Java LocalDateTiem取得系統所在時區當天及昨天午夜（00:00）的毫秒。
方法一，取得當日期昨天的LocalDate後將時間設為00:00。
import java.time.LocalDate;
import java.time.ZoneId;
public class Main {
public static void main(String[] args) {
// 本篇撰寫於Taiwan 2020-05-23 （時區為"Asia/Taipei"）
long todayMidnightMillis = getTodayMidnightMillis();
long yesterdayMidnightMillis = getYesterdayMidnightMillis();
System.out.println(todayMidnightMillis); // 1590163200000 (Sat May 23 2020 00:00:00) 本日00:00
System.out.println(yesterdayMidnightMillis); // 1590076800000 (Fri May 22 2020 00:00:00) 昨日00:00
}
private static long getTodayMidnightMillis() {
LocalDate d = LocalDate.now();
return toMidnightMillis(d);
}
private static long getYesterdayMidnightMillis() {
LocalDate d = LocalDate.now().minusDays(1L);
return toMidnightMillis(d);
}
private static long toMidnightMillis(LocalDate d) {
return d.atTime(
0, // hour
0, // minute
0 // second
).atZone(ZoneId.systemDefault()).toInstant().toEpochMilli();
}
}
方法二，取得當日及昨日的LocalDatTime後將時間部分改為00:00。
package com.abc.demo;
import java.time.LocalDateTime;
import java.time.ZoneId;
public class Main {
public static void main(String[] args) {
// 本篇撰寫於Taiwan 2020-05-21 （時區為"Asia/Taipei"）
long todayMidnightMillis = getTodayMidnightMillis();
long yesterdayMidnightMillis = getYesterdayMidnightMillis();
System.out.println(todayMidnightMillis); // 1589990400000 (Thu May 21 2020 00:00:00) 本日00:00
System.out.println(yesterdayMidnightMillis); // 1589904000000 (Wed May 20 2020 00:00:00) 昨日00:00
}
private static long getTodayMidnightMillis() {
LocalDateTime d = LocalDateTime.now();
return toMidnightMillis(d);
}
private static long getYesterdayMidnightMillis() {
LocalDateTime d = LocalDateTime.now().minusDays(1L);
return toMidnightMillis(d);
}
private static long toMidnightMillis(LocalDateTime d) {
return LocalDateTime.of(
d.getYear(),
d.getMonthValue(),
d.getDayOfMonth(),
0, // hour
0, // minute
0 // second
).atZone(ZoneId.systemDefault()).toInstant().toEpochMilli();
}
}
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