一、准备工作

1.Visual Studio NuGet程序包源配置

源地址：
http://47.102.150.59:8087/nuget/

一些辅助功能包，能提高开发效率

api教程完整版pdf（Api开发教程）

2.创建项目

选择项目类型、自定义项目名称

api教程完整版pdf（Api开发教程）

3.基础配置

项目应用端口配置、IOC容器配置、日志配置、数据库配置、Map映射配置…

 //Program.cs         public static void Main(string[] args)         {             var config = new ConfigurationBuilder()                 .SetBasePath(Directory.GetCurrentDirectory())                 // 添加端口配置文件                 .AddJsonFile("hosting.json", true)                 .Build();              var host = Host.CreateDefaultBuilder(args)                 // 添加Autofac作为IOC容器                 .UseServiceProviderFactory(AppServiceProvider.Instance().AutofacServiceProviderFactory)                 .ConfigureWebHostDefaults(webHostBuilder =>                 {                     webHostBuilder                       .UseContentRoot(Directory.GetCurrentDirectory())                       .UseConfiguration(config)                       .UseStartup<Startup>();                 })                 .Build();              host.Run();         }

 //Startup.cs         public void ConfigureServices(IServiceCollection services)         {             MapperHelper.CreateMap();//Map映射配置             services.UseNCoreAspNet<NCoreAspNetOptions>(options =>             {                 //日志配置                 options.Log4netConfig = "log4net.config";                 options.UseUpload = true;                 options.UseAnyCors = true;                 options.ApiSecurityFilter = false;                 //数据库配置                 options.DefaultDBOptions = new DefaultDBOptions                 {                     DBSectionName = "DBConnectionSetting",                     DefaultConnectionName = "defaultConnection"                 };             });         }

二、API实现

1.创建数据模型（ViewModel）

定义接口需要数据属性（名称、类型、约束等…）【属性命名规则全部用小写，方便前端 JS 调用时不用检查某个属性大小写问题】

     /// <summary>     ///用户基本信息     /// </summary>     public class UserViewMmodel     {         /// <summary>         /// 用户名         /// </summary>         public string user_name { get; set; } = "hanbing";          /// <summary>         /// 昵称         /// </summary>         public string nickname { get; set; } = "老卢聊技术";          /// <summary>         /// qq号码         /// </summary>         public string qq { get; set; } = "81868164";          /// <summary>         ///微信号码         /// </summary>         public string wxid { get; set; } = "hanbing_81868164";          /// <summary>         /// 地址         /// </summary>         public string address { get; set; }          /// <summary>         /// 年龄         /// </summary>         public int age { get; set; }          /// <summary>         /// 创建时间         /// </summary>         public DateTime creation_time { get; set; }          /// <summary>         /// 版本信息         /// </summary>         public string version { get; set; }     }

2.创建控制器（Controller），编写逻辑代码

1）.设置接口输出数据格式（JSON或XML）

     [Produces("application/json")]//Controller中方法默认输出json格式数据     //[Produces("application/xml")]//Controller中方法默认输出xml格式数据     public class TestApiController : Controller

2）.设置接口路由（定义接口版本【方便后期和新版本区分】）

     [Route("api/v1/testapi")]//固定路由配置     //[Route("api/v1/[controller]")]//固定部分路由配置     public class TestApiController  : Controller

3）.设置接口请求Method，常见如下：

GET ：从服务器取出资源（一项或多项）

POST ：在服务器新建一个资源

PUT ：在服务器更新资源（客户端提供改变后的完整资源）

PATCH ：在服务器更新资源（客户端提供改变的属性）

DELETE ：从服务器删除资源

         /// <summary>         /// 返回用户信息接口         /// </summary>         /// <returns></returns>         [HttpGet]//请求方法为GET         [Route("getuser")]//自定义路由         //[Produces("application/xml")]//输出xml格式         public Task<UserViewMmodel> Index()         {}

4）.返回JSON数据格式接口

         /// <summary>         /// 返回用户信息接口         /// </summary>         /// <returns></returns>         [HttpGet]//请求方法为GET         [Route("getuser")]//自定义路由         //[Produces("application/xml")]//输出xml格式         public Task<UserViewMmodel> Index()         {             return Task.Run(() =>             {                 UserViewMmodel res = null;                 //业务逻辑代码....                 res = new UserViewMmodel                 {                     address = "上海市浦东区世纪大道200号",                     age = 23,                     creation_time = DateTime.Now,                     version = "v1.0"                 };                  return res;             });         }

