postgresql-crud-02

Description

We’re gonna build a Spring Boot WebFlux Rest API example – CRUD application that uses Spring Data Reactive (R2DBC) to interact with embedded database.

Requirements

• Java 17+
• Spring Boot 3.0.2
• PostgreSQL
• Maven 3.6+

Database

docker run -it --rm \
    -p 5432:5432 \
    -e POSTGRES_USER=dbuser \
    -e POSTGRES_PASSWORD=theSecretPassword \
    -e POSTGRES_DB=micronaut \
    postgres:11.5-alpine

Project Structure

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>3.0.2</version>
		<relativePath /> <!-- lookup parent from repository -->
	</parent>

	<groupId>zjc.examples</groupId>
	<artifactId>spring-webflux-postgresql-crud-02</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>spring-webflux-postgresql-crud-02</name>
	<description>spring-webflux-postgresql-crud-02</description>

	<properties>
		<java.version>17</java.version>
	</properties>
	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-data-r2dbc</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-webflux</artifactId>
		</dependency>

		<dependency>
			<groupId>org.postgresql</groupId>
			<artifactId>postgresql</artifactId>
			<scope>runtime</scope>
		</dependency>

		<dependency>
			<groupId>org.postgresql</groupId>
			<artifactId>r2dbc-postgresql</artifactId>
			<scope>runtime</scope>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>

		<dependency>
			<groupId>io.projectreactor</groupId>
			<artifactId>reactor-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>

application.properties

spring.r2dbc.url=r2dbc:postgresql://localhost:5432/micronaut
spring.r2dbc.username=dbuser
spring.r2dbc.password=theSecretPassword

schema.sql

CREATE TABLE IF NOT EXISTS tutorial (id SERIAL PRIMARY KEY, title VARCHAR(255), description VARCHAR(255), published BOOLEAN);

Enable r2dbc Repositories

@EnableR2dbcRepositories is a Spring annotation that is used to enable R2DBC repositories in a Spring Boot application. It provides a convenient way to create a repository layer in a Spring Boot application that uses R2DBC to interact with a database.

Because R2DBC repository support is enabled in our Spring Boot application by default (spring.data.r2dbc.repositories.enabled=true), so that the @EnableR2dbcRepositories is not necessary.

The @EnableR2dbcRepositories annotation could be added to a configuration class in your application, typically the main class that is annotated with @SpringBootApplication:

SpringBootR2dbcPostgresqlExampleApplication.java

package zjc.examples.spring.r2dbc.postgresql;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.core.io.ClassPathResource;
//import org.springframework.data.r2dbc.repository.config.EnableR2dbcRepositories;
import org.springframework.r2dbc.connection.init.ConnectionFactoryInitializer;
import org.springframework.r2dbc.connection.init.ResourceDatabasePopulator;
import org.springframework.web.reactive.config.EnableWebFlux;

import io.r2dbc.spi.ConnectionFactory;

@EnableWebFlux
//@EnableR2dbcRepositories
@SpringBootApplication
public class SpringBootR2dbcPostgresqlExampleApplication {

  @Bean
  ConnectionFactoryInitializer initializer(ConnectionFactory connectionFactory) {

    ConnectionFactoryInitializer initializer = new ConnectionFactoryInitializer();
    initializer.setConnectionFactory(connectionFactory);
    initializer.setDatabasePopulator(new ResourceDatabasePopulator(new ClassPathResource("schema.sql")));

    return initializer;
  }

  public static void main(String[] args) {
    SpringApplication.run(SpringBootR2dbcPostgresqlExampleApplication.class, args);
  }

}

TutorialRepository.java

package zjc.examples.spring.r2dbc.postgresql.repository;

import org.springframework.data.r2dbc.repository.R2dbcRepository;
import org.springframework.stereotype.Repository;

import zjc.examples.spring.r2dbc.postgresql.model.Tutorial;

import reactor.core.publisher.Flux;

@Repository
public interface TutorialRepository extends R2dbcRepository<Tutorial, Integer>{
  Flux<Tutorial> findByTitleContaining(String title);

  Flux<Tutorial> findByPublished(boolean isPublished);
}

Tutorial.java (Data Model)

package zjc.examples.spring.r2dbc.postgresql.model;

import org.springframework.data.annotation.Id;

public class Tutorial {

  @Id
  private int id;

  private String title;

  private String description;

  private boolean published;

  public Tutorial() {

  }

  public Tutorial(String title, String description, boolean published) {
    this.title = title;
    this.description = description;
    this.published = published;
  }

  public void setId(int id) {
    this.id = id;
  }

  public long getId() {
    return id;
  }

  public String getTitle() {
    return title;
  }

  public void setTitle(String title) {
    this.title = title;
  }

  public String getDescription() {
    return description;
  }

  public void setDescription(String description) {
    this.description = description;
  }

  public boolean getPublished() {
    return published;
  }

  public void setPublished(boolean isPublished) {
    this.published = isPublished;
  }

