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  • GraphQL教程(一)。.net Core API2.1

    1.创建项目
    2.对类库操作,在这里建立三个文件夹,其中一个文件夹改名为schema
    3.建立IMovieService,IActorService接口与实现类

    GraphQL是什么将放到第二章来讲,第一章为GraphQL的准备工程

    1.创建项目

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    之后选择空项目,.net core 2.1
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    添加类库,取名
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    2.对类库操作,在这里建立三个文件夹,其中一个文件夹改名为schema

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    Movie:用于确定movie类与actor类得类型
    Schema:
    Service:用来写服务的

    安装GraphQL包,加入类库中
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    在Movies文件夹中建立Movie类,Actor类与枚举MovieRating,MovieRating为Movie中其中一个的枚举
    Movie

    using GraphStudy.Movies.Movies;
    using System;
    
    namespace GraphStudy.Movie.Movies
    {
        //电影类
        public class Movie
        {
            public int Id { get; set; }//电影编号
            public string Name { get; set; }
            public DateTime ReleaseDate { get; set; }//上映时间
            public string Company { get; set; }
            public int ActorId { get; set; }//演员ID
            public MovieRating MovieRating { get; set; }//电影等级枚举
        }
    }
    

    枚举MovieRating

    using System;
    
    namespace GraphStudy.Movies.Movies
    {
        [Flags]
        public enum MovieRating
        {
            //这是电影的5个等级
            Unrated = 0,
            G = 1,
            PG = 2,
            PG13 = 3,
            R = 4,
            NC17 = 5
        }
    }
    
    

    Actor演员类,写简单点

    namespace GraphStudy.Movies.Movies
    {
        //演员类
        public class Actor
        {
            public int Id { get; set; }
            public string Name { get; set; }
        }
    }
    

    **

    3.建立IMovieService,IActorService接口与实现类

    **
    在Services文件夹添加IMovieService,IActorService接口与MovieService,ActorServices实现类

    IMovieService接口

    using GraphStudy.Movies.Movies;
    using System.Collections.Generic;
    using System.Threading.Tasks;
    
    namespace GraphStudy.Movies.Services
    {
        public interface IMovieService
        {
            Task<IEnumerable<Movie>> GetAsyncs();//获取所有列
            Task<Movie> GetByIdAsync(int id);//获取某个对应id属性的列
            Task<Movie> CreateAsync(Movie movie);//创建
        }
    }
    

    IActorService接口

    using GraphStudy.Movies.Movies;
    using System.Collections.Generic;
    using System.Threading.Tasks;
    
    namespace GraphStudy.Movies.Services
    {
        public interface IActorService
        {
            Task<Actor> GetByIdAsync(int id);//获取某个演员信息
            Task<IEnumerable<Actor>> GetAsync();//获取所有演员信息
        }
    }
    

    IMovieService接口的实现类MovieService类

    using GraphStudy.Movies.Movies;
    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Threading.Tasks;
    
    namespace GraphStudy.Movies.Services
    {
        public class MovieService : IMovieService
        {
            //因为我们需要创建子列表,所以一要用到IList
            private readonly IList<Movie> _movie;
    
            public MovieService()
            {
                _movie=new List<Movie>
                {
                    #region 电影列表
        
                    new Movie
                    {
                        Id = 1,
                        Name = "肖申克的救赎The Shawshank Redemption",
                        Company = "美国",
                        MovieRating = MovieRating.G,
                        ActorId = 1,
                        ReleaseDate = new DateTime(1994-10-14)
                    },
                    new Movie
                    {
                        Id = 2,
                        Name = "这个杀手不太冷 Léon ",
                        Company = "法国",
                        MovieRating = MovieRating.NC17,
                        ActorId = 2,
                        ReleaseDate = new DateTime(1994-09-14)
                    },
                    new Movie
                    {
                        Id = 3,
                        Name = "三傻大闹好莱坞",
                        Company = "印度",
                        MovieRating = MovieRating.PG,
                        ActorId = 3,
                        ReleaseDate = new DateTime(2011-12-08)
                    },
                    new Movie
                    {
                        Id = 4,
                        Name = "功夫",
                        Company = "美国",
                        MovieRating = MovieRating.G,
                        ActorId = 4,
                        ReleaseDate = new DateTime(2004-12-23)
                    }
                    #endregion
                };
            }
    
    
            public Task<Movie> CreateAsync(Movie movie)
            {
                _movie.Add(movie);
                return Task.FromResult(movie);
            }
    
            public Task<IEnumerable<Movie>> GetAsyncs()
            {
                return Task.FromResult(_movie.AsEnumerable());
            }
    
            public Task<Movie> GetByIdAsync(int id)
            {
                //在这里需要做个判断这个id是否存在
                var movie = _movie.SingleOrDefault(x => x.Id == id);
                if (movie == null)
                {
                    throw new ArgumentException(String.Format("Movie ID {0} 不正确", id););
                }
    
                return Task.FromResult(movie);
            }
        }
    }
    
    

    IActorService接口的实现,ActorService类

    using GraphStudy.Movies.Movies;
    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Threading.Tasks;
    
    namespace GraphStudy.Movies.Services
    {
        public class ActorService : IActorService
        {
            private readonly IList<Actor> _actor;
    
            public ActorService()
            {
                _actor=new List<Actor>
                {
                    #region 演员列表
    
                    new Actor
                    {
                        Id = 1,
                        Name = "肖申克"
                    },
                    new Actor
                    {
                        Id=2,
                        Name = "让·雷诺"
                    },
                    new Actor
                    {
                        Id = 3,
                        Name = "阿米尔·汗,卡琳娜·卡普尔 ",
                    },
                    new Actor
                    {
                        Id=4,
                        Name = "周星驰,元秋 元华"
                    }
                    #endregion
                };
            }
    
            public Task<IEnumerable<Actor>> GetAsync()
            {
                return Task.FromResult(_actor.AsEnumerable());
            }
    
            public Task<Actor> GetByIdAsync(int id)
            {
                var actor = _actor.SingleOrDefault(x => x.Id == id);
                if (actor == null)
                {
                    throw new ArgumentException(String.Format("Actor ID {0} 不存在",id));
                }
    
                return Task.FromResult(actor);
            }
        }
    }
    
    

    此处注意:Movie与Actor中的ID为一对一,所以ActorService里面new Actor中的id只可唯一,不可以重复,会出错

    4.在startup注册服务

    添加引用
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    如果出现以下情况
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    将类库的版本降为.net core 2.1
    右键点击类库->属性
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    如果无效,请把引用类库取消在引用一次类库
    然后进行服务注册
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    这是第一部分

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  • 原文地址:https://www.cnblogs.com/zuiren/p/10849935.html
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