Java getHours(), getMinutes() and getSeconds()

问题:

As I know getHours(), getMinutes() and getSeconds() are all deprecated in Java and they are replaced with Calendar.HOUR_OF_DAY, Calendar.MINUTE, Calendar.SECOND.

These will in fact return the hour, minute and second for that particular moment. However, I would want to retrieved the hours and minutes from a Date variable. For instance,

say the time retrieved from database is

time = Thu Jan 01 09:12:18 CET 1970;

int hours = time.getHours();
int minutes = time.getMinutes();
int seconds = time.getSeconds();

By retrieving the hours, minutes, and seconds, I get

hours = 9
minutes = 12
seconds = 18

So, how do I use Calendar for this function? Although the getHours() has been deprecated but it still worked. I would still like to know if there is an alternative to this.

回答1:

Try this:

Calendar calendar = Calendar.getInstance();
calendar.setTime(yourdate);
int hours = calendar.get(Calendar.HOUR_OF_DAY);
int minutes = calendar.get(Calendar.MINUTE);
int seconds = calendar.get(Calendar.SECOND);

Edit:

hours, minutes, seconds

above will be the hours, minutes and seconds after converting yourdate to System Timezone!

回答2:

Java 8

    System.out.println(LocalDateTime.now().getHour());       // 7
    System.out.println(LocalDateTime.now().getMinute());     // 45
    System.out.println(LocalDateTime.now().getSecond());     // 32

Calendar

System.out.println(Calendar.getInstance().get(Calendar.HOUR_OF_DAY));  // 7 
System.out.println(Calendar.getInstance().get(Calendar.MINUTE));       // 45
System.out.println(Calendar.getInstance().get(Calendar.SECOND));       // 32

Joda Time

    System.out.println(new DateTime().getHourOfDay());      // 7
    System.out.println(new DateTime().getMinuteOfHour());   // 45
    System.out.println(new DateTime().getSecondOfMinute()); // 32

Formatted

Java 8

    // 07:48:55.056
    System.out.println(ZonedDateTime.now().format(DateTimeFormatter.ISO_LOCAL_TIME));
    // 7:48:55
    System.out.println(LocalTime.now().getHour() + ":" + LocalTime.now().getMinute() + ":" + LocalTime.now().getSecond());

    // 07:48:55
    System.out.println(new SimpleDateFormat("HH:mm:ss").format(Calendar.getInstance().getTime()));

    // 074855
    System.out.println(new SimpleDateFormat("HHmmss").format(Calendar.getInstance().getTime()));

    // 07:48:55 
    System.out.println(new Date().toString().substring(11, 20));

回答3:

For a time difference, note that the calendar starts at 01.01.1970, 01:00, not at 00:00. If you're using java.util.Date and java.text.SimpleDateFormat, you will have to compensate for 1 hour:

long start = System.currentTimeMillis();
long end = start + (1*3600 + 23*60 + 45) * 1000 + 678; // 1 h 23 min 45.678 s
Date timeDiff = new Date(end - start - 3600000); // compensate for 1h in millis
SimpleDateFormat timeFormat = new SimpleDateFormat("H:mm:ss.SSS");
System.out.println("Duration: " + timeFormat.format(timeDiff));

This will print:

Duration: 1:23:45.678