app.UseStaticFiles();

            //设置实际目录与虚拟目录  
            app.UseStaticFiles(new StaticFileOptions
            {
                FileProvider = new PhysicalFileProvider(Path.Combine(Directory.GetCurrentDirectory(), @"wwwroot/Files")),
                RequestPath = new PathString("/jfiles"),
             
                //设置Android APK 下载
                ContentTypeProvider = new FileExtensionContentTypeProvider(new Dictionary<string, string>
                {
                    { ".apk","application/vnd.android.package-archive"},
                    { ".nupkg","application/zip"}
                })
            });