依赖注入：对接多Azure存储实例如何避免重复定义接口与实现类？

1. 复用统一接口与实现 #

删除所有带数字后缀的重复接口、实现类，仅保留一套通用定义：

通用接口定义 #

public interface IAzureBlobStorage
{
    string AzureBlobContainerName { get; }
    string StorageName { get; }

    public Task<Stream> DownloadStreamAsyns(string fileName);
    public Task Upload(string fileId, Stream stream);
}

通用实现类定义 #

public class AzureBlobStorage : IAzureBlobStorage
{
    private BlobContainerClient _client;
    private string _containerName;
    private string _storageName;
    public string StorageName => _storageName;
    public string AzureBlobContainerName => _containerName;

    public AzureBlobStorage(BlobContainerClient client, string containerName, string storageName)
    {
        _client = client;
        _containerName = containerName;
        _storageName = storageName;
    }

    public async Task<Stream> DownloadStreamAsyns(string fileName)
    {
        return await _client.GetBlobClient(fileName).OpenReadAsync();
    }

    public async Task Upload(string fileId, Stream stream)
    {
        await _client.GetBlobClient(fileId).UploadAsync(stream);
    }
}

2. 通用服务注册 #

方案A：.NET 8+ 键控服务（推荐） #

.NET 8开始原生支持按键注入服务，不用额外实现工厂：

编写自动注册扩展方法

public static IServiceCollection AddAllAzureStorages(this IServiceCollection services, IConfiguration configuration)
{
    // 读取所有存储配置节点
    var storageSections = configuration.GetSection("AzureBlobStorageConfiguration:Storages").GetChildren();
    foreach (var section in storageSections)
    {
        var options = new ABlobStorageConfigurationOptionsDTO();
        section.Bind(options);
        // 以存储配置的节点名（Storage1/Storage2/Storage3）作为键注册服务
        services.AddKeyedTransient<IAzureBlobStorage, AzureBlobStorage>(section.Key, (isp, _) =>
        {
            var client = new BlobServiceClient(options.ConnString);
            var container = client.GetBlobContainerClient(options.AzureBlobContainerName);
            return new AzureBlobStorage(container, options.AzureBlobContainerName, options.StorageName);
        });
    }
    return services;
}

启动类中调用注册

在Startup.cs/Program.cs中只需调用一次即可注册所有配置的存储实例：

services.AddAllAzureStorages(configuration);

业务中注入使用

在控制器/服务中按存储名注入对应实例即可：

public class YourController : Controller
{
    private readonly IAzureBlobStorage _storage1;
    private readonly IAzureBlobStorage _storage2;

    public YourController(
        [FromKeyedServices("Storage1")] IAzureBlobStorage storage1,
        [FromKeyedServices("Storage2")] IAzureBlobStorage storage2)
    {
        _storage1 = storage1;
        _storage2 = storage2;
    }
}

方案B：.NET 7及以下版本 工厂模式 #

如果使用不支持键控服务的低版本.NET，可通过工厂类实现实例获取：

定义存储工厂

public interface IAzureBlobStorageFactory
{
    IAzureBlobStorage GetStorage(string storageName);
}

public class AzureBlobStorageFactory : IAzureBlobStorageFactory
{
    private readonly IConfiguration _configuration;

    public AzureBlobStorageFactory(IConfiguration configuration)
    {
        _configuration = configuration;
    }

    public IAzureBlobStorage GetStorage(string storageName)
    {
        var options = new ABlobStorageConfigurationOptionsDTO();
        _configuration.GetSection($"AzureBlobStorageConfiguration:Storages:{storageName}").Bind(options);
        var client = new BlobServiceClient(options.ConnString);
        var container = client.GetBlobContainerClient(options.AzureBlobContainerName);
        return new AzureBlobStorage(container, options.AzureBlobContainerName, options.StorageName);
    }
}

注册工厂

services.AddSingleton<IAzureBlobStorageFactory, AzureBlobStorageFactory>();

业务中使用

public class YourController : Controller
{
    private readonly IAzureBlobStorage _storage1;
    private readonly IAzureBlobStorage _storage2;

    public YourController(IAzureBlobStorageFactory storageFactory)
    {
        _storage1 = storageFactory.GetStorage("Storage1");
        _storage2 = storageFactory.GetStorage("Storage2");
    }
}

优化后效果 #

• 新增存储实例仅需在appsettings.json中添加对应配置节点，无需新增任何接口、实现类和注册代码
• 完全消除重复代码，后续调整存储通用逻辑仅需修改一次
• 存储数量无上限，可根据配置灵活扩展

内容的提问来源于stack exchange，提问作者jrywin