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Exemples Java GraphQL pour les débutants [avec Spring Boot]

Dans cet article, nous allons parcourir un exemple Java GraphQL et créer un serveur GraphQL simple avec Spring Boot.





Les poussins comme ça aiment aussi les exemples Java GraphQL avec Spring Boot!



GraphQL est un langage de requête pour les API qui permet aux clients d'interroger la quantité limitée de données dont ils ont besoin, permettant aux clients de collecter des données dans un nombre limité de requêtes. GraphQL est un protocole fortement typé et toutes les opérations de données sont validées par rapport au schéma GraphQL.



Dans cet article, nous allons parcourir un exemple Java GraphQL et créer un serveur GraphQL simple avec Spring Boot.



Ajouter des dépendances Maven



Spring Boot .



  1. graphql-spring-boot-starter GraphQL /graphql. GraphQLSchema .
  2. graphql-java GraphQL, .
  3. graphiql-spring-boot-starter , GraphQL . 



        <dependency>
        <groupId>com.graphql-java</groupId>
        <artifactId>graphql-spring-boot-starter</artifactId>
        <version>5.0.2</version>
    </dependency>
    <dependency>
        <groupId>com.graphql-java</groupId>
        <artifactId>graphql-java-tools</artifactId>
        <version>5.2.4</version>
    </dependency>
    <dependency>
        <groupId>com.graphql-java</groupId>
        <artifactId>graphiql-spring-boot-starter</artifactId>
        <version>5.0.2</version>
    </dependency>


    POM. 



    <?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>
<groupId>com.techshard.graphql</groupId>
<artifactId>springboot-graphql</artifactId>
<version>1.0-SNAPSHOT</version>
<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.6.RELEASE</version>
    <relativePath />
</parent>
<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
</properties>
<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <dependency>
        <groupId>com.graphql-java</groupId>
        <artifactId>graphql-spring-boot-starter</artifactId>
        <version>5.0.2</version>
    </dependency>
    <dependency>
        <groupId>com.graphql-java</groupId>
        <artifactId>graphql-java-tools</artifactId>
        <version>5.2.4</version>
    </dependency>
    <dependency>
        <groupId>com.graphql-java</groupId>
        <artifactId>graphiql-spring-boot-starter</artifactId>
        <version>5.0.2</version>
    </dependency>
    <dependency>
        <groupId>com.h2database</groupId>
        <artifactId>h2</artifactId>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>1.18.8</version>
        <optional>true</optional>
    </dependency>
</dependencies>
<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
</build>
</project>


    JPA



    Vehicle JPA . Lombok, , , .





    package com.techshard.graphql.dao.entity;
import lombok.Data;
import lombok.EqualsAndHashCode;
import javax.persistence.*;
import java.io.Serializable;
import java.time.LocalDate;
@Data
@EqualsAndHashCode
@Entity
public class Vehicle implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @Column(name = "ID", nullable = false)
    @GeneratedValue(strategy = GenerationType.AUTO)
    private int id;
    @Column(name = "type", nullable = false)
    private String type;
    @Column(name = "model_code", nullable = false)
    private String modelCode;
    @Column(name = "brand_name")
    private String brandName;
    @Column(name = "launch_date")
    private LocalDate launchDate;
    private transient  String formattedDate;
    // Getter and setter
    public String getFormattedDate() {
        return getLaunchDate().toString();
    }
}


    JPA.



    package com.techshard.graphql.dao.repository;
import com.techshard.graphql.dao.entity.Vehicle;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
@Repository
public interface VehicleRepository extends JpaRepository<Vehicle, Integer> {
}


    GraphQL



    GraphQL GraphQL, Schema Definition Language (SDL — ). API, .



    GraphQL :



    type Vehicle {
id: ID!,
type: String,
modelCode: String,
brandName: String,
launchDate: String
}
type Query {
vehicles(count: Int):[Vehicle]
vehicle(id: ID):Vehicle
}
type Mutation {
createVehicle(type: String!, modelCode: String!, brandName: String, launchDate: String):Vehicle
}


    graphql src/main/resources vehicleql.graphqls. vehicleql.graphqls. , . , .graphqls.



