使用类参数分配字段值 [英] Using class parameters to assign field value

问题描述

我是scala的新手，想使用类参数将值分配给相同的字段。在Java中，我们在构造函数中执行类似的操作：

I'm new to scala and would like to use class parameters to assign the value to a field of the same. In Java, we do similar thing within a constructor:

public class Test{

    private final int value;

    public Test(int value){
        this.value = value;
    }
}

现在，我尝试在 Scala ：

class Test(value: Int){
   val value = ..WHAT..value //Is there a way to assign a parameter value to a field with the same name?
}

object Test{
   def testMethod = //access value and do something with it.
}

我们可以做一些类似于Java的事情吗？

Can we do something similar to what we can in do in Java?

推荐答案

Scala提供了创建此类成员的较短语法-只需添加关键字 val 在类参数列表中的参数名称之前。您还可以添加修饰符（例如 private ）：

Scala provides a shorter syntax for creating such a member - just add the keyword val before the argument name in the class parameter list. You can also add a modifier (e.g. private):

scala> :paste
// Entering paste mode (ctrl-D to finish)

class Test(private val value: Int)

object Test {
  def testMethod(t: Test) = t.value
}

// Exiting paste mode, now interpreting.

defined class Test
defined module Test

scala> Test.testMethod(new Test(5))
res1: Int = 5

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