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Java GraphQL Beispiele für Anfänger [mit Spring Boot]

In diesem Artikel werden wir ein Java GraphQL-Beispiel durchgehen und einen einfachen GraphQL-Server mit Spring Boot erstellen.





Solche Girls lieben auch Java GraphQL-Beispiele mit Spring Boot!



GraphQL ist eine Abfragesprache für APIs , mit der Clients die begrenzte Datenmenge abfragen können, die sie benötigen. Dadurch können Clients Daten in einer begrenzten Anzahl von Abfragen erfassen. GraphQL ist ein stark typisiertes Protokoll und alle Datenoperationen werden anhand des GraphQL-Schemas validiert.



In diesem Artikel werden wir ein Java GraphQL-Beispiel durchgehen und einen einfachen GraphQL-Server mit Spring Boot erstellen.



Hinzufügen von Maven-Abhängigkeiten



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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