解耦问题 - 改进和替代方案

Question

我正在学习 SOLID 原则——尤其是控制反转-DI-解耦，当我在审查我的一个代码时，我注意到这种方法（见下文）引起了我的注意。

此代码将由任何需要读取 json 文件的方法调用，接受将用于查找 json 文件的字符串值。但是正如您所看到的（我简化了代码 - 为了本主题排除了异常处理），我不确定从哪里开始（有很多初始化或依赖项？？发生了，我不确定在哪里开始）。

这种方法/场景可以作为一个很好的选择开始吗？你认为我应该保留哪个？并且需要解耦？

谢谢。

public async Task<object> ReadJsonByKey(string jsonPath, string jsonKey)

{

    // First - is it okay to have an initialization at this stage?

    var value = new object();     

    // Second - is this fine to have this in the scope of this method?

    using (TextReader reader = File.OpenText(jsonPath))  

    {

        // Third -  Calling Jobject that accepts new instance of JsonTextReader

        var jObject = await JObject.LoadAsync(new JsonTextReader(reader)); 

        obj = jObject.SelectToken(jsonKey);

    }

    return value;

}

我问这个的原因也是因为（基于标准）松散耦合的东西可以很容易地测试 - 即单元测试

[UnitTestSuite]

    [TestCase1]

        // Method should only be able to accept ".json" or ".txt" file

    [TestCase2]

        // JsonPath file is valid file system

    [TestCase3]

        // Method should be able to retrieve a node value based from a specific json and key

    [TestCase4]

        // Json-text file is not empty

Answer 1

看起来您正试图将基础设施问题与应用程序代码分离。假设是这种情况，您需要一个负责读取数据的类：public interface IDataReader{&nbsp; &nbsp; &nbsp;Task<object> ReadJsonByKey(string jsonPath, string jsonKey)}其实现将是您上面的代码：public class DataReader : IDataReader{&nbsp; &nbsp; public async Task<object> ReadJsonByKey(string jsonPath, string jsonKey)&nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; // First - is it okay to have an initialization at this stage?&nbsp; &nbsp; &nbsp; &nbsp; var value = new object();&nbsp; &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; &nbsp; // Second - is this fine to have this in the scope of this method?&nbsp; &nbsp; &nbsp; &nbsp; using (TextReader reader = File.OpenText(jsonPath))&nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; // Third -&nbsp; Calling Jobject that accepts new instance of JsonTextReader&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; var jObject = await JObject.LoadAsync(new JsonTextReader(reader));&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; obj = jObject.SelectToken(jsonKey);&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; return value;&nbsp; &nbsp; }}但是，这个类现在同时进行文件读取和反序列化，因此您可以进一步分为：public class DataReader : IDataReader{&nbsp; &nbsp; IDeserializer _deserializer;&nbsp; &nbsp; public DataReader(IDeserializer deserializer)&nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; _deserializer = deserializer;&nbsp; &nbsp; }&nbsp; &nbsp; public async Task<object> ReadJsonByKey(string jsonPath, string jsonKey)&nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; var json =&nbsp; File.ReadAllText(jsonPath);&nbsp; &nbsp; &nbsp; &nbsp; return _deserializer.Deserialize(json, jsonKey);&nbsp; &nbsp; }}这意味着现在可以IDeserializer独立于文件系统依赖项进行单元测试。但是，主要的好处应该是您现在可以IDataReader在对应用程序代码进行单元测试时模拟实现。