Fetch Epoch time

Question

Hi: I want to build a small java code that returns the unix epoch time for 12:00AM yesterday and 11:59PM yesterday. Anybody have code which does the above that you can share ?
TIA
Ravi

Answer 1

This should do what you're looking for:
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
public class Main {
  public Main() {
  public static void main(String[] args) {
    final long MS_PER_DAY = 24 * 60 * 60 * 1000;
    // Get the current time
    Date now = new Date();
    // Get a time from yesterday
    Date yesterday = new Date(now.getTime() - MS_PER_DAY);
    Calendar calendar = new GregorianCalendar();
    calendar.setTime(yesterday);
    // Get the time yesterday morning at 12:00AM
    calendar.set(Calendar.HOUR_OF_DAY, 0);
    calendar.set(Calendar.MINUTE, 0);
    calendar.set(Calendar.SECOND, 0);
    Date yesterdayStart = calendar.getTime();
    // Get the time yesterday night at 11:59:59PM
    calendar.set(Calendar.HOUR_OF_DAY, 23);
    calendar.set(Calendar.MINUTE, 59);
    calendar.set(Calendar.SECOND, 59);
    Date yesterdayEnd = calendar.getTime();
    System.out.println(
      "Yesterday start: " + yesterdayStart +
      "\t Since Epoch:" + yesterdayStart.getTime());
    System.out.println(
      "Yesterday end:   " + yesterdayEnd +
      "\t Since Epoch:" + yesterdayEnd.getTime());
}If you want to be slightly more efficient, you could take the "yesterdayStart.getTime()" and add (MS_PER_DAY - 1000) to get the yesterdayEndTime (or, even better, use -1 instead of -1000 if you want to get all the way to 11:59:59:999).