fractionDigit

fun Double?.fractionDigit(roundingMode: RoundingMode = RoundingMode.UP): String
fun String?.fractionDigit(roundingMode: RoundingMode = RoundingMode.UP): String
fun BigDecimal.fractionDigit(roundingMode: RoundingMode = RoundingMode.UP): String
fun Long?.fractionDigit(roundingMode: RoundingMode = RoundingMode.UP): String

默认看做 "分" 处理(除以100)