scala - 为什么嵌套的 Java 类不能从 Scala 导入？

Question

我应该如何使用 模拟嵌套的 Java 类蛤蜊 ，尤其是当所说的嵌套 Java 类来自第三方库时？

鉴于以下来源:

src/main/java/Outer.java

/**
  * Outer class that offers a Nested class inaccessible from Scala :(
  */
 public class Outer {
   public class Nested {

   }
 }

src/main/java/UseNestedJavaClassFromJava.java

public class UseNestedJavaClassFromJava {
   private Outer.Nested nested;
 }

src/main/scala/ImportNestedJavaClass.scala

// TODO uncomment the below line to break the build
//import Outer.Nested

取消注释 scala 导入行会导致编译失败，同时编译 UseNestedJavaClassFromJava.java 工作正常。

带有 gradle 的完整最小示例: https://github.com/billyjf/async-http-client-gradle-scala .

显然这在下面的问题中已经有所解决，但是仅仅为了测试利用带有嵌套 Java 类的 Java 库的 Scala 代码而诉诸 Java 粘合代码或反射技巧对我来说似乎有点不合理，真的没有其他解决方案吗？ ?

Scala can't access Java inner class?

Answer 1

我终于找到了使用 Mockito 的解决方案:

import org.mockito.Mockito
import org.scalamock.scalatest.MockFactory
import org.scalatest.mockito.MockitoSugar
import org.scalatest.{FlatSpec, Matchers}

class OuterNestedTest extends FlatSpec with MockFactory with Matchers with MockitoSugar {
  "Nested Java class" should "be mockable using Mockito from within a scalatest" in {
    val mockedNestedJavaClass = Mockito.mock(classOf[Outer#Nested])

    Mockito.when(mockedNestedJavaClass.methodWithAParam("some value"))
      .thenReturn("mocked", Nil: _*)

    mockedNestedJavaClass.methodWithAParam("some value") shouldBe "mocked"
  }
}