Spring注入kotlin中通用接口实现的列表 [英] Spring inject list of generic interface implementations in kotlin

问题描述

免责声明：对于Kotlin来说，这可能是一个易于解决的问题或被误解的基础知识。

Disclaimer: New to Kotlin, may be a easy to solve issue or misunderstood basics.

我正尝试在其中插入特定接口的Spring实现列表。

I am trying to inject a List of a specific interface's Spring implementations, in a regular java class this have been easy like this:

@Autowired
List<IMyClass> myClassList;

但是在Kotlin中，执行以下操作会给我一个错误

But in Kotlin doing the following gives me a error

@Autowired
lateinit private var myClassList: List<IMyClass<Any>>

// No beans of '? extends IMyClass<Object>' or 'List<? extends IMyClass<Object>>' types found

这样做：

@Autowired
lateinit private var myClassList: List<IMyClass<*>>

进行注入工作，但不允许我使用接口中定义的函数通用对象作为输入

Makes the injection work but doesn't allow me to use a function defined in the interface that takes a generic object as input

// Out-projected type 'IMyClass<*>' prohibits the use of 'public abstract fun myFunction(obj: T!): T! defined in com.path.IMyClass'

那么我应该如何解决呢？

So how am I supposed to solve this? Is it easier to rewrite the interface in Kotlin with some specific syntac?

推荐答案

您在Java中所做的事情只是使用隐式操作？通配符。因此，这里有2种方式：

Thing you're doing in Java is just using implicit wildcard. So you have 2 ways here:

1. 尝试重构API并注入 List< IMyClass<的列表？扩展SomeInterface>>>


2. 使用注入的 List< IMyClass< *>> 但将其强制转换明确显示您需要的东西，即 myClassList as List< IMyClass< Any>>

1. Try to refactor API and inject list of List<IMyClass<? extends SomeInterface>>
2. Use injected List<IMyClass<*>> but cast it explicitly to thing you need, i.e. myClassList as List<IMyClass<Any>>

在这里，科特林的抹除更为明确。如果您不知道那里有什么类型，我们就不能保证您的代码能正常工作，因为kotlin中有这样的类型： Nothing ，而该实例不能存在。

Thing here is kotlin's erasure is more explicit. If you don't know what type is there — we can't guarantee your code will work, because there is such type in kotlin as Nothing, instance of which can't exist.

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