c# - 如何在 ASP.NET Core 中使用 XML 或 JSON 作为数据源

Question

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Answer 1

无论您决定使用哪种数据存储技术，我都建议您将数据访问抽象为某些接口(interface)，这样您的应用程序就不会绑定(bind)到特定的实现。如果您将来决定这样做，这将使您能够更轻松地切换到其他一些存储技术。

因此，如果您想使用内存数据存储，那为什么不呢:

public interface IDataStore
{
    IQueryable<MyModel> Get();

    void Add(MyModel model);

    ...
}

可以这样实现:

public JsonDatastore : IDataStore
{
    private readonly string dataFile;
    private readonly IList<MyModel> data;

    public Datastore(string dataFile)
    {
        this.dataFile = dataFile;
        this.data = JsonConvert.DeserializeObject<IList<MyModel>>(File.ReadAllText(dataFile));
    }

    public IQueryable<MyModel> Get()
    {
        return this.data.AsQueryable();
    }

    public void Add(MyModel model)
    {
        // If you want a lock free implementation you may consider
        // an algorithm which will only notify some underlying thread
        // that a change has been made to the underlying structure and
        // it will take care of saving those changes to the file system
        // This way it is guaranteed that only one thread is writing
        // to the file while the changes can be made in memory quite fast
        // (using a ConcurrentBag<T> instead of a list for example)

        lock (this)
        {
            // Make sure that only one thread is updating the file
            this.data.Add(model);
            string json = JsonConvert.SerializeObject(this.data);
            File.WriteAllText(this.dataFile, json);
        }
    }
}

现在最后一个重要的一点是确保将依赖注入(inject)容器中的 Datastore 生命周期实例配置为 singleton。