I have a little problem with the translation of this data 19/12/2005
17:30:45 to mileseconds. I don't know why, I am getting a wrong translation to Jun 28 17:30:45 CEST 1995 Time :804353445798
The code I used is this :
private static long ConvertTimeToTimeStamp(String time) {
Integer[] data = new Integer[6];
String [] tokens = time.split(" ");
System.out.println(tokens[0]);
System.out.println(tokens[1]);
String[] d_m_y = tokens[0].split("/");
String[] hh_mm_ss = tokens[1].split(":");
for (int i = 0; i < d_m_y.length; i++) {
data[i]=Integer.parseInt(d_m_y[i]);
// System.out.println(d_m_y[i]);
}
for (int i = 0; i < hh_mm_ss.length; i++) {
data[i+3]=Integer.parseInt(hh_mm_ss[i]);
// System.out.println(hh_mm_ss[i]);
}
//Calendar calendar = Calendar.getInstance();
GregorianCalendar calendar = new GregorianCalendar();
calendar.set(data[0]+1970, data[1], data[2], data[3],data[4],data[5]);
System.out.println(calendar.getTime().toString());
return calendar.getTimeInMillis();
}
You should not parse the date manually - use a date format instead:
String s = "19/12/2005 17:30:45";
Date d = new SimpleDateFormat("dd/MM/yyyy HH:mm:ss").parse(s);
Treat this object from the outset as a date. That will be much more reliable.
Use SimpleDateFormat.parse() to parse your string into a date/time. Otherwise you're reduced to string parsing/splitting/recombining etc with no bounds-checking, type-checking etc. Your solution is stringly-typed, not strongly-typed.
I've referenced the standard Java libraries, but Joda-Time is a better bet for doing date work in Java and I would advise adopting this for a more intuitive and safer API.
Forget about it. Use a SimpleDataFormat object with pattern dd/MM/yyyy HH:mm:ss to parse() the String into a date object.
try...
private static long ConvertTimeToTimeStamp(String time) {
//19/12/2005 17:30:45
SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy hh:mm:ss");
java.util.Date d = sdf.parse(time);
return d.getTime();
}
You are mixing the order of year, month and day. The set method is expecting them in the following order: year, month, day and you are providing them as day + 1970, month, year.
Having said that, you might actually be much more happy with a library like joda-time.
Related
I have two strings which can be seen as time stamps:
String min="2017-04-15 13:27:31";
String max="2017-04-15 13:40:01";
Assume we want to find out the time passed from first time stamp to the second one. If there was only the time and no date included, I could get it using my following code:
String[] partsMin=min.split(":");
String[] partMax=max.split(":");
int diffZero=Integer.parseInt(partMax[0])-Integer.parseInt(partsMin[0]);
int diffOne=Integer.parseInt(partMax[1])-Integer.parseInt(partsMin[1]);
int diffOTwo=Integer.parseInt(partMax[2])-Integer.parseInt(partsMin[2]);
diffInSec=diffZero*3600+diffOne*60+diffOTwo;
So here is the question. How to get the job done while there is a date within the time stamp?
I would construct LocalDateTime instances from it.
Then i would get the milliseconds from it and substract startTime from EndTime.
What is remaining are the milliseconds passed between the two. A DateTimeFormatter is helpful as well for this purpose.
String strMin = "2017-04-15 13:27:31";
DateTimeFormatter formatterTime = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
LocalDateTime dateTimeMin = LocalDateTime.parse(strMin, formatter);
String strMax = "2017-04-15 13:40:01";
LocalDateTime dateTimeMax = LocalDateTime.parse(strMax, formatter);
long minutes = ChronoUnit.MINUTES.between(dateMin, dateMaxto);
long hours = ChronoUnit.HOURS.between(dateMin, dateMax);
If you want to get the milliseconds:
long millisPassed = dateMax.toEpochMilli() - dateMax.toEpochMilli();
Use the java date time libraries (even the old Date class would be fine for this) to parse the string into a proper object.
Depending on the date time library you chose you can then look at the difference between them. The simplest would be something like:
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
Date date1 = sdf.parse(str1);
Date date2 = sdf.parse(str2);
long differenceInSeconds = (date2.getTime()-date1.getTime())/1000;
The new Java 8 time classes would also allow you to do this and would be better to learn going forwards. I can't remember the syntax for that off the top of my head though.
