graphql学习（三）一些和GraphQL相关的

偏执的太偏执、 2022-06-13 11:27 214阅读 0赞

今天在老大的指导下，稍微看了一下graphql-java，稍微有点了解，但是还不是很了解，本篇文章不介绍。今天还进一步了解了一下Restful API，对这东西有了更深的了解，越来越感受到是一种代码风格，今天还把PUT，POST，GET和DELETE方法都测试了一下，但是距离熟练运用在项目中，还是有很大差距的。今天接触的东西比较零散，故这篇博客不讲这些东西。

--------------------

这篇博客主要是介绍之前接触的一下和GraphQL相关的东西。

# **一、GraphQL一个在线的示例网站** #

这里主要介绍一个GraphQL一个在线的示例网站[https://sandbox.learngraphql.com/][https_sandbox.learngraphql.com]，不知道这个网站是公开的还是个人的，里面自带了一些数据，可以通过右侧的Docs查看，主要涉及到以下几个表，内部也自带一下数据，主要提供的是Query和mutation两个功能，GraphQL涉及到的也就是这两个功能。

*  posts
 *  latestPost
 *  recentPosts
 *  post
 *  authors
 *  author

在左侧输入schema语句，即可在右侧输出查询到的结果，对于其他的查询也可自己试试，下面的示例主要是查询posts表下的数据，同时级联查询author和comments表下的数据，这样就使得查询很简单，同时前端传递是十分易于扩展：

{
      post:posts{
        _id
        author{
          _id
          name
          twitterHandle
        }
        comments{
          _id
          content
        }
      }
    
    }

输出以下结果

{
      "data": { "post": [ { "_id": "0176413761b289e6d64c2c14a758c1c7", "author": { "_id": "indi", "name": "Kasun Indi", "twitterHandle": "@indi" }, "comments": [ { "_id": "cid-46907332", "content": "This is a very good blog post" }, { "_id": "cid-59329432", "content": "Keep up the good work" } ] }, { "_id": "03390abb5570ce03ae524397d215713b", "author": { "_id": "pahan", "name": "Pahan Sarathchandra", "twitterHandle": "@pahans" }, "comments": [ { "_id": "cid-46907332", "content": "This is a very good blog post" }, { "_id": "cid-59329432", "content": "Keep up the good work" } ] }, { "_id": "0be4bea0330ccb5ecf781a9f69a64bc8", "author": { "_id": "arunoda", "name": "Arunoda Susiripala", "twitterHandle": "@arunoda" }, "comments": [ { "_id": "cid-46907332", "content": "This is a very good blog post" }, { "_id": "cid-59329432", "content": "Keep up the good work" } ] }, { "_id": "19085291c89f0d04943093c4ff16b664", "author": { "_id": "arunoda", "name": "Arunoda Susiripala", "twitterHandle": "@arunoda" }, "comments": [ { "_id": "cid-46907332", "content": "This is a very good blog post" }, { "_id": "cid-59329432", "content": "Keep up the good work" } ] }, { "_id": "1afff9dfb0b97b5882c72cb60844e034", "author": { "_id": "arunoda", "name": "Arunoda Susiripala", "twitterHandle": "@arunoda" }, "comments": [ { "_id": "cid-46907332", "content": "This is a very good blog post" }, { "_id": "cid-59329432", "content": "Keep up the good work" } ] }, { "_id": "1bd16dfab1de982317d2ba4382ec8c86", "author": { "_id": "arunoda", "name": "Arunoda Susiripala", "twitterHandle": "@arunoda" }, "comments": [ { "_id": "cid-46907332", "content": "This is a very good blog post" }, { "_id": "cid-59329432", "content": "Keep up the good work" } ] }, { "_id": "285292901bb38be8f57dd2885c517826", "author": { "_id": "arunoda", "name": "Arunoda Susiripala", "twitterHandle": "@arunoda" }, "comments": [ { "_id": "cid-46907332", "content": "This is a very good blog post" }, { "_id": "cid-59329432", "content": "Keep up the good work" } ] }, { "_id": "2f6b59fd0b182dc6e2f0051696c70d70", "author": { "_id": "arunoda", "name": "Arunoda Susiripala", "twitterHandle": "@arunoda" }, "comments": [ { "_id": "cid-46907332", "content": "This is a very good blog post" }, { "_id": "cid-59329432", "content": "Keep up the good work" } ] }, { "_id": "3d7a3853bf435c0f00e46e15257a94d9", "author": { "_id": "arunoda", "name": "Arunoda Susiripala", "twitterHandle": "@arunoda" }, "comments": [ { "_id": "cid-46907332", "content": "This is a very good blog post" }, { "_id": "cid-59329432", "content": "Keep up the good work" } ] } ] } }

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二、网上很火的一个java实现GraphQL服务器的Demo，但是我自己测试的时候有一点小Bug，以下是我修改过的，直接复制即可使用（起码在我的IDE上是这样的）；

User.java

public class User { 
        private int id;
        private int age;
        private int sex;
        private String name;
        private String pic;
        // getter, setter... 
    }

