Question

我想查询SQLite表并获取记录，其中时间字段（以毫秒为单位表示长时间的字符串）在查询时间的明天范围内。

我还有一个字段，它保存记录日期时间如下：

dd / MM / yyyy，HH：mm：ss

您如何推荐实施此功能？

Answer 1

根据您的评论，您可以修改架构以获得更好的性能。因此，最好在数据库中保存时间（unix timestamp）并在其上设置索引。完成后，您可以简单地在当地时区的00:00获取明天的日期，并将其转换为unix时间戳并基于此进行查询。这是你如何在00:00获得明天的时间戳，

public static long getTimeStampAt0000(long timestamp) {
  Calendar givenDate = Calendar.getInstance();
  givenDate.setTimeInMillis(timestamp);
  givenDate.set(Calendar.HOUR_OF_DAY, 0);
  givenDate.set(Calendar.MINUTE, 0);
  givenDate.set(Calendar.SECOND, 0);
  givenDate.set(Calendar.MILLISECOND, 0);
  return givenDate.getTimeInMillis();
}

public static long getTimeStampAt0000ForTomorrow() {
  long now = System.currentTimeMillis();
  long nowAt0000 = getTimeStampAt0000(now);
  if (now == nowAt0000) {
    // if being queried at 00:00, we are assuming we want same or else we can just remove
    // this condition
     return nowAt0000;
  } else {
     return nowAt0000 + 86400000;
  }
}

Answer 2

SQLite doc表示它存储为：

INTEGER as Unix Time，自1970-01-01 00:00:00 UTC以来的秒数。

你某些你有epoch或几秒后的毫秒数吗？

捆绑的java.util.Date和Calendar类非常麻烦。避免他们。在Java 8中使用Joda-Time或新的java.time。*包。

请注意，java.util.Date和Joda-Time DateTime都使用自纪元以来的毫秒数，而新的java.time使用纳秒。根据需要乘以1000L。

在谈论带有日期时间的“今天”和“明天”时，您必须指定一个时区。一天的开始和结束取决于time zone。

// Simulate input.
long millis = DateTime.now().getMillis();

// Use a proper time zone name rather than 3-letter codes.
DateTimeZone timeZone = DateTimeZone.forID( "Asia/Kolkata" ); // Formerly known as Calcutta, India.
DateTime dateTime = new DateTime( millis, timeZone );
DateTime aDayLater = dateTime.plusDays( 1 );

// "Tomorrow" is a span of time.
DateTime startOfToday = new DateTime( timeZone ).withTimeAtStartOfDay();
// Interval comparison is done in "half-open" approach where beginning is inclusive and ending is exclusive.
Interval tomorrow = new Interval( startOfToday.plusDays( 1 ), startOfToday.plusDays( 2 ) );
boolean isDateTimeOccurringTomorrow = tomorrow.contains( dateTime );
boolean isADayLaterOccurringTomorrow = tomorrow.contains( aDayLater );

转储到控制台...

System.out.println( "millis: " + millis );
System.out.println( "dateTime: " + dateTime );
System.out.println( "aDayLater: " + aDayLater );
System.out.println( "startOfToday: " + startOfToday );
System.out.println( "tomorrow: " + tomorrow );
System.out.println( "isDateTimeOccurringTomorrow: " + isDateTimeOccurringTomorrow );
System.out.println( "isADayLaterOccurringTomorrow: " + isADayLaterOccurringTomorrow );

跑步时......

millis: 1392883763016
dateTime: 2014-02-20T13:39:23.016+05:30
aDayLater: 2014-02-21T13:39:23.016+05:30
startOfToday: 2014-02-20T00:00:00.000+05:30
tomorrow: 2014-02-21T00:00:00.000+05:30/2014-02-22T00:00:00.000+05:30
isDateTimeOccurringTomorrow: false
isADayLaterOccurringTomorrow: true

检查明天是否有毫秒的时间

2 个答案: