要在Blazor中刷新令牌以获取JWT令牌，您可以按照以下步骤进行操作：

1. 创建一个名为TokenRefresher的类，用于管理刷新令牌的逻辑。

public class TokenRefresher
{
    private readonly HttpClient httpClient;
    private readonly IAccessTokenProvider accessTokenProvider;
    private Timer timer;
    
    public TokenRefresher(HttpClient httpClient, IAccessTokenProvider accessTokenProvider)
    {
        this.httpClient = httpClient;
        this.accessTokenProvider = accessTokenProvider;
    }

    public async Task StartTokenRefresh()
    {
        var accessToken = await accessTokenProvider.RequestAccessToken();
        var tokenExpirationTime = accessTokenProvider.TokenExpiresAt;

        var refreshTokenInterval = tokenExpirationTime.Subtract(DateTime.UtcNow.AddMinutes(1));

        timer = new Timer(async _ =>
        {
            var newAccessToken = await httpClient.GetFromJsonAsync("api/refresh");
            accessTokenProvider.SetAccessToken(newAccessToken);
        }, null, refreshTokenInterval, refreshTokenInterval);
    }

    public void StopTokenRefresh()
    {
        timer?.Dispose();
    }
}

2. 在Program.cs文件中注册TokenRefresher类。

builder.Services.AddScoped();

3. 在Startup.cs文件中配置JWT身份验证。

public void ConfigureServices(IServiceCollection services)
{
    // ...

    services.AddAuthentication(options =>
    {
        options.DefaultScheme = JwtBearerDefaults.AuthenticationScheme;
        options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
    })
    .AddJwtBearer(options =>
    {
        options.TokenValidationParameters = new TokenValidationParameters
        {
            ValidateIssuer = true,
            ValidateAudience = true,
            ValidateLifetime = true,
            ValidateIssuerSigningKey = true,
            ValidIssuer = Configuration["Jwt:Issuer"],
            ValidAudience = Configuration["Jwt:Audience"],
            IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(Configuration["Jwt:SecretKey"]))
        };
    });

    // ...
}

4. 在需要进行刷新令牌的页面或组件中注入TokenRefresher类。

@inject TokenRefresher tokenRefresher

@code {
    protected override async Task OnInitializedAsync()
    {
        await tokenRefresher.StartTokenRefresh();
    }

    public void Dispose()
    {
        tokenRefresher.StopTokenRefresh();
    }
}

请确保替换代码中的api/refresh为您服务端提供刷新令牌的API路由。另外，还要确保您正确配置了JWT身份验证的相关参数，如Jwt:Issuer，Jwt:Audience和Jwt:SecretKey。