Java 如何计算两个日期之间的天数？

我想知道两个日期之间的天数。当我使用下面的代码时，它会引发一个错误。我怎么修理它

import org.joda.time.{DateTime, Days}

val start = "2018-10-01 00:00:00"
val end= "2018-10-12 00:00:00"

val from = DateTime.parse(start)
val to = DateTime.parse(end)

println(from + "<>" + to)

println("Number of days between 2 period: " + Days.daysBetween(from, to).getDays)

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你可以试试这样的

import java.time.LocalDate 
import java.time.format.DateTimeFormatter


val start = "2018-10-01"
val end= "2018-10-12"


val formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd")
val oldDate = LocalDate.parse(start, formatter)

val newDate = LocalDate.parse(end, formatter)
println(newDate.toEpochDay() - oldDate.toEpochDay())

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最后我找到了解决办法：

val format = DateTimeFormat.forPattern("yyyy-MM-dd HH:mm:ss")

val from = format.parseDateTime("2018-10-01 00:00:00")
val to = format.parseDateTime("2018-10-12 00:00:00")

println("Number of days between 2 period: " + Days.daysBetween(from, to).getDays)

乔达，时间已经过时了。使用java.time

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您有解析错误，应该为日期字符串传递正确的DateTimeFormatter。请仔细阅读错误消息。您认为此错误消息是什么意思？可能重复的

val format = DateTimeFormat.forPattern("yyyy-MM-dd HH:mm:ss")

val from = format.parseDateTime("2018-10-01 00:00:00")
val to = format.parseDateTime("2018-10-12 00:00:00")

println("Number of days between 2 period: " + Days.daysBetween(from, to).getDays)

import java.time.LocalDate
import java.time.temporal.ChronoUnit.DAYS

DAYS.between(LocalDate.parse("2018-10-01")
            ,LocalDate.parse("2018-10-12"))  //res0: Long = 11