[英]Scala object extends Java class static field
I'm would like to know how could I inherent static field from Java class in Scala. 我想知道Scala中Java类的固有静态字段怎么样。
Here is a Java example, if I a class named ClassFromJava, I could extend it, add some static field, and use the subclass to access the VERSION field. 这是一个Java示例,如果我是一个名为ClassFromJava的类,我可以扩展它,添加一些静态字段,并使用子类来访问VERSION字段。
public class ClassFromJava {
public static int VERSION = 1;
}
public class ClassFromJavaSub extends ClassFromJava {
public static String NOTE = "A note";
}
public class Test {
public static void main (String [] args) {
System.out.println (ClassFromJavaSub.VERSION); // This works.
}
}
But if I want extends ClassFromJava in Scala, and add some constant value, it seems not work. 但是,如果我想在Scala中扩展ClassFromJava,并添加一些常量值,它似乎不起作用。
object ClassFromScala extends ClassFromJava {
val NOTE = "A Note"
}
object Test {
def main (args: Array[String]) {
// This line won't compile
// ClassFromScala has no value VERSION.
println (ClassFromScala.VERSION)
}
}
What should I do if I would like ClassFromScala also has the VERSION variable? 如果我想ClassFromScala也有VERSION变量,我该怎么办?
object ClassFromScala extends ClassFromJava {
def VERSION = ClassFromJava.VERSION
}
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