1. 在Blazor项目中添加Refit NuGet包

2. 在Startup.cs文件中，添加以下代码：

using System.Net.Http;
using Refit;

public class Startup
{
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddScoped();

        services.AddRefitClient()
            .ConfigureHttpClient(c =>
            {
                c.BaseAddress = new Uri("https://example.com");
            })
            .AddHttpMessageHandler();
    }

    public void Configure(IApplicationBuilder app)
    {
        app.UseAuthentication();
        app.UseAuthorization();

        app.UseEndpoints(endpoints =>
        {
            endpoints.MapControllers();
        });
    }
}

public interface IMyApi
{
    [Get("/api/users")]
    Task> GetUsers();
}

public class User
{
    public int Id { get; set; }
    public string Name { get; set; }
}

public class BearerTokenHandler : DelegatingHandler
{
    private readonly IAccessTokenProvider _accessTokenProvider;

    public BearerTokenHandler(IAccessTokenProvider accessTokenProvider)
    {
        _accessTokenProvider = accessTokenProvider;
    }

    protected override async Task SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        var token = await _accessTokenProvider.RequestAccessToken();

        if (!string.IsNullOrWhiteSpace(token))
        {
            request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
        }

        return await base.SendAsync(request, cancellationToken);
    }
}

public interface IAccessTokenProvider
{
    Task RequestAccessToken();
}

3. 然后实现IAccessTokenProvider并返回令牌。例如，如果正在使用IdentityServer，则可以按照以下方式实现：

public class IdentityServerAccessTokenProvider : IAccessTokenProvider
{
    private readonly IHttpContextAccessor _httpContextAccessor;
    private readonly IHttpClientFactory _httpClientFactory;

    public IdentityServerAccessTokenProvider(IHttpContextAccessor httpContextAccessor, IHttpClientFactory httpClientFactory)
    {
        _httpContextAccessor = httpContextAccessor;
        _httpClientFactory = httpClientFactory;
    }

    public async Task RequestAccessToken()
    {
        var accessToken = await _httpContextAccessor.HttpContext.GetTokenAsync("access_token");

        if (string.IsNullOrWhiteSpace(accessToken))
        {
            var client = _httpClientFactory.CreateClient("IdentityServer");
            var disco = await client.GetDiscoveryDocumentAsync("https://example.com");
            if (disco.IsError)
            {
                throw new Exception(disco.Error);
            }

            var tokenClient = _httpClientFactory.CreateClient("IdentityServer");
            var tokenResponse = await tokenClient.RequestClientCredentialsTokenAsync(new ClientCredentialsTokenRequest
            {
                Address = disco.TokenEndpoint,
                ClientId = "your_client_id",