少说话多写代码之.net core——001：建一个api

一、.net core环境准备

直接装visualstudio 2017，具体安装方法，自行下载安装即可。

二、.net core使用

用.net core编写一个webapi。

具体过程如下，

1、新建工程

2、添加模型类

    public class MyItem
    {
        public long Id { get; set; }
        public string Name { get; set; }
        public bool IsComplete { get; set; }
    }

3、添加数据上下文

  public class MyContext: DbContext
    {
        public MyContext(DbContextOptions<MyContext> options)
            : base(options)
        {
        }
        public DbSet<MyItem> MyItems { get; set; }
    }

4、注册数据上下文

 public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            //我的新增代码
            services.AddDbContext<MyContext>(opt =>
               opt.UseInMemoryDatabase("TodoList"));
            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
                app.UseHsts();
            }

            app.UseHttpsRedirection();
            app.UseMvc();
        }
    }

5、添加控制器及相关方法

添加get，post，delete等方法

 public class MyController : Controller
    {
        private readonly MyContext _context;

        public MyController(MyContext context)
        {
            _context = context;

            if (_context.MyItems.Count() == 0)
            {
                _context.MyItems.Add(new MyItem {Id=99, Name = "我的自定义的控制器_99 "+DateTime.Now.ToLocalTime() });
                _context.MyItems.Add(new MyItem {Id =100, Name = "我的自定义的控制器_100 " + DateTime.Now.ToLocalTime() });
                _context.SaveChanges();
            }
        }

        // GET: api/Todo
        [HttpGet]
        public async Task<ActionResult<IEnumerable<MyItem>>> GetMyItems()
        {
            return await _context.MyItems.ToListAsync();
        }

        // GET: api/Todo/99
        [HttpGet("{id}")]
        public async Task<ActionResult<MyItem>> GetMyItem(long id)
        {
            var todoItem = await _context.MyItems.FindAsync(id);

            if (todoItem == null)
            {
                return NotFound();
            }

            return todoItem;
        }
        // POST: api/Todo
        [HttpPost]
        public async Task<ActionResult<MyItem>> PostMyItem(MyItem item)
        {
            _context.MyItems.Add(item);
            await _context.SaveChangesAsync();

            return CreatedAtAction("GetMyItem", new { id = item.Id , Name = item.Name}, item);
        }

        [HttpPut("{id}")]
        public async Task<IActionResult> PutMyItem(long id, MyItem item)
        {
            if (id != item.Id)
            {
                return BadRequest();
            }
            _context.Entry(item).State = EntityState.Modified;
            await _context.SaveChangesAsync();

            return NoContent();
        }

        // DELETE: api/Todo/101
        [HttpDelete("{id}")]
        public async Task<ActionResult<MyItem>> DeleteMyItem(long id)
        {
            var todoItem = await _context.MyItems.FindAsync(id);
            if (todoItem == null)
            {
                return NotFound();
            }

            _context.MyItems.Remove(todoItem);
            await _context.SaveChangesAsync();

            return todoItem;
        }
    }

6、设置路由

在刚新加的控制器上新增路由，比如

    [Route("api/My")]
    [ApiController]
    public class MyController : Controller

同时在launchSettings.json中设置，访问默认路径，比如

{
  "$schema": "http://json.schemastore.org/launchsettings.json",
  "iisSettings": {
    "windowsAuthentication": false, 
    "anonymousAuthentication": true, 
    "iisExpress": {
      "applicationUrl": "http://localhost:50228",
      "sslPort": 44364
    }
  },
  "profiles": {
    "IIS Express": {
      "commandName": "IISExpress",
      "launchBrowser": true,
      "launchUrl": "api/My",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      }
    },
    "MyToDoApi": {
      "commandName": "Project",
      "launchBrowser": true,
      "launchUrl": "api/My",
      "applicationUrl": "https://localhost:5001;http://localhost:5000",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      }
    }
  }
}

7、测试

在工程上启用调试，本文使用postman进行测试。

启用调试后，在浏览器页面中地址为：https://localhost:44364/api/My，显示内容如下，

[{"id":99,"name":"我的自定义的控制器_99 2019/1/13 23:26:24","isComplete":false},{"id":100,"name":"我的自定义的控制器_100 2019/1/13 23:26:24","isComplete":false}]

7.1、测试get方法

GetMyItems调用如下，

GetMyItem调用如下，

7.2、测试post方法

PostMyItem调用如下，

调用后，在浏览器页面验证如下

7.3、测试put方法

PutMyItem调用如下

浏览器中验证，

7.4、测试delete方法

DeleteMyItem调用如下，

浏览器中验证，

工程文件下载： https://download.csdn.net/upload/10914869