    . GraphQL , , .



    Vehicle, . Query , GraphQL . , , . . GraphQL, .



    .



    Mutation , .



    Root Query



    Query Mutation GraphQL. . (resolver) GraphQLQueryResolver GraphQLMutationResolver. , .



    Vehicle.



    package com.techshard.graphql.query;
import com.coxautodev.graphql.tools.GraphQLQueryResolver;
import com.techshard.graphql.dao.entity.Vehicle;
import com.techshard.graphql.service.VehicleService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import java.util.List;
import java.util.Optional;
@Component
public class VehicleQuery implements GraphQLQueryResolver {
    @Autowired
    private VehicleService vehicleService;
    public List<Vehicle> getVehicles(final int count) {
        return this.vehicleService.getAllVehicles(count);
    }
    public Optional<Vehicle> getVehicle(final int id) {
        return this.vehicleService.getVehicle(id);
    }
}


    Vehicle Vehicle. , .



    .



    package com.techshard.graphql.mutation;
import com.coxautodev.graphql.tools.GraphQLMutationResolver;
import com.techshard.graphql.dao.entity.Vehicle;
import com.techshard.graphql.service.VehicleService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import java.time.LocalDate;
@Component
public class VehicleMutation implements GraphQLMutationResolver {
    @Autowired
    private VehicleService vehicleService;
    public Vehicle createVehicle(final String type, final String modelCode, final String brandName, final String launchDate) {
        return this.vehicleService.createVehicle(type, modelCode, brandName, launchDate);
    }
}


    Vehicle, Mutation .



    , .



    package com.techshard.graphql.service;
import com.techshard.graphql.dao.entity.Vehicle;
import com.techshard.graphql.dao.repository.VehicleRepository;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import java.time.LocalDate;
import java.util.List;
import java.util.Optional;
import java.util.stream.Collectors;
@Service
public class VehicleService {
    private final VehicleRepository vehicleRepository ;
    public VehicleService(final VehicleRepository vehicleRepository) {
        this.vehicleRepository = vehicleRepository ;
    }
    @Transactional
    public Vehicle createVehicle(final String type,final String modelCode, final String brandName, final String launchDate) {
        final Vehicle vehicle = new Vehicle();
        vehicle.setType(type);
        vehicle.setModelCode(modelCode);
        vehicle.setBrandName(brandName);
        vehicle.setLaunchDate(LocalDate.parse(launchDate));
        return this.vehicleRepository.save(vehicle);
    }
    @Transactional(readOnly = true)
    public List<Vehicle> getAllVehicles(final int count) {
        return this.vehicleRepository.findAll().stream().limit(count).collect(Collectors.toList());
    }
    @Transactional(readOnly = true)
    public Optional<Vehicle> getVehicle(final int id) {
        return this.vehicleRepository.findById(id);
    }
}




    . Spring Boot : http://localhost:8080/graphiql. , .





    .





    .



    mutation {
  createVehicle(type: "car", modelCode: "XYZ0192", brandName: "XYZ", launchDate: "2016-08-16") 
  {
    id
  }
}


    Vehicle. :



    {
  "data": {
    "createVehicle": {
      "id": "1"
    }
  }
}


    , .



    query {
  vehicles(count: 1) 
  {
    id, 
    type, 
    modelCode
}
}


    :



    {
  "data": {
    "vehicles": [
      {
        "id": "1",
        "type": "bus",
        "modelCode": "XYZ123"
      }
    ]
  }
}


    , , , .





    GraphQL Java Spring Boot. .



    GitHub.





    Introduction to GraphQL



    GraphQL: Core Features, Architecture, Pros, and Cons



    GraphQL, , GraphQL.



    . .

    « GraphQL »


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