c#设计模式——为多个数据源设计的最佳方式
本文关键字:最佳 方式 设计模式 数据源 | 更新日期: 2023-09-27 18:05:59
我目前有一个ASP。. Net MVC 5应用程序,使用3个外部数据源(调用外部api,响应被反序列化,并映射到业务poco)。
该应用目前使用SimpleInjector将每个数据源的具体存储库注入业务逻辑层以供使用。
问题是,随着更多数据源的添加(可能是20-30),构造函数将会非常庞大,注入所有这些存储库似乎很麻烦。
是否有更好的模式/方法来使用所有的数据源而不是使用不同的存储库?
是facade还是其他模式更合适?
非常通用的例子:
public class MyObject(){
public IEnumerable<Cat> Cats { get; set; }
public IEnumerable<Dog> Dogs { get; set; }
public IEnumerable<Fish> Fish { get; set; }
}
public class BusinessLogic{
private readonly ISourceARepository _sourceA;
private readonly ISourceBRepository _sourceB;
private readonly ISourceCRepository _sourceC;
public BusinessLogic(ISourceARepository sourceA, ISourceBRepository sourceB, ISourceCRepository sourceC){
_sourceA = sourceA;
_sourceB = sourceB;
_sourceC = sourceC;
}
private Dog MapSourceARecordToDog(SourceARecord record){
var result = new Dog();
if(record != null){
result.Name = record.NameField;
result.Age = record.Age;
}
return result;
}
private Cat MapSourceBRecordToCat(SourceBRecord record){
var result = new Cat();
if(record != null){
result.Name = record.NameField;
result.Weight = record.WeightField;
}
return result;
}
private Fish MapSourceCRecordToFish(SourceCRecord record){
var result = new Fish();
if(record != null){
result.ID = record.IDField;
result.Name = record.NameField;
}
return result;
}
public MyObject GetResults(){
var result = new MyObject();
result.Dogs = _sourceA.GetAll().Select(MapSourceARecordToDog).ToList();
result.Cats = _sourceB.GetAll().Select(MapSourceBRecordToCat).ToList();
result.Fish = _sourceC.GetAll().Select(MapSourceCRecordToFish).ToList();
return result;
}
}
public class SourceARespository : ISourceARepository{
public IEnumerable<SourceAResult> GetAll(){
return new List<SourceAResult>();
}
}
public class SourceBRespository : ISourceBRepository{
public IEnumerable<SourceBResult> GetAll(){
return new List<SourceBResult>();
}
}
public class SourceCRespository : ISourceCRepository{
public IEnumerable<SourceCResult> GetAll(){
return new List<SourceCResult>();
}
}
更新:这不是构造函数疯狂问题的重复,因为在这种情况下,类需要许多不同的数据源,但仍然只有一个职责。因此,它有自己的解释和答案。
您应该只向依赖的消费者中注入一个实体存储库。您还可以选择使用业务类中介来调整存储库。
:
根据问题和问题陈述中提供的信息,这里有一个可能的解决方案。像这样定义您的核心基础结构:
public abstract class Entity<TEntity, TDomainObject, TIRepository>
where TEntity : Entity<TEntity, TDomainObject, TIRepository>
where TDomainObject : Entity<TEntity, TDomainObject, TIRepository>.BaseDomainObject, new()
where TIRepository : Entity<TEntity, TDomainObject, TIRepository>.IBaseRepository
{
public class BaseDomainObject {}
public interface IBaseRepository
{
IEnumerable<TDomainObject> GetAll();
IEnumerable<T> GetAllMapped<T>(Func<TDomainObject, T> mapper);
}
public class BaseRepository : IBaseRepository
{
public IEnumerable<TDomainObject> GetAll()
{
return new List<TDomainObject>();
}
public IEnumerable<T> GetAllMapped<T>(Func<TDomainObject, T> mapper)
{
return this.GetAll().Select(mapper);
}
}
}
像这样定义你的源实体:
public class SourceA : Entity<SourceA, SourceA.DomainObject, SourceA.IRepository>
{
public class DomainObject : BaseDomainObject
{
public string Name;
public int Age;
}
public interface IRepository : IBaseRepository {}
public class Repository : BaseRepository, IRepository {}
}
public class SourceB : Entity<SourceB, SourceB.DomainObject, SourceB.IRepository>
{
public class DomainObject : BaseDomainObject
{
public string Name;
public decimal Weight;
}
public interface IRepository : IBaseRepository {}
public class Repository : BaseRepository, IRepository {}
}
public class SourceC : Entity<SourceC, SourceC.DomainObject, SourceC.IRepository>
{
public class DomainObject : BaseDomainObject
{
public Guid Id;
public string Name;
}
public interface IRepository : IBaseRepository {}
public class Repository : BaseRepository, IRepository {}
}
然后像这样定义一个ISourceRepositoryContext
接口并在这里添加每个源存储库接口:
public interface ISourceRepositoryContext
{
SourceA.IRepository SourceARepository { get; }
SourceB.IRepository SourceBRepository { get; }
SourceC.IRepository SourceCRepository { get; }
}
然后定义接口的默认实现:
public class DefaultSourceRepositoryContext : ISourceRepositoryContext
{
public SourceA.IRepository SourceARepository => new SourceA.Repository();
public SourceB.IRepository SourceBRepository => new SourceB.Repository();
public SourceC.IRepository SourceCRepository => new SourceC.Repository();
}
定义结果传输对象:
public class Dog
{
public string Name;
public int Age;
}
public class Cat
{
public string Name;
public decimal Weight;
}
public class Fish
{
public Guid Id;
public string Name;
}
public class MyObject
{
public IEnumerable<Cat> Cats { get; set; }
public IEnumerable<Dog> Dogs { get; set; }
public IEnumerable<Fish> Fish { get; set; }
}
然后在您的BusinessLogic类中使用ISourceRepositoryContext:
public class BusinessLogic
{
protected ISourceRepositoryContext repositories;
public BusinessLogic(ISourceRepositoryContext repositories)
{
this.repositories = repositories;
}
public MyObject GetResults(string param1)
{
return new MyObject()
{
Dogs = this.repositories.SourceARepository.GetAllMapped
(domainObject=>new Dog
{
Age = domainObject.Age,
Name = domainObject.Name
}),
Cats = this.repositories.SourceBRepository.GetAllMapped
(domainObject=>new Cat
{
Name = domainObject.Name,
Weight = domainObject.Weight
}),
Fish = this.repositories.SourceCRepository.GetAllMapped
(domainObject=>new Fish
{
Id = domainObject.Id,
Name = domainObject.Name
}),
};
}
}
我已经确认上面的代码可以在c# 6.0下编译。
我建议将IRepository更改为实体中的IBusiness,并将数据访问关注点分离到只有IBusiness实现者通过其构造函数接收的IDataAccess接口中。然后将ISourceRepositoryContext更改为ISourceEntities,并将该接口中的IRepository属性更改为IBusiness属性。
BusinessLogic类是我真正关心的部分。你确定这门课不会给你带来太多麻烦吗?这应该是UoW课程吗?
关于基于类似技术的更完整的解决方案,请查看我对另一个问题的回答:.NET管理层关系