I have two strings which are used to store time in the format hh:mm.I want to the compare these two to know which time is greater.Which is the easiest way to go about this?
Use the SimpleDateFormat and Date classes. The latter implements Comparable, so you should be able to use the .compareTo() method to do the actual comparison. Example:
String pattern = "HH:mm";
SimpleDateFormat sdf = new SimpleDateFormat(pattern);
try {
Date date1 = sdf.parse("19:28");
Date date2 = sdf.parse("21:13");
// Outputs -1 as date1 is before date2
System.out.println(date1.compareTo(date2));
// Outputs 1 as date1 is after date1
System.out.println(date2.compareTo(date1));
date2 = sdf.parse("19:28");
// Outputs 0 as the dates are now equal
System.out.println(date1.compareTo(date2));
} catch (ParseException e){
// Exception handling goes here
}
See the SimpleDateFormat documentation for patterns.
Well, if they're actually hh:mm (including leading zeroes, and in 24-hour format) then you can just compare them lexicographically (i.e. using String.compareTo(String)). That's the benefit of a sortable format :)
Of course, that won't check that both values are valid times. If you need to do that, you should probably parse both times: check the length, check the colon, parse two substrings, and probably multiply the number of hours by 60 and add it to the number of minutes to get a total number of minutes. Then you can compare those two totals.
EDIT: As mentioned in the comments, if you do need to parse the values for whatever reason, personally I would recommend using Joda Time (possibly a cut down version, given the mobile nature) rather than SimpleDateTimeFormat and Date. Joda Time is a much nicer date and time API than the built-in one.
I have written functions for this before in my Android program and I will gladly share the source below.
Functions (will explain later using "how to use" code):
public static void String setFormattedTimeString(final String formatExpr,
final long timeStampInSeconds) {
final Date dateFromTimeStamp = new Date(timeStampInSeconds);
final SimpleDateFormat simpleformat = new SimpleDateFormat(formatExpr);
final String formattedDateInString = simpleformat.format(dateFromTimeStamp);
return formattedDateInString;
}
public static void Calendar setCalendar(final int year, final int month,
final int day) {
final Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.DAY_OF_MONTH, day);
calendar.set(Calendar.MONTH, month);
calendar.set(Calendar.YEAR, year);
return calendar;
}
public static void double timeDifferenceInDays(final Calendar firstDate,
final Calendar secondDate) {
final long firstDateMilli = firstDate.getTimeInMillis();
final long secondDateMilli = secondDate.getTimeInMillis();
final long diff = firstDateMilli - secondDateMilli;
// 24 * 60 * 60 * 1000 because I want the difference in days. Change
// as your wish.
final double diffDays = (double) diff / (double) (24 * 60 * 60 * 1000);
return diffDays;
}
And this is how I use them to calculate difference (days in this example). In this example I'm assuming you have a timestamp to use, otherwise you can change easily:
// Here you maybe have a timestamp in seconds or something..
// This is ONE Calendar.
final String yearString = MyToolClass.setFormattedTimeString("y", timestamp);
final int year = Integer.parseInt(yearString);
final String monthString = MyToolClass.setFormattedTimeString("M", timestamp);
final int month = Integer.parseInt(monthString);
final String day_in_monthString = MyToolClass.setFormattedTimeString("d",
timestamp);
final int day_of_month = Integer.parseInt(day_in_monthString);
final Calendar calendarOne = MyToolClass.setCalendar(year, month,
day_of_month);
// Same stuff for Calendar two.
// Calculate difference in days.
final double differenceInDays = MyToolClass.timeDifferenceInDays(calendarOne,
calendarTwo);
Related
This question already has answers here:
Calculating days between two dates with Java
(16 answers)
Closed 5 years ago.
I've got a list of dates in format "yyyy-MM-dd", I'd like to have a number of days between my today date "2017-04-15" and first date from list which is higher than mine today date.
I am assuming that your events are not sorted by date. I am assuming that you can use Java 8. This is one of the tasks that have become so much easier with the java.time classes introduced in Java 8 (and backported to Java 6 and 7).
Use LocalDate.now() to get today’s date.
Iterate through your events, all the time keeping track of the closest future event date. For each event use LocalDate.parse() to convert the event’s date to a LocalDate. The 1-arg parse method fits your format. Compare with today’s date and with the earliest future event date encountered so far; if between, store as the new closest date. Use isAfter() and/or isBefore for the comparisons.
