigDecimal getPrice() {
return price;
}
public void setPrice(BigDecimal price) {
this.price = price;
}
public int getQuantity() {
return quantity;
}
public void setQuantity(int quantity) {
this.quantity = quantity;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public String getPhoto() {
return photo;
}
public void setPhoto(String photo) {
this.photo = photo;
}
public boolean isFeatured() {
return featured;
}
public void setFeatured(boolean featured) {
this.featured = featured;
}
}
ProductRepository Interface
Create new package named com.demo.repositories. In this package, create new interface named ProductRepository.java implement from CrudRepository interface of Spring Framework as below:
package com.demo.repositories;
import java.util.List;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.CrudRepository;
import org.springframework.data.repository.query.Param;
import org.springframework.stereotype.Repository;
import com.demo.entities.Product;
@Repository("productRepository")
public interface ProductRepository extends CrudRepository<Product, Integer> {
@Query(value = "SELECT * FROM product order by id desc limit :limit", nativeQuery = true)
public List<Product> findTopN(@Param("limit") int limit);
}
ProductService Interface
Create new package named com.demo.services. In this package create new interface named ProductService.java as below:
package com.demo.services;
import java.util.List;
import com.demo.entities.Product;
public interface ProductService {
public List<Product> findTopN(int n);
}
ProductServiceImpl Class
In com.demo.services package, create new java class named ProductServiceImpl.java implement from ProductService interface
package com.demo.services;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import com.demo.entities.Product;
import com.demo.repositories.ProductRepository;
@Transactional
@Service("productService")
public class ProductServiceImpl implements ProductService {
@Autowired
private ProductRepository productRepository;
@Override
public List<Product> findTopN(int n) {
return productRepository.findTopN(n);
}
}
JPA Configuration
In com.demo package, create new java class named JPAConfiguration.java as below:
package com.demo;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import com.demo.services.ProductService;
import com.demo.services.ProductServiceImpl;
@Configuration
@EnableAutoConfiguration
@EnableTransactionManagement
@EnableJpaRepositories(basePackages = { "com.demo.repositories" })
@ComponentScan("com.demo")
@PropertySource("classpath:application.properties")
public class JPAConfiguration {
@Bean
public ProductService productService() {
return new ProductServiceImpl();
}
}
Project Structure
Application
Create new package named com.demo.main. In this package, create new java file named Demo.java as below:
package com.demo.main;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.support.AbstractApplicationContext;
import com.demo.entities.Product;
import com.demo.JPAConfiguration;
import com.demo.services.ProductService;
public class Demo {
public static void main(String[] args) {
try {
AbstractApplicationContext context = new AnnotationConfigApplicationContext(JPAConfiguration.class);
ProductService productService = context.getBean(ProductService.class);
for (Product product : productService.findTopN(3)) {
System.out.println("Id: " + product.getId());
System.out.println("Name: " + product.getName());
System.out.println("Price: " + product.getPrice());
System.out.println("========================");
}
context.close();
} catch (Exception e) {
System.out.println(e.getMessage());
}
}
}
Output
Id: 13
Name: Laptop 3
Price: 2.0
========================
Id: 12
Name: Laptop 2
Price: 4.0
========================
Id: 7
Name: Laptop 1
Price: 3.0
========================