没有依赖注入的DOA模式(DOA pattern without dependency injection)

 在我们公司，我们几乎在每个项目中都使用DAO模式。 这有一些优点和缺点，但问题不在于此。 我们刚刚启动了另一个项目，但与其他项目相比，它非常简单，并且不是基于DI框架。 只是一个在云上运行的简单servlet。 
 
 我的问题是：当DI不可用时如何实现DAO模式。 如何在以后模拟DAO？ 他们必须在某个服务类内部初始化。 在测试期间使用反射并用模拟替换真正的DAO是一个好习惯吗？ 另一种观点是使用factoryDAO ..但如何使用工厂返回模拟对象？ 

In our company we use DAO pattern in almost every project. This has some pros and cons but the question is not about that. We just started another project but in comparison with the others it is very simple and is not based on a DI framework. Just a simple servlet run on a cloud. 
 
My question is: How to implement DAO pattern when DI is not available. How to mock DAOs later? They have to initialized somewhere probably inside a service class. Is it a good practice to use reflection during the tests and replace real DAOs with mocks? Another view is to use factoryDAO .. but how to use factory to return mock objects?

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