基本类型转换String

object TypeDemo15 {
  def main(args: Array[String]): Unit = {
    var a:Int = 5
    println((a+"").isInstanceOf[String])
  }
}

String 类型转基本类型

object TypeDemo16 {
  def main(args: Array[String]): Unit = {
    var s2:String = "12"

    var num1:Int = s2.toInt
    var num2:Float = s2.toFloat
    var num3:Double = s2.toDouble
    var num4:Long = s2.toLong

    println(s2.isInstanceOf[String])

    println(num1.isInstanceOf[Int])
    println(num2.isInstanceOf[Float])
    println(num3.isInstanceOf[Double])
    println(num4.isInstanceOf[Long])
  }
}

注意事项

object TypeDemo14 {
  def main(args: Array[String]): Unit = {
    var s4 = "12.5"

    println(s4.toInt)  // 此处会报错
    println(s4.toDouble.toInt)
  }

}