Reactive CRUD APIs with Spring WebFlux

Application.properties

logging.level.org.springframework=ERROR
#logging.level.org.springframework=TRACE
logging.level.com=TRACE
server.port=8080  
spring.data.mongodb.host=localhost
spring.data.mongodb.port=27017
spring.data.mongodb.database=testdb

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>2.2.2.RELEASE</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.reactiveCRUD</groupId>
	<artifactId>universityApp</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>universityApp</name>
	<description>SpringFlux Restful CRUD example</description>

	<properties>
		<java.version>1.8</java.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-data-mongodb-reactive</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-webflux</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-devtools</artifactId>
			<scope>runtime</scope>
			<optional>true</optional>
		</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>
			<exclusions>
				<exclusion>
					<groupId>org.junit.vintage</groupId>
					<artifactId>junit-vintage-engine</artifactId>
				</exclusion>
			</exclusions>
		</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>

RegistrationController.java

package com.reactiveCRUD.universityApp.controller;

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

import com.reactiveCRUD.universityApp.model.Student;
import com.reactiveCRUD.universityApp.service.RegistrationService;

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

@RequestMapping("adminDept")
@AllArgsConstructor
@RestController
public class RegistrationController {
	
	@Autowired
	private RegistrationService registrationService;

	@GetMapping
	public Flux<Student> getAll() {
		System.out.println("::will returns ALL Students records::");
		return registrationService.getAll();
	}
	
	
	@GetMapping("{id}")
	public Mono<Student> getById(@PathVariable("id") final String id) {
		System.out.println("::will return a Student record::");
		return registrationService.getById(id);
	}

	@PutMapping("{id}")
	public Mono updateById(@PathVariable("id") final String id, @RequestBody final Student student) {
		System.out.println("::update the Student record::");
		return registrationService.update(id, student);
	}

	@PostMapping
	public Mono save(@RequestBody final Student student) {
		System.out.println("will insert the student's record :: "+ student.getId() + " :: " + student.getFirstName());
		return registrationService.save(student);
	}

	@DeleteMapping("{id}")
	public Mono delete(@PathVariable final String id) {
		System.out.println("::will delete a Student record::");
		return registrationService.delete(id);
	}
}

RegistrationRepository.java

package com.reactiveCRUD.universityApp.repository;

import org.springframework.data.mongodb.repository.ReactiveMongoRepository;
import org.springframework.stereotype.Repository;

import com.reactiveCRUD.universityApp.model.Student;

@Repository
public interface RegistrationRepository extends  ReactiveMongoRepository<Student, String>{

}

RegistrationService.java

package com.reactiveCRUD.universityApp.service;

import java.util.Objects;

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

import com.reactiveCRUD.universityApp.model.Student;
import com.reactiveCRUD.universityApp.repository.RegistrationRepository;

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

@Service
@Transactional
@AllArgsConstructor
public class RegistrationService {

	@Autowired
	private RegistrationRepository registrationRepository;

	public Flux<Student> getAll() {
		return registrationRepository.findAll().switchIfEmpty(Flux.empty());
	}

	public Mono<Student> getById(final String id) {
		return registrationRepository.findById(id);
	}

	public Mono update(final String id, final Student student) {
		return registrationRepository.save(student);
	}

	public Mono save(final Student student) {
		return registrationRepository.save(student);
	}
	
	public Mono delete(final String id) {
		final Mono<Student> dbStudent = getById(id);
		if (Objects.isNull(dbStudent)) {
			return Mono.empty();
		}
		return getById(id).switchIfEmpty(Mono.empty()).filter(Objects::nonNull).flatMap(studentToBeDeleted -> registrationRepository
				.delete(studentToBeDeleted).then(Mono.just(studentToBeDeleted)));
	}
}

Student.java

package com.reactiveCRUD.universityApp.model;

import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.mapping.Document;

import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.ToString;

@Data
@Builder
@AllArgsConstructor
@Document
@ToString
public class Student {
	
	@Id
	private String id;
	private String firstName;
	private String lastName;
	
	public String getId() {
		return id;
	}
	public void setId(String id) {
		this.id = id;
	}
	public String getFirstName() {
		return firstName;
	}
	public void setFirstName(String firstName) {
		this.firstName = firstName;
	}
	public String getLastName() {
		return lastName;
	}
	public void setLastName(String lastName) {
		this.lastName = lastName;
	}

}

UniversityAppApplication.java

package com.reactiveCRUD.universityApp;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class UniversityAppApplication {

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

}

Hi @Akashpatel579 thank you for this precise summary of your code! I just have one question:

Coud you help me understand public Mono update(final String id, final Student student) of the RegistrationService? As far as I understand the contents of the method, the String id is never used and the new student is just "appended" to all existing ones, or am I missing something? Because the ReactiveMongoRepository does not have an id to search/filter for.

Hi @Akashpatel579 thank you for this precise summary of your code! I just have one question:

Coud you help me understand public Mono update(final String id, final Student student) of the RegistrationService? As far as I understand the contents of the method, the String id is never used and the new student is just "appended" to all existing ones, or am I missing something? Because the ReactiveMongoRepository does not have an id to search/filter for.

Yes you are right, the same logic has been used for insert and update.