java 使用GraphQL-关联对象

GraphQL并不会实现关联查询，数据关联需要程序自己实现

官网首页有介绍获取多个资源只需要一个请求，如想获取用户信息和身份证信息，原来需要先查用户信息，再通过用户id查询身份证信息，而在GraphQL中一次请求就可以实现。

对于这个观点我不敢苟同，可能我还没有体会到这种感觉，我认为只要需求明确，多个资源一次请求在RESTFUl中同样可以实现。

废话不说了，进入在正题

　　之前已经实现了对user对象的查询操作，现在对user添加一个card属性，操作user对象时可以关联到card信息

User.java

public class User {

    private int age;

    private long id;

    private String name;

    private Card card;

    public User(int age, long id, String name, Card card) {

        this.age = age;

        this.id = id;

        this.name = name;

        this.card = card;

    }

    public Card getCard() {

        return card;

    }

    public void setCard(Card card) {

        this.card = card;

    }

    public User(int age, long id, String name) {

        this.age = age;

        this.id = id;

        this.name = name;

    }

    public int getAge() {

        return age;

    }

    public void setAge(int age) {

        this.age = age;

    }

    public long getId() {

        return id;

    }

    public void setId(long id) {

        this.id = id;

    }

    public String getName() {

        return name;

    }

    public void setName(String name) {

        this.name = name;

    }

}

Card.java

public class Card {

    private String cardNumber;

    private Long userId;

    public Card(String cardNumber, Long userId) {

        this.cardNumber = cardNumber;

        this.userId = userId;

    }

    public String getCardNumber() {

        return cardNumber;

    }

    public void setCardNumber(String cardNumber) {

        this.cardNumber = cardNumber;

    }

    public Long getUserId() {

        return userId;

    }

    public void setUserId(Long userId) {

        this.userId = userId;

    }

}

user.graphqls

#对应的User定义如下

schema {    #定义查询

    query: UserQuery

}

type UserQuery {    #定义查询类型

    user(id:Long) : User    #指定对象以及参数类型

}

type User { #定义对象

    id: Long!   #!表示非空

    name:String

    age:Int

    card:Card

}

type Card {

    cardNumber:String

    userId:Long

}

demo

import clc.bean.Card;

import clc.bean.User;

import graphql.ExecutionResult;

import graphql.GraphQL;

import graphql.schema.GraphQLSchema;

import graphql.schema.idl.RuntimeWiring;

import graphql.schema.idl.SchemaGenerator;

import graphql.schema.idl.SchemaParser;

import graphql.schema.idl.TypeDefinitionRegistry;

import org.apache.commons.io.IOUtils;

/**

 * ClassName: GraphQLSDLDemo<br/>

 * Description: <br/>

 * date: 2019/6/28 11:19 AM<br/>

 *

 * @author chengluchao

 * @since JDK 1.8

 */

public class GraphQLSDLDemo2 {

    public static void main(String[] args) throws Exception {

        //读取graphqls文件

        String fileName = "user.graphqls";

        String fileContent = IOUtils.toString(GraphQLSDLDemo2.class.getClassLoader().getResource(fileName), "UTF-8");

        //解析文件

        TypeDefinitionRegistry typeDefinitionRegistry = new SchemaParser().parse(fileContent);

        RuntimeWiring wiring = RuntimeWiring.newRuntimeWiring()

                .type("UserQuery", builder ->

                        builder.dataFetcher("user", environment -> {

                            Long id = environment.getArgument("id");

                            Card card = new Card("123456", id);

                            return new User(18, id, "user0" + id, card);

                        })

                )

                .build();

        GraphQLSchema graphQLSchema = new SchemaGenerator().makeExecutableSchema(typeDefinitionRegistry, wiring);

        GraphQL graphQL = GraphQL.newGraphQL(graphQLSchema).build();

        String query = "{user(id:15){id,name,age,card{cardNumber,userId}}}";

        ExecutionResult result = graphQL.execute(query);

        System.out.println("query: " + query);

        System.out.println(result.toSpecification());

    }

}

query: {user(id:15){id,name,age,card{cardNumber,userId}}}
{data={user={id=15, name=user015, age=18, card={cardNumber=123456, userId=15}}}}

再次强调，关联信息是程序控制的，并不是GraphQL

巴特西

java 使用GraphQL-关联对象

最新文章

热门文章