namespace JWTS.Services
{
  public interface IJWTService
  {
    /// <summary>
    /// 根据验证通过后的用户以及角色生成Token,以达到角色控制的作用
    /// </summary>
    /// <param name="userName"></param>
    /// <param name="role"></param>
    /// <returns></returns>
    string GetToken(string userName,string role);
  }
}

"TokenParameter": {
  "Issuer": "William", //这个JWT的签发主体(发行者)
  "Audience": "William", //这个JWT的接收对象
  "SecurityKey": "askalsnlkndhasnaslkasmadka"
 }

 　　public class TokenParameter
  　　{
    　　　　public string Issuer { get; set; }
    　　　　public string Audience { get; set; }
    　　　　public string SecurityKey { get; set; }
  　　}

using Microsoft.Extensions.Configuration;
using System;
using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;
using System.Text;
using Microsoft.IdentityModel.Tokens;

namespace JWTS.Services
{
  public class JWTService : IJWTService
  {
    private readonly TokenParameter _tokenParameter;
　　　　　　public JWTService(IConfiguration configuration)
    　　　　　　{
      　　　　　　　　_tokenParameter = configuration.GetSection("TokenParameter").Get<TokenParameter>();
    　　　　　　}
　　　　　/// <summary>
    /// JWT由三部分组成（Header、Payload、Signature）
    /// {Header}.{Payload}.{Signature}
    /// </summary>
    /// <param name="userName"></param>
    /// <param name="role"></param>
    /// <returns></returns>
    public string GetToken(string userName,string role)
    {
      Claim[] claims = new[]
      {
        new Claim(ClaimTypes.Name, userName),
        new Claim("NickName","Richard"),
        new Claim("Role",role)//传递其他信息
      };
      SymmetricSecurityKey key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_tokenParameter.SecurityKey));
      SigningCredentials creds = new SigningCredentials(key, SecurityAlgorithms.HmacSha256);
      /**
       * Claims (Payload)
        Claims 部分包含了一些跟这个 token 有关的重要信息。 JWT 标准规定了一些字段，下面节选一些字段:
        JWT会被加密，但是这部分内容任何人都可以读取，所以不要存放机密信息

        iss: The issuer of the token，token 是给谁的
        sub: The subject of the token，token 主题
        exp: Expiration Time。 token 过期时间，Unix 时间戳格式
        iat: Issued At。 token 创建时间， Unix 时间戳格式
        jti: JWT ID。针对当前 token 的唯一标识
        除了规定的字段外，可以包含其他任何 JSON 兼容的字段。
       * */
      var token = new JwtSecurityToken(
        issuer: _tokenParameter.Issuer,
        audience: _tokenParameter.Audience,
        claims: claims,
        expires: DateTime.Now.AddMinutes(10),//10分钟有效期
        signingCredentials: creds);
      string returnToken = new JwtSecurityTokenHandler().WriteToken(token);
      return returnToken;
    }
  }
}

public void ConfigureServices(IServiceCollection services) { services.AddScoped <IJWTService, JWTService> (); services.AddControllers(); }

using JWTS.Services;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging;

namespace JWTS.Controllers
{
  [Route("api/[controller]")]
  [ApiController]
  public class AuthenticationController : ControllerBase
  {
    #region 构造函数
    private ILogger<AuthenticationController> _logger;
    private IJWTService _iJWTService;
    private readonly IConfiguration _iConfiguration;
    public AuthenticationController(ILogger<AuthenticationController> logger,
      IConfiguration configuration
      , IJWTService service)
    {
      _logger = logger;
      _iConfiguration = configuration;
      _iJWTService = service;
    }
    #endregion

    /// <summary>
    /// 实际场景使用Post方法
    /// http://localhost:5000/api/Authentication/Login"name"></param>
    /// <param name="password"></param>
    /// <returns></returns>
    [Route("Login")]
    [HttpGet]
    public IActionResult Login(string name, string password)
    {
      //这里应该是需要去连接数据库做数据校验，为了方便所有用户名和密码写死了
      if ("william".Equals(name) && "123123".Equals(password))//应该数据库
      {
        var role = "Administrator";//可以从数据库获取角色
        string token = this._iJWTService.GetToken(name, role);
        return new JsonResult(new
        {
          result = true,
          token
        });
      }

      return Unauthorized("Not Register!!!");
    }
  }
}

using System;
using System.Text;
using API.Core.Models;
using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.IdentityModel.Tokens;

namespace API.Core
{
  public class Startup
  {
    private TokenParameter _tokenParameter;
    public IConfiguration Configuration { get; }
    public Startup(IConfiguration configuration)
    {
      Configuration = configuration;
      _tokenParameter = configuration.GetSection("TokenParameter").Get<TokenParameter>()"htmlcode">

　　 [ApiController]
  [Route("[controller]")]
  [Authorize]
  public class WeatherForecastController : ControllerBase
  {
    private static readonly string[] Summaries = new[]
    {
      "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
    };

    private readonly ILogger<WeatherForecastController> _logger;

    public WeatherForecastController(ILogger<WeatherForecastController> logger)
    {
      _logger = logger;
    }

    [HttpGet]
    public IEnumerable<WeatherForecast> Get()
    {
      var rng = new Random();
      return Enumerable.Range(1, 5).Select(index => new WeatherForecast
      {
        Date = DateTime.Now.AddDays(index),
        TemperatureC = rng.Next(-20, 55),
        Summary = Summaries[rng.Next(Summaries.Length)]
      })
      .ToArray();
    }
  }