5）.返回文件（输出文件）接口

         /// <summary>         /// 输出文件接口         /// </summary>         /// <returns></returns>         [HttpGet]//请求方法为GET         [Route("getfile")]//自定义路由         public FileResult Download()         {             var fileData = $"{Directory.GetCurrentDirectory()}/wwwroot/css/site.css";             var actionresult = new FileStreamResult(fileData.GetFileData().ToStream(), "text/css");             actionresult.FileDownloadName = "site.css";             return actionresult;         }

6）.裁剪图片接口

         /// <summary>         /// 裁剪图片接口         /// </summary>         /// <param name="width"></param>         /// <param name="name"></param>         /// <returns></returns>         [HttpGet]//请求方法为GET         [Route("getimage/{width}/{name}")]//自定义路由         public IActionResult GetImage(int width, string name)         {             var imgPath = $@"{Directory.GetCurrentDirectory()}/wwwroot/imgs/{name}";              //缩小图片             using (var imgBmp = new Bitmap(imgPath))             {                 //找到新尺寸                 var oWidth = imgBmp.Width;                 var oHeight = imgBmp.Height;                 var height = oHeight;                 if (width > oWidth)                 {                     width = oWidth;                 }                 else                 {                     height = width * oHeight / oWidth;                 }                 var newImg = new Bitmap(imgBmp, width, height);                 newImg.SetResolution(72, 72);                 byte[] bytes;                 using (var ms = new MemoryStream())                 {                     newImg.Save(ms, ImageFormat.Bmp);                     bytes = ms.GetBuffer();                 }                 return new FileContentResult(bytes, "image/jpeg");             }         }

7）.上传单个文件接口

         /// <summary>         /// 上传文件,需要指定name值为fromFile，如：form-data; name="fromFile"; filename="8.png"         /// </summary>         /// <param name="fromFile"></param>         /// <returns></returns>         [Route("upfile")]//自定义路由         [HttpPost]//请求方法为POST         [AllowAnonymous]         public UpFileViewModel UplodeFile([FromForm] IFormFile fromFile)         {             if (fromFile != null)             {                 using (var sm = fromFile.OpenReadStream())                 {                     string savePath = $"{Directory.GetCurrentDirectory()}/wwwroot/temp/{Id.LongId()}{fromFile.FileName.GetExtension()}";                     sm.Save(savePath);                 }                 return new UpFileViewModel { code = 0, msg = "保存成功" };             }             return new UpFileViewModel { code = 1, msg = "保存失败" };         }

8）.上传多个文件接口

         /// <summary>         /// 上传多个文件,需要指定name值为files，如：form-data; name="files"; filename="8.png"         /// </summary>         /// <param name="fromFile"></param>         /// <returns></returns>         [Route("upfiles")]//自定义路由         [HttpPost]//请求方法为POST         [AllowAnonymous]         public UpFileViewModel UplodeFiles([FromForm] IFormFileCollection files)         {             if (files != null)             {                 files.ForEach(fromFile =>                 {                     using (var sm = fromFile.OpenReadStream())                     {                         string savePath = $"{Directory.GetCurrentDirectory()}/wwwroot/temp/{Id.LongId()}{fromFile.FileName.GetExtension()}";                         sm.Save(savePath);                     }                 });                 return new UpFileViewModel { code = 0, msg = "保存成功" };             }             return new UpFileViewModel { code = 1, msg = "保存失败" };         }

9）.上传多文件接口，上传时不需要指定name参数

         /// <summary>         /// 上传时不需要指定name参数:form-data; name=""; filename="222222222222.jpg"         /// </summary>         /// <returns></returns>         [Route("upfiles2")]//自定义路由         [HttpPost]//请求方法为POST         [AllowAnonymous]         public UpFileViewModel UplodeFiles2()         {             var files = this.Request.Form?.Files;             if (files != null)             {                 files.ForEach(fromFile =>                 {                     using (var sm = fromFile.OpenReadStream())                     {                         string savePath = $"{Directory.GetCurrentDirectory()}/wwwroot/temp/{Id.LongId()}{fromFile.FileName.GetExtension()}";                         sm.Save(savePath);                     }                 });                 return new UpFileViewModel { code = 0, msg = "保存成功" };             }             return new UpFileViewModel { code = 1, msg = "保存失败" };         }

4）.待续…