我想要写入的字符串表示case class Grp
trait Value
// define these in different files if you want
case class Student(value: String) extends Value
case class Employee(value: Double) extends Value
case class Department(value: Int) extends Value
case class Element(key: String, value: Value)
case class Grp (elements: List[Element] = Nil) extends Value {
def add (key: String, value: Value): Grp = Grp(this.elements ++ List(Element(key, value)))
}
val s= Grp()
.add("2", Student("abc"))
.add("3", Employee(100.20))
.add("4", Department(10))
.add("5", Grp().add("2", Student("xyz"))) // nested group
我想打印由“=”分隔的键值对
print(s.productIterator.mkString(""))