在Program.cs app.UseStaticFiles 这样写

var provider = new FileExtensionContentTypeProvider();
provider.Mappings[".apk"] = "application/vnd.android.package-archive";
provider.Mappings[".flac"] = "audio/flac,audio/x-flac";
app.UseStaticFiles(new StaticFileOptions
{
    ContentTypeProvider = provider,
    OnPrepareResponse = (c) => {
        c.Context.Response.Headers.Add("Access-Control-Allow-Origin", "*");
    }
});