Spring Data Reactive MongoDB CRUD Example

vIns

4 years ago

Overview:

In this article, I would like to show how to perform various CRUD Operations with Spring Data Reactive MongoDB Repository.

Project Setup:

Lets first create a simple spring boot project with the required dependencies like Spring Data Reactive MongoDB.

Sample Application:

We are going to develop a simple spring boot application for freelancers in which the users can register themselves. So that people who want to hire freelancers can search with specific skill sets.

MongoDB Setup:

I use docker-compose to set up MongoDB.

version: "3"
services:
  mongo:
    image: mongo
    ports:
      - 27017:27017    
    environment:
      MONGO_INITDB_ROOT_USERNAME: admin
      MONGO_INITDB_ROOT_PASSWORD: password
  mongo-express:
    image: mongo-express
    ports:
      - 8081:8081
    restart: always
    depends_on:
    - mongo
    environment:
      ME_CONFIG_MONGODB_ADMINUSERNAME: admin
      ME_CONFIG_MONGODB_ADMINPASSWORD: password
      ME_CONFIG_MONGODB_SERVER: mongo

Entity:

The entity class is designed as below. I use lombok for the getters and setters.

@Data
@Document
@ToString
public class Freelancer {

    @Id
    private String id;
    private String name;
    private int age;
    private List<String> skills;

}

Spring Data Reactive MongoDB Repository:

We create a repository to do basic CRUD Operations by extending ReactiveMongoRepository. We also add couple of methods to the interface for searching with specific skill sets.

findBySkillsAll – We might want to search for people with all given skills.
findBySkillsIn – We might want to search for people containing 1 of the given skills.

@Repository
public interface FreelancerRepository extends ReactiveMongoRepository<Freelancer, String> {

    @Query("{ 'skills': { $all: ?0 } }")
    Flux<Freelancer> findBySkillsAll(List<String> skills);

    Flux<Freelancer> findBySkillsIn(List<String> skills);

}

Service:

Let’s create a service class for the CRUD operations and for the above search functionality.

@Service
public class FreelancerService {

    @Autowired
    private FreelancerRepository repository;

    public Flux<Freelancer> findBySkillsOne(final List<String> skills){
        return this.repository.findBySkillsIn(skills);
    }

    public Flux<Freelancer> findBySkillsAll(final List<String> skills){
        return this.repository.findBySkillsAll(skills);
    }

    public Mono<Freelancer> getPerson(final String id){
        return this.repository.findById(id);
    }

    public Mono<Freelancer> savePerson(final Freelancer person){
        return this.repository.save(person);
    }

    public Mono<Freelancer> updatePerson(final Freelancer person){
        return this.repository.findById(person.getId())
                    .map(p -> person)
                    .flatMap(this.repository::save);
    }

    public Mono<Void> deletePerson(final String id){
        return this.repository.deleteById(id);
    }

}

REST Controller:

Lest create the controller as shown here. Do note that when we use reactive driver nothing happens until we subscribe to that action. If you notice, even a delete method which could have been ‘void’ return type returns a Mono<Void>. If you want the return type to be void, ensure that you are subscribing to that Flux / Mono from the Spring Data Reactive MongoDB repository. Otherwise it will not work. I directly expose entity class for this demo. In real life you might want to use a DTO.

@RestController
public class FreelancerController {

    @Autowired
    private FreelancerService freelancerService;

    @GetMapping("/person/skills-one/{skills}")
    public Flux<Freelancer> findBySkills(@PathVariable List<String> skills){
        return this.freelancerService.findBySkillsOne(skills);
    }

    @GetMapping("/person/skills-all/{skills}")
    public Flux<Freelancer> findByAllSkills(@PathVariable List<String> skills){
        return this.freelancerService.findBySkillsAll(skills);
    }

    @GetMapping("/person/{id}")
    public Mono<Freelancer> getPerson(@PathVariable String id){
        return this.freelancerService.getPerson(id);
    }

    @PostMapping("/person")
    public Mono<Freelancer> createPerson(@RequestBody Freelancer person){
        return this.freelancerService.savePerson(person);
    }

    @PutMapping("/person")
    public Mono<Freelancer> updatePerson(@RequestBody Freelancer person){
        return this.freelancerService.updatePerson(person);
    }
    
    @DeleteMapping("/person/{id}")
    public Mono<Void> deletePerson(@PathVariable String id){
        return this.freelancerService.deletePerson(id);
    }

}

Application Properties:

spring.data.mongodb.database=admin
spring.data.mongodb.username=admin
spring.data.mongodb.password=password

CRUD Operations:

Lets start the application to perform the various CRUD operations.
I register few freelancers as shown here using the POST endpoint.

{
    "name": "sam",
    "age": 40,
    "skills": [ "js", "react", "python"]
}

{
    "name": "jack",
    "age": 38,
    "skills": [ "js", "angular", "postgres"]
}

{
    "name": "james",
    "age": 30,
    "skills": [ "java", "reactor", "mongo"]
}

{
    "name": "smith",
    "age": 32,
    "skills": [ "qa", "selenium"]
}