After your loop, you will either know the date or you will know that there are no future events at all. In the former case, use ChronoUnit.DAYS.between() to get the number of days from the current date to the event date.
Solution 1
If you are using joda library, then it will be easy, you can use Days.daysBetween :
Date startDate = ...;
Date endDate = ...;
int nbrDays = Days.daysBetween(new LocalDate(startDate), new LocalDate(endDate)).getDays();
Solution 2
Date startDate = ...;
Date endDate = ...;
Calendar cal = Calendar.getInstance();
cal.setTime(startDate);
int day1 = cal.get(Calendar.DAY_OF_MONTH);
cal.setTime(endDate);
int day2 = cal.get(Calendar.DAY_OF_MONTH);
int nbrDays = day1 - day2;
System.out.println(nbrDays);
You have to import :
import java.util.Calendar;
import java.util.Date;
Solution 3
If your dates are in this format "yyyy-MM-dd" so you can have two dates like this :
String date1 = "1991-07-03";
String date2 = "2017-04-15";
What you should to do, split your dates with - :
String spl1[] = date1.split("-");
String spl2[] = date2.split("-");
Calculate the difference between the two dates :
int year1 = Integer.parseInt(spl1[0]);
int month1 = Integer.parseInt(spl1[1]);
int days1 = Integer.parseInt(spl1[2]);
int year2 = Integer.parseInt(spl2[0]);
int month2 = Integer.parseInt(spl2[1]);
int days2 = Integer.parseInt(spl2[2]);
//make some calculation and in the end you can get the diffidence, this work i will let it for you.
This should solve your problem.
SimpleDateFormat myDateFormat = new SimpleDateFormat("yyyy-MM-dd");
List<Date> dateList = new ArrayList<Date>();
try {
beforeDate = myDateFormat.parse("2016-01-13");
dateList.add(myDateFormat.parse("2016-01-10"));
dateList.add(myDateFormat.parse("2016-01-11"));
dateList.add(myDateFormat.parse("2016-01-12"));
dateList.add(myDateFormat.parse("2016-01-19"));
dateList.add(myDateFormat.parse("2016-01-20"));
dateList.add(myDateFormat.parse("2016-01-21"));
} catch (ParseException e) {
System.out.println(e.getMessage());
}
//add here
boolean check = true;
for(int i = 0; check && i < dateList.size();i++){
if(dateList.get(i).after(beforeDate)){
afterDate = dateList.get(i);
check = false;
}
}
System.out.println(beforeDate+" "+afterDate);
long days = ChronoUnit.DAYS.between(LocalDate.parse(myDateFormat.format(beforeDate)), LocalDate.parse(myDateFormat.format(afterDate)));
if(days>0){
System.out.println(days);
}else{
System.out.println(0-days);
}
if you want to sort dateList then want to get afterDate then use this code after addition of date elements in dateList
Collections.sort(dateList,new Comparator<Date>() {
#Override
public int compare(Date o1, Date o2) {
return o1.compareTo(o2);
}
});
This will allow you to sort dates in ascending order..
I need to compare 2 dates to a third date and ignore the time portion of all of them.
The code below generates a parse exception because the toString() method returns something like "Wed Feb 26 00:00:00 EST 2014".
Any suggestions on how I might fix this?
private boolean needToSendEmail(EmSelfCertEntity escd) throws ParseException {
boolean sendEmail = false;
DateFormat df = new SimpleDateFormat("MM/dd/yyyy");
Date justTheDate = df.parse(escd.getCurrentFCESDate().toString());
Calendar firstSent = Calendar.getInstance();
firstSent.setTime(justTheDate);
justTheDate = df.parse(new Date().toString());
Calendar firstFollowUp = Calendar.getInstance();
firstFollowUp.setTime(justTheDate);
firstFollowUp.add(Calendar.DATE, -daysToFirstFollowUpEmail);
Calendar secondFollowUp = Calendar.getInstance();
secondFollowUp.setTime(justTheDate);
secondFollowUp.add(Calendar.DATE, -daysToSecondFollowUpEmail);
if ((firstSent.before(firstFollowUp) && escd.countEmailsSent <= 1)
|| (firstSent.before(secondFollowUp) && escd.countEmailsSent <= 2)) {
sendEmail = true;
}
return sendEmail;
}
Thanks!
Why are you parsing the String when you already have the Date?
If you want to format your existing Date into the format you specified, use the format() method instead:
String justTheDate = df.format(new Date());
Then you can compare the Strings using the equals() method to check for matches.
