示例运行于 2020 年 4 月 25 日

DateTimeFormatter 时间转换

localDate to String

val date = LocalDate.now()
val fmt = DateTimeFormatter.ofPattern("yyyy-MM-dd")
val dateStr = date.format(fmt)
println(dateStr)  // 2020-04-25

String to LocalDate

val str = "2019-01-01"
val fmt = DateTimeFormatter.ofPattern("yyyy-MM-dd")
val parsedDate = LocalDate.parse(str, fmt) 
println(parsedDate) // 1546300800

时间比较

isBefore, isAfter, isEqual

获取系统当前日期，和某个时间【字符串】

val date = LocalDate.now()
val fmt = DateTimeFormatter.ofPattern("yyyy-MM-dd")
val str0424 = "2019-04-24"
val parsedDate0424 = LocalDate.parse(str0424, fmt)
val result = date.isAfter(parsedDate0424)
println(result) // true

>,<,= 比较

val date = LocalDate.now()
val fmt = DateTimeFormatter.ofPattern("yyyy-MM-dd")
val str0424 = "2019-04-24"
val parsedDate0424 = LocalDate.parse(str0424, fmt)
val result = date.isAfter(parsedDate0424)
println(date < parsedDate0424) // false
println(date == parsedDate0424) // false
println(date > parsedDate0424) // true

文档参考

https://docs.oracle.com/javase/8/docs/api/java/time/format/DateTimeFormatter.html