How to calculate time difference in java?

Question

I want to subtract two timeperiods say 16:00:00 from 19:00:00. Is there any java function for this? The results can be in milliseconds, seconds, or minutes.

Answer 1

    /*
 * Total time calculation.
 */
private void getTotalHours() {
    try {
        // TODO Auto-generated method stub
        if (tfTimeIn.getValue() != null && tfTimeOut.getValue() != null) {
            Long min1 = tfTimeOut.getMinutesValue();
            Long min2 = tfTimeIn.getMinutesValue();
            Long hr1 = tfTimeOut.getHoursValue();
            Long hr2 = tfTimeIn.getHoursValue();
            Long hrsTotal = new Long("0");
            Long minTotal = new Long("0");
            if ((hr2 - hr1) == 1) {
                hrsTotal = (long) 1;
                if (min1 != 0 && min2 == 0) {
                    minTotal = (long) 60 - min1;
                } else if (min1 == 0 && min2 != 0) {
                    minTotal = min2;
                } else if (min1 != 0 && min2 != 0) {
                    minTotal = min2;
                    Long minOne = (long) 60 - min1;
                    Long minTwo = min2;
                    minTotal = minOne + minTwo;
                }
                if (minTotal >= 60) {
                    hrsTotal++;
                    minTotal = minTotal % 60;
                }
            } else if ((hr2 - hr1) > 0) {
                hrsTotal = (hr2 - hr1);
                if (min1 != 0 && min2 == 0) {
                    minTotal = (long) 60 - min1;
                } else if (min1 == 0 && min2 != 0) {
                    minTotal = min2;
                } else if (min1 != 0 && min2 != 0) {
                    minTotal = min2;
                    Long minOne = (long) 60 - min1;
                    Long minTwo = min2;
                    minTotal = minOne + minTwo;
                }
                if (minTotal >= 60) {
                    minTotal = minTotal % 60;
                }
            } else if ((hr2 - hr1) == 0) {
                if (min1 != 0 || min2 != 0) {
                    if (min2 > min1) {
                        hrsTotal = (long) 0;
                        minTotal = min2 - min1;
                    } else {
                        Notification.show("Enter A Valid Time");
                        tfTotalTime.setValue("00.00");
                    }
                }
            } else {
                Notification.show("Enter A Valid Time");
                tfTotalTime.setValue("00.00");
            }
            String hrsTotalString = hrsTotal.toString();
            String minTotalString = minTotal.toString();
            if (hrsTotalString.trim().length() == 1) {
                hrsTotalString = "0" + hrsTotalString;
            }
            if (minTotalString.trim().length() == 1) {
                minTotalString = "0" + minTotalString;
            }
            tfTotalTime.setValue(hrsTotalString + ":" + minTotalString);
        } else {
            tfTotalTime.setValue("00.00");
        }
    }
    catch (Exception e) {
        e.printStackTrace();
    }
}