可以在令牌中添加自定义声明，例如角色信息，并使用中间件将其提取到HttpContext.User中，以便在应用程序中的任何位置轻松访问它。

首先，在令牌中添加角色信息的示例代码如下：

var claims = new List { new Claim(JwtRegisteredClaimNames.Sub, userId), new Claim(JwtRegisteredClaimNames.Jti, Guid.NewGuid().ToString()), new Claim(JwtRegisteredClaimNames.Iat, DateTimeOffset.Now.ToUnixTimeSeconds().ToString(), ClaimValueTypes.Integer64), new Claim(ClaimTypes.Role, "Admin"), // 添加角色信息 };

var tokenDescriptor = new SecurityTokenDescriptor { Subject = new ClaimsIdentity(claims), Expires = DateTime.UtcNow.AddDays(7), SigningCredentials = new SigningCredentials(new SymmetricSecurityKey(key), SecurityAlgorithms.HmacSha256Signature) };

接下来，在Startup.cs文件中的ConfigureServices方法中配置JwtBearerOptions，以便将令牌中的角色信息添加到HttpContext.User中：

services.AddAuthentication(token => { token.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme; token.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme; }).AddJwtBearer(options => { options.RequireHttpsMetadata = false; options.SaveToken = true; options.TokenValidationParameters = new TokenValidationParameters { ValidateIssuerSigningKey = true, IssuerSigningKey = new SymmetricSecurityKey(key), ValidateIssuer = false, ValidateAudience = false }; options.Events = new JwtBearerEvents { OnTokenValidated = context => { if (context.Principal.Claims.FirstOrDefault(x => x.Type == ClaimTypes.Role) != null) { var roles = context.Principal.FindAll(ClaimTypes.Role).Select(x => x.Value).ToList(); // 将角色信息添加到HttpContext.User中并准备在应用程序中使用 var claimsIdentity = context.Principal.Identity as ClaimsIdentity; claimsIdentity.AddClaims(roles.Select(r => new Claim