  @Override
  public String toString() {
    return "Tutorial [id=" + id + ", title=" + title + ", desc=" + description + ", published=" + published + "]";
  }

}

TutorialService.java

package zjc.examples.spring.r2dbc.postgresql.service;

import java.util.Optional;

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

import zjc.examples.spring.r2dbc.postgresql.model.Tutorial;
import zjc.examples.spring.r2dbc.postgresql.repository.TutorialRepository;

import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

@Service
public class TutorialService {

  @Autowired
  TutorialRepository tutorialRepository;

  public Flux<Tutorial> findAll() {
    return tutorialRepository.findAll();
  }

  public Flux<Tutorial> findByTitleContaining(String title) {
    return tutorialRepository.findByTitleContaining(title);
  }

  public Mono<Tutorial> findById(int id) {
    return tutorialRepository.findById(id);
  }

  public Mono<Tutorial> save(Tutorial tutorial) {
    return tutorialRepository.save(tutorial);
  }

  public Mono<Tutorial> update(int id, Tutorial tutorial) {
    return tutorialRepository.findById(id).map(Optional::of).defaultIfEmpty(Optional.empty())
        .flatMap(optionalTutorial -> {
          if (optionalTutorial.isPresent()) {
            tutorial.setId(id);
            return tutorialRepository.save(tutorial);
          }

          return Mono.empty();
        });
  }

  public Mono<Void> deleteById(int id) {
    return tutorialRepository.deleteById(id);
  }

  public Mono<Void> deleteAll() {
    return tutorialRepository.deleteAll();
  }

  public Flux<Tutorial> findByPublished(boolean isPublished) {
    return tutorialRepository.findByPublished(isPublished);
  }
}

TutorialController.java (Spring WebFlux Rest API Controller)

package zjc.examples.spring.r2dbc.postgresql.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.bind.annotation.DeleteMapping;
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.PutMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseStatus;
import org.springframework.web.bind.annotation.RestController;

import zjc.examples.spring.r2dbc.postgresql.model.Tutorial;
import zjc.examples.spring.r2dbc.postgresql.service.TutorialService;

import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

@CrossOrigin(origins = "http://localhost:8081")
@RestController
@RequestMapping("/api")
public class TutorialController {
  @Autowired
  TutorialService tutorialService;

  @GetMapping("/tutorials")
  @ResponseStatus(HttpStatus.OK)
  public Flux<Tutorial> getAllTutorials(@RequestParam(required = false) String title) {
    if (title == null)
      return tutorialService.findAll();
    else
      return tutorialService.findByTitleContaining(title);
  }

  @GetMapping("/tutorials/{id}")
  @ResponseStatus(HttpStatus.OK)
  public Mono<Tutorial> getTutorialById(@PathVariable("id") int id) {
    return tutorialService.findById(id);
  }

  @PostMapping("/tutorials")
  @ResponseStatus(HttpStatus.CREATED)
  public Mono<Tutorial> createTutorial(@RequestBody Tutorial tutorial) {
    return tutorialService.save(new Tutorial(tutorial.getTitle(), tutorial.getDescription(), false));
  }

  @PutMapping("/tutorials/{id}")
  @ResponseStatus(HttpStatus.OK)
  public Mono<Tutorial> updateTutorial(@PathVariable("id") int id, @RequestBody Tutorial tutorial) {
    return tutorialService.update(id, tutorial);
  }

  @DeleteMapping("/tutorials/{id}")
  @ResponseStatus(HttpStatus.NO_CONTENT)
  public Mono<Void> deleteTutorial(@PathVariable("id") int id) {
    return tutorialService.deleteById(id);
  }

  @DeleteMapping("/tutorials")
  @ResponseStatus(HttpStatus.NO_CONTENT)
  public Mono<Void> deleteAllTutorials() {
    return tutorialService.deleteAll();
  }

  @GetMapping("/tutorials/published")
  @ResponseStatus(HttpStatus.OK)
  public Flux<Tutorial> findByPublished() {
    return tutorialService.findByPublished(true);
  }
}

Running

Run Spring Boot application: mvn spring-boot:run

Postman. Create Tutorials:

Analogously:

• Read Operation,
• Update Operation,
• Delete Operation.

Source code:

https://github.com/ZbCiok/zjc-examples/tree/main/spring/webflux/spring-webflux-postgresql-crud-02