Edit- By the way, if Java 8 is an option (it came out on Tuesday!), its new DateTime features will do exactly what you're looking for: http://docs.oracle.com/javase/tutorial/datetime/
The cause for your exception is that toString in escd.getCurrentFCESDate().toString()
delivers another format than "MM/dd/yyyy".
So make sure that either your format String in line SimpleDateFormat("MM/dd/yyyy") is correct.
Or check if you can get the year, month, and day directly from getCurrentFCESDate().
Just Use the calendar to create a date, where you take the year, months, day from the existing date but set the hours, minutes, seconds and millis to zero.
The result will be a Date object:
Something like
firstSent.set(Calendar.HOUR, 0);
firstSent.set(Calendar.MINUTE, 0);
firstSent.set(Calendar.SECOND, 0);
firstSent.set(Calendar.MILLISECOND, 0);
Then use before() and after()
The easiest approach would be to convert the dates to numbers in this format: yyyyMMdd.
And after that you can just compare the numbers.
But yes, please work with timezone adjustments before converting to numbers.
you can calculate the time in millis and substract the time with a simple / division.
This way you can compare 2 longs and check if one is bigger than another.
Take this example where we get to different dates for today (500 milliseconds from one to another) but... if you divide by 86400000 then... you get the same number.
Try this:
public static void main(String[] args) throws Exception {
Date d1= new Date();
Thread.sleep(500);
Date d2= new Date();
final int MILLISECONDS = 1000;
final int SECONDS = 60;
final int MINUTES = 60;
final int HOURS = 24;
final long MILLI_PER_DAY= MILLISECONDS*SECONDS*MINUTES*HOURS;
System.out.println(MILLI_PER_DAY);
System.out.println(d1.getTime());
System.out.println(d2.getTime());
System.out.println(d1.getTime()/MILLI_PER_DAY);
System.out.println(d2.getTime()/MILLI_PER_DAY);
}
You will see that the last 2 entries are the same:
1395338535623 --> time 1 in millis
1395338536123 --> time 2 in millis
16149 --> time 1 / 86400000
16149 --> time 2 / 86400000 --> THE SAME
I need help to check following conditions related to date and time...
Calendar cal = Calendar.getInstance();
SimpleDateFormat dateFormat = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss");
String CurrentDate= dateFormat.format(cal.getTime());
String ModifiedDate = dateTime taken from date n time picker widget ;
i have to check :
current ModifiedDate is not less than 5 minutes of current time
How to check this conditon in Android / Java..........?
Why are you formatting the date?
It's much easier to work with data in a "natural" representation rather than in a string representation. It's not clear whether your modified date has to be taken as a string, but if it does, the first thing you should do is parse it. You can then compare that with the current date and time using:
// Check if the value is later than "now"
if (date.getTime() > System.currentTimeMillis())
or
// Check if the value is later than "now + 5 minutes"
if (date.getTime() > System.currentTimeMillis() + TimeUnit.MINUTES.toMillis(5))
It's not really clear what you mean by "current ModifiedDate is not less than 5 minutes of current time" - whether you mean that it's not less than 5 minutes after, or not less than 5 minutes earlier, or something like that - but you should be able to change the code above to handle your requirements.
If you do a lot of date/time manipulation, I'd strongly recommend the use of Joda Time, which is a much better date/time API than java.util.Date/Calendar.
To check whether the given time is before/after the current time ,
There is a Calendar instance in Android...to compare date time values.
Calendar current_time = Calendar.getInstance ();
current_time.add(Calendar.DAY_OF_YEAR, 0);
current_time.set(Calendar.HOUR_OF_DAY, hrs);
current_time.set(Calendar.MINUTE, mins );
current_time.set(Calendar.SECOND, 0);
Calendar given_time = Calendar.getInstance ();
given_time.add(Calendar.DAY_OF_YEAR, 0);
given_time.set(Calendar.HOUR_OF_DAY, hrs);
given_time.set(Calendar.MINUTE, mins );
given_time.set(Calendar.SECOND, 0);
current_time.getTime();
given_time.getTime();
boolean v = current_calendar.after(given_calendar);
// it will return true if current time is after given time
if(v){
return true;
}
public static boolean getTimeDiff(Date dateOne, Date dateTwo) {
long timeDiff = Math.abs(dateOne.getTime() - dateTwo.getTime());
int day = (int) TimeUnit.MILLISECONDS.toHours(timeDiff);
int min= (int) ( TimeUnit.MILLISECONDS.toMinutes(timeDiff) - TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS.toHours(timeDiff)));
if(day>1)
{
return false;
}
else if(min>5)
{
return false;
}
else
{
return true;
}
}
usage:
System.out.println(getTimeDiff(new Date("01/13/2012 12:05:00"),new Date("01/12/2012 13:00:00")));
Please help me to write a method that returns number (int) of days from a provided day to the todays date.
