[Route("api/[controller]")]
 [ApiController]
 public class UserApiController : ControllerBase
 {
 /// <summary>
 /// 获取用户信息，根据用户id
 /// </summary>
 /// <param name="id">用户id</param>
 /// <returns></returns>
 [HttpGet("getuser/{id}")]
 public ActionResult GetUser(int id)
 {
  User u = new User { Id=1,Name="Jack"};
  return Ok(new { ok = true, data = u });
 }
 /// <summary>
 /// 添加用户
 /// </summary>
 /// <param name="user">用户信息</param>
 /// <returns></returns>
 [HttpPost("postuser")]
 public ActionResult AddUser([FromBody]User user)
 {
  return Ok(new { ok = true, data = user });
 }
 }

 public class User
 { 
 /// <summary>
 /// 用户id
 /// </summary>
 public int Id { get; set; }
 /// <summary>
 /// 用户姓名
 /// </summary>
 public string Name { get; set; }
 }

Install-Package NSwag.AspNetCore

  public void ConfigureServices(IServiceCollection services)
  {
   services.AddControllersWithViews();
   
   // Register the Swagger services
   services.AddSwaggerDocument()
  }

public void Configure(IApplicationBuilder app)
{
 app.UseStaticFiles();

 // Register the Swagger generator and the Swagger UI middlewares
 app.UseOpenApi();
 app.UseSwaggerUi3();

 app.UseMvc();
}

  public void ConfigureServices(IServiceCollection services)
  {
   //services.AddControllers();
   services.AddControllersWithViews();

   services.AddSwaggerDocument(config =>
   {
    config.PostProcess = document =>
    {
     document.Info.Version = "v1";
     document.Info.Title = "UserManageApp API";
     document.Info.Description = "A simple ASP.NET Core web API";
     document.Info.TermsOfService = "None";
     document.Info.Contact = new NSwag.OpenApiContact
     {
      Name = "张三",
      Email = string.Empty,
      Url = "https://example.com"
     };
     document.Info.License = new NSwag.OpenApiLicense
     {
      Name = "Use under LICX",
      Url = "https://example.com/license"
     };
    };
   });
  }