Kotlin学习笔记（三）异常

案例1

fun test(num: Int) {
    val percentage = if (num in 0..100) {
        num
    } else {
        throw IllegalArgumentException("A percentage value must be between 0 and 100: $num")
    }
}

案例2

fun readNumber(reader: BufferedReader): Int? {
    try {
        val line = reader.readLine()
        return Integer.parseInt(line)
    } catch (e: NumberFormatException) {
        return null;
    } finally {
        reader.close()
    }
}

fun main(args: Array<String>) {
    val reader = BufferedReader(StringReader("239"))
    println(readNumber(reader))
}