通过“精细"访问内部类方法.使用Scala类和Java的Java语法目的 [英] Access inner class method with "fine" syntax in Java using Scala class & object

问题描述

我有以下scala示例:

I have the following scala example:

class Nested {}
object Nested {
  class Inner {}
  object Inner {
    def x = 321
  }
}

使用JUnit测试专门测试我可以执行Nested.Inner.x()并在没有Nested.Inner$.MODULE$.x()的情况下自由调用该方法:

With a JUnit test to test specifically that I can do Nested.Inner.x() and call the method freely without the Nested.Inner$.MODULE$.x():

  import static junit.framework.Assert.*;
  import org.junit.Test;

  public class TestFromJava {

  @Test
  public void accessTest() {
    assertEquals(321, Nested.Inner.x());
  }
}

这可以编译，但是在运行测试的那一刻，我得到了(sbt test):

This compiles, but at the moment of running the test, I am getting (sbt test):

[error] TestFromJava.java:8: cannot find symbol
[error]   symbol:   method x()
[error]   location: class Nested.Inner
[error] Nested.Inner.x

如何从Scala语法和不使用可怕的$中受益?也许这是该语言在生成object实例时的一种功能.

How can I benefit from both Scala syntax and not using the horrible $? Maybe it is a feature of the language as how it generates the object instances.

推荐答案

从Java调用时，您必须限定单例object访问权限，如

You have to qualify singleton object access when calling from Java, as explained in this question.

在您的情况下

Nested.Inner$.MODULE$.x()

这篇关于通过“精细"访问内部类方法.使用Scala类和Java的Java语法目的的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！