case class和case object模式匹配实验
/**
* @Author Joe_Liang
* @Date 2021/10/18 15:59
* @Version 1.0
*/
case class SubmitTask(id:String,name:String)
case class HeartBeat(time:Long)
case object CheckTimeOutTask
object caseTest {
def main(args: Array[String]): Unit = {
val arr = Array(CheckTimeOutTask,SubmitTask("123","zs"),HeartBeat(12333333))
for(i <- 0 until 10) {
arr(Random.nextInt(arr.length)) match {
case SubmitTask(id,name) => println(s"${id} ${name}")
case HeartBeat(time) => println(time)
case CheckTimeOutTask => println("checktimeouttask")
}
}
}
}
显示如下：
123 zs
12333333
12333333
checktimeouttask
12333333
12333333
checktimeouttask
123 zs
checktimeouttask
123 zs
其实arr的类型是Array。如果用下面的代码：
val st = SubmitTask("123","lisi")
val hb = HeartBeat(12345)
st match {
case HeartBeat(time) => println(time)
case HeartBeat(time) => println(time)
case SubmitTask(id,name) => println(id + name)
}
则出现编译错误：
Error:(24, 12) constructor cannot be instantiated to expected type;
found : HeartBeat
required: SubmitTask
这里出现错误是因为类型不同，匹配异常。
页:
[1]