快学Scala 第十三课 （类型层级，对象相等性）

Scala 类型层级：

对象相等性：

和Java一样要重写equals方法和hashcode方法

class Student(val id: Int, val name: String) {
  override def equals(other: Any) = {
    val that = other.asInstanceOf[Student]
    if (that == null) false
    else id == that.id && name == that.name
  }

  override def hashCode = 13 * id.hashCode() + 17 * name.hashCode()

}

object TestCase {
    def main(args: Array[String]): Unit = {

      val s1 = new Student(1,"Sky")
      val s2 = new Student(1,"Sky")

      println(s1.equals(s2))
      println(s1 == (s2))

  }

}

返回结果：

true

true