So let's say, I am providing into a method an int 110515 (for May 15, 2011). It should return 9 (inclusive or exclusive is not important to me).
If you can use Joda, this is super simple:
Days d = Days.daysBetween(startDate, endDate);
int days = d.getDays();
Of course you could combine these.
int days = Days.daysBetween(startDate, endDate).getDays();
Joda objects can go back and forth between the JDK's date class pretty easily.
For the first part, make a DateFormatter then parse the string based on it, like this:
DateTimeFormatter fmt = DateTimeFormat.forPattern("yyyyMMdd");
DateTime dt = fmt.parseDateTime(strInputDateTime);
(After turning the int into a string of course.)
Should dates in the future include the current day? Meaning if today is May 24th 2011, should 110529 result in 4 or 5?
public static long numberOfDays(final long date) throws ParseException {
final Calendar compare = Calendar.getInstance();
compare.setTime(new SimpleDateFormat("yyMMdd").parse(String.valueOf(date)));
final int dstOffset = compare.get(Calendar.DST_OFFSET);
final long currentTimeMillis = System.currentTimeMillis();
final long compareTimeInMillis = compare.getTimeInMillis();
long difference = 0;
if (currentTimeMillis >= compareTimeInMillis) {
difference = currentTimeMillis - compareTimeInMillis - dstOffset;
} else {
difference = compareTimeInMillis - currentTimeMillis + dstOffset;
}
return difference / (24 * 60 * 60 * 1000);
}
Since this seems like a homework question I will help you out. You will want to use Calendar.getTimeInMillis. Then you will want to create a constant that is NUMBER_OF_MILLIS_IN_DAY . From there you subtract the initialDate from the currentDate (both time in millis) and divide by the constant.
I am doing some table testing in word, all of the JUnits are done but i am having trouble testing a method - as i am the tester in this project and not the coder i am struggling to understand what is actually correct or not
public GregorianCalendar calcDeparture(String date, String time) {
String[] calDate = new String[3];
String[] calTime = new String[2];
calDate[0] = (date.substring(0, 2)); //Dat
calDate[1] = date.substring(2, 5); //Month
calDate[2] = "20" + date.substring(5, 7); //Year
calTime = time.split(":");
//Adds the year, month and day and hour and minute from the above splited arrays
int year = Integer.parseInt(calDate[2]);
int month = monthToInt(calDate[1]);
int day = Integer.parseInt(calDate[0]);
int hour = Integer.parseInt(calTime[0]);
int minute = Integer.parseInt(calTime[1]);
GregorianCalendar newDeparture = new GregorianCalendar(year, month, day, hour, minute, 0);
return newDeparture;
}
This is the method I am testing. If i pass it the values of "01AUG07 "14:40" i get a gregorian calander back but i don't know if the values inside of it are correct so i can't tick the passed or failed box. What i get back in the BlueJ object inspector is a load of really long numbers :D
can i get some help please
thanks
I suggest to check all the relevant values of the calendar at the same time using a SimpleDateFormat() like so:
SimpleDateFormat f = new SimpleDateFormat ("yyyy-MM-dd HH:mm");
String s = f.format (calcDeparture(yourDate, yourTime));
assertEquals ("2007-08-01 14:40", s);
Now call your method with odd dates (like 31.12.2999, August 45th, February 29th 2001, etc) to see what you get and how you should handle errors.
BlueJ? Consider using an IDE, not an educational software
The method is terribly written - working with dates using a strictly-formatted String is wrong.
Calendar (which is the supertype of GregorianCalendar) has the get method, which you can use like:
Calendar calendar = calcDeparture(yourDate, yourTime);
int day = calendar.get(Calendar.DAY_OF_YEAR);
int moth = calendar.get(Calendar.MONTH); //this is 0 based;
and so on
Why can you just not use the standard getters to check the individual fields, along the lines of:
Calendar cal = calcDeparture("01AUG07", "14:40");
if (cal.get(Calendar.YEAR) != 2007) { ... }