GraphQL in Java EE Application

In a Maven-based development, start by adding the GraphQl dependency to your pom.xml file

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

Create a directory in your resources and create a file with the name schema.graphqls

This file is gonna contain a schema that defines each field of your object and it's type.

To define the schema we'll use a special graphql dsl referred to as SDL.

SDL example:

type Query {
    gundamWings: [Gundam]
}
type Gundam {
  name: String
  type: String
  pilot: Pilot
}
type Pilot {
  id: String
  name: String
  Affiliation: String
}
type Mutation{
    addGundam(gundam:Gundam):Gundam
}

The last step is to add a Controller

@Controller
public class GundamWingsGraphQlController {
    @Autowired
    private GundamWingsRepository gundamWingsRepository;
    @QueryMapping
    public List<Gundam> gundamWingsList(){
        return gundamWingsRepository.findAll();
    }
    @MutationMapping
    public Gundam addGundam(@Argument Gundam gundam){
        return gundamWingsRepository.save(gundam);
    }
}

The first method is for listing the data and the second one is to add an object.