scala中对象私有数据_Scala中的对象投射

痛定思痛。 2023-03-05 09:38 18阅读 0赞

scala中对象私有数据

**Object casting** is changing the object's type from one type to another type. Instances or [objects in Scala][] are casted using the asInstanceOf method in Scala.

**对象转换**正在将对象的类型从一种类型更改为另一种类型。 [Scala][objects in Scala]中的实例或[对象使用Scala][objects in Scala]中的asInstanceOf方法强制转换 。

**asInstanceOf Method**

**asInstanceOf方法**

The *asInstanceOf* method in Scala is used to cast the instance of one type into another type. It is a concrete method of *Any* class which is the root of [Scala class][] hierarchy so it is by default inherited.

Scala中的*asInstanceOf*方法用于将一种类型的实例转换为另一种类型。 它是*Any*类的具体方法，它是[Scala类][Scala class]层次结构的根，因此默认情况下是继承的。

**Syntax:**

**句法：**

def asInstance[objecttype] : objecttype

The method takes an *objecttype* as a parameter and returns the casted object.

该方法将对象*类型*作为参数，并返回*强制*转换的对象。

The syntax used for **casting object** using object casting using *asInstanceOf* method,

使用*asInstanceOf*方法进行对象转换的**对象**的语法，

object.asInstanceof[type]

## 演示对象投射的程序 **(**Program to illustrate the object casting**)** ##

**Program 1:** Casting an object of numeric type (int) to non-numeric type (char).

**程序1：**将数字类型(int)的对象转换为非数字类型(char)。

object myObject {
        
     def flaotConvertor(a: Int): Char = {
        
      return a.asInstanceOf[Char]
     }
    
     def main(args: Array[String]) {
        
      val obj1 = 99
      println("Initial value is " + obj1 + ", type of value is " + obj1.getClass)
      val obj2 = flaotConvertor(obj1)
      println("Object casting Done!")
      println("Value after casting is " + obj2 + ", type of value is " + obj2.getClass)
     }
    }

**Output:**

**输出：**

Initial value is 99, type of value is int
    Object casting Done!
    Value after casting is c, type of value is char

**Explanation:**

**说明：**

In the above code, we have created an instance of integer type and then cast it to another instance of type char. The output we got is the character converted for the integer value taking the integer value as [ASCII value][]. For this, we have created a method named *flaotConvertor()* which took the object as a parameter and return the object of another type. In the function, we have used the asInstanceOf method. To find the type of object we have used the method *getClass*.

在上面的代码中，我们创建了一个整数类型的实例，然后将其强制转换为char类型的另一个实例。 我们得到的输出是将整数值转换为以[ASCII值][ASCII value]作为整数值的[字符][ASCII value] 。 为此，我们创建了一个名为*flaotConvertor()*的方法，该方法将对象作为参数并返回另一种类型的对象。 在函数中，我们使用了asInstanceOf方法。 为了找到对象的类型，我们使用了*getClass*方法。

**Program 2:** Casting an object from one numeric type (int) to another numeric type (float).

**程序2：**将对象从一种数字类型(int)转换为另一种数字类型(float)。

object myObject {
        
     def flaotConvertor(a: Int): Float = {
        
      return a.asInstanceOf[Float]
     }
    
     def main(args: Array[String]) {
        
      val a = 10
      println("Initial value is " + a + ", type of value is " + a.getClass)
      val b = flaotConvertor(a)
      println("Object casting Done!")
      println("Value after casting is " + b + ", type of value is " + b.getClass)
     }
    }

**Output:**

**输出：**

Initial value is 10, type of value is int
    Object casting Done!
    Value after casting is 10.0, type of value is float

Explanation:

说明：

In the above code, we have created an instance of integer type and then cast it to another instance of type float. For this, we have created a method named *flaotConvertor()* which took the object as a parameter and return the object of another type. In the function, we have used the *asInstanceOf* method. To find the type of object we have used the method *getClass*.

在上面的代码中，我们创建了一个整数类型的实例，然后将其强制转换为float类型的另一个实例。 为此，我们创建了一个名为*flaotConvertor()*的方法，该方法将对象作为参数并返回另一种类型的对象。 在函数中，我们使用了*asInstanceOf*方法。 为了找到对象的类型，我们使用了*getClass*方法。

> 翻译自: [https://www.includehelp.com/scala/object-casting.aspx][https_www.includehelp.com_scala_object-casting.aspx]

scala中对象私有数据

[objects in Scala]: https://www.includehelp.com/scala/objects-in-scala.aspx
[Scala class]: https://www.includehelp.com/scala/classes-and-objects-in-scala.aspx
[ASCII value]: https://www.includehelp.com/ascii-table.aspx
[https_www.includehelp.com_scala_object-casting.aspx]: https://www.includehelp.com/scala/object-casting.aspx