Test.java

import static graphql.schema.GraphQLFieldDefinition.newFieldDefinition;
    import static graphql.schema.GraphQLObjectType.newObject;
    import static graphql.schema.GraphQLArgument.newArgument;
    
    import java.util.ArrayList;
    import java.util.List;
    import java.util.Map;
    
    import graphql.GraphQL;
    import graphql.Scalars;
    import graphql.schema.GraphQLFieldDefinition;
    import graphql.schema.GraphQLList;
    import graphql.schema.GraphQLOutputType;
    import graphql.schema.GraphQLSchema;
    
    public class Test { 
        private GraphQLOutputType userType;
    
        private void initOutputType() {
            /** * 会员对象结构 */
            userType = newObject().name("User").field(newFieldDefinition().name("id").type(Scalars.GraphQLInt).build())
                    .field(newFieldDefinition().name("age").type(Scalars.GraphQLInt).build())
                    .field(newFieldDefinition().name("sex").type(Scalars.GraphQLInt).build())
                    .field(newFieldDefinition().name("name").type(Scalars.GraphQLString).build())
                    .field(newFieldDefinition().name("pic").type(Scalars.GraphQLString).build()).build();
        }
    
        /** * 查询单个用户信息 * * @return */
        private GraphQLFieldDefinition createUserField() {
            return GraphQLFieldDefinition.newFieldDefinition().name("user")
                    .argument(newArgument().name("id").type(Scalars.GraphQLInt).build()).type(userType)
                    .dataFetcher(environment -> {
                        // 获取查询参数
                        int id = environment.getArgument("id");
    
                        // 执行查询, 这里随便用一些测试数据来说明问题
                        User user = new User();
                        user.setId(id);
                        user.setAge(id + 15);
                        user.setSex(id % 2);
                        user.setName("Name_" + id);
                        user.setPic("pic_" + id + ".jpg");
                        return user;
                    }).build();
        }
    
        /** * 查询多个会员信息 * * @return */
        private GraphQLFieldDefinition createUsersField() {
            return GraphQLFieldDefinition.newFieldDefinition().name("users")
                    .argument(newArgument().name("page").type(Scalars.GraphQLInt).build())
                    .argument(newArgument().name("size").type(Scalars.GraphQLInt).build())
                    .argument(newArgument().name("name").type(Scalars.GraphQLString).build())
                    .type(new GraphQLList(userType)).dataFetcher(environment -> {
                        // 获取查询参数
                        int page = environment.getArgument("page");
                        int size = environment.getArgument("size");
                        String name = environment.getArgument("name");
    
                        // 执行查询, 这里随便用一些测试数据来说明问题
                        List<User> list = new ArrayList<>(size);
                        for (int i = 0; i < size; i++) {
                            User user = new User();
                            user.setId(i);
                            user.setAge(i + 15);
                            user.setSex(i % 2);
                            user.setName(name + "_" + page + "_" + i);
                            user.setPic("pic_" + i + ".jpg");
                            list.add(user);
                        }
                        return list;
                    }).build();
        }
    
        private GraphQLSchema schema;
    
        public Test() {
            initOutputType();
            schema = GraphQLSchema.newSchema()
                    .query(newObject().name("GraphQuery").field(createUsersField()).field(createUserField()).build())
                    .build();
        }
    
        public static void main(String[] args) {
            GraphQLSchema schema = new Test().schema;
    
            String query1 = "{users(page:2,size:5,name:\"john\") {id,sex,name,pic}}";
            String query2 = "{user(id:6) {id,sex,name,pic}}";
            String query3 = "{user(id:6) {id,sex,name,pic},users(page:2,size:5,name:\"john\") {id,sex,name,pic}}";
    
            Map<String, Object> result1 = (Map<String, Object>) new GraphQL(schema).execute(query1).getData();
            Map<String, Object> result2 = (Map<String, Object>) new GraphQL(schema).execute(query2).getData();
            Map<String, Object> result3 = (Map<String, Object>) new GraphQL(schema).execute(query3).getData();
    
            // 查询用户列表
            System.out.println(result1);
            // 查询单个用户
            System.out.println(result2);
            // 单个用户、跟用户列表一起查
            System.out.println(result3);
    
        }
    
    }

运行结果：

{
        users=[
            {
                id=0,
                sex=0,
                name=john_2_0,
                pic=pic_0.jpg
            },
            {
                id=1,
                sex=1,
                name=john_2_1,
                pic=pic_1.jpg
            },
            {
                id=2,
                sex=0,
                name=john_2_2,
                pic=pic_2.jpg
            },
            {
                id=3,
                sex=1,
                name=john_2_3,
                pic=pic_3.jpg
            },
            {
                id=4,
                sex=0,
                name=john_2_4,
                pic=pic_4.jpg
            }
        ]
    }
    -------------------------------------------
    {
        user={
            id=6,
            sex=0,
            name=Name_6,
            pic=pic_6.jpg
        }
    }
    -------------------------------------------
    {
        user={
            id=6,
            sex=0,
            name=Name_6,
            pic=pic_6.jpg
        },
        users=[
            {
                id=0,
                sex=0,
                name=john_2_0,
                pic=pic_0.jpg
            },
            {
                id=1,
                sex=1,
                name=john_2_1,
                pic=pic_1.jpg
            },
            {
                id=2,
                sex=0,
                name=john_2_2,
                pic=pic_2.jpg
            },
            {
                id=3,
                sex=1,
                name=john_2_3,
                pic=pic_3.jpg
            },
            {
                id=4,
                sex=0,
                name=john_2_4,
                pic=pic_4.jpg
            }
        ]
    }

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如果文章中有任何侵犯到您的，望告知642646522@qq.com，一定在第一时间删改。

[https_sandbox.learngraphql.com]: https://sandbox.learngraphql.com/