Did you try with replace all the other part of your String like this :
String[] partsMin = min.replaceAll("\\d+-\\d+-\\d+", "").trim().split(":");
String[] partMax = max.replaceAll("\\d+-\\d+-\\d+", "").trim().split(":");
Doing this in your code:
int diffZero=Integer.parseInt(partMax[0])
is the same as doing:
int diffZero=Integer.parseInt("2017-04-15")
that is generating an Exception(NumberFormatException)
you should better try to PARSE those strings min and max into a date
Edit:
you can inspect your code/ variables: and see that splitting to ":" is not giving you back the correct array since the element at index 0 is holding more information than you need...
but as I said before, you are going on the wrong path, dont re invent the wheel and look how practical will get using the APIs that java has for us:
String min = "2017-04-15 13:27:31";
String max = "2017-04-15 13:40:01";
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
LocalDateTime dateTimeMin = LocalDateTime.parse(min, formatter);
LocalDateTime dateTimeMax = LocalDateTime.parse(max, formatter);
long days = ChronoUnit.DAYS.between(dateTimeMin, dateTimeMax);
long minutes = ChronoUnit.MINUTES.between(dateTimeMin, dateTimeMax);
System.out.println(days);
System.out.println(minutes);
use SimpleDateFormat to parse the date string, and do operation on Date result, you will get right value. This works well for date between '2017-02-28 23:59:59' and '2017-03-01 00:00:01'
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
Date date1 = format.parse("2017-02-28 23:59:59");
Date date2 = format.parse("2017-03-01 00:00:01");
long time1 = date1.getTime();
long time2 = date2.getTime();
long diff = time2 - time2; // should be 2000
This question already has answers here:
how to get a list of dates between two dates in java
(23 answers)
Closed 6 years ago.
I'm trying to get an array of Dates, while my input is a 'from'/'to' structure.
So my input is:
String date1 = "2014-01-01";
String date2 = "2014-05-01";
My output should be an Arraylist with all dates between date1 and date2.
I've already looked for this, but I could only find questions about the difference between 2 dates:
SimpleDateFormat myFormat = new SimpleDateFormat("dd MM yyyy");
String inputString1 = "23 01 1997";
String inputString2 = "27 04 1997";
try {
Date date1 = myFormat.parse(inputString1);
Date date2 = myFormat.parse(inputString2);
long diff = date2.getTime() - date1.getTime();
System.out.println ("Days: " + TimeUnit.DAYS.convert(diff,TimeUnit.MILLISECONDS));
} catch (ParseException e) {
e.printStackTrace();
}
Any hints or suggestions? All other questions are for iOS or SQL.
Take a look at JodaTime: http://joda-time.sourceforge.net/apidocs/org/joda/time/DateTime.html
DateTime dateTime1 = new DateTime(date1);
DateTime dateTime2 = new DateTime(date2);
List<Date> allDates = new ArrayList();
while( dateTime1.before(dateTime2) ){
allDates.add( dateTime1.toDate() );
dateTime1 = dateTime1.plusDays(1);
}
Below is the code to get array of dates between the two string date.
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.List;
public class DateFormatExample {
public static void main(String[] args) {
// TODO Auto-generated method stub
SimpleDateFormat myFormat = new SimpleDateFormat("yyyy-MM-dd");
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
String date1 = "2014-01-01";
String date2 = "2014-05-01";
try {
Date d1 = myFormat.parse(date1);
Date d2 = myFormat.parse(date2);
List<Date> allDates = new ArrayList<Date>();
List<String> allDatesString = new ArrayList<String>();
while( d1.before(d2) ){
d1 = addDays(d1, 1);
allDates.add(d1);
allDatesString.add(formatter.format(d1));
}
System.out.println(allDates);
System.out.println(allDatesString);
} catch (ParseException e) {
e.printStackTrace();
}
}
private static Date addDays(Date d1, int i) {
GregorianCalendar cal = new GregorianCalendar();
cal.setTime(d1);
cal.add(Calendar.DATE, 1);
return cal.getTime();
}
}
If you don't want to use third party libraries you can use Calendar:
Check here a working demo.
public static void main(String[] args) throws Exception {
SimpleDateFormat myFormat = new SimpleDateFormat("dd MM yyyy");
String inputString1 = "23 01 1997";
String inputString2 = "27 04 1997";
ArrayList<Date> dates = new ArrayList<Date>();
try {
Date date1 = myFormat.parse(inputString1);
Calendar c1 = DateToCalendar(date1);
Date date2 = myFormat.parse(inputString2);
Calendar c2 = DateToCalendar(date2);
while (!areEqualDate(c1, c2)) {
dates.add(c1.getTime());
System.out.println (c1.getTime());
c1.add(Calendar.DAY_OF_YEAR, 1);
}
} catch (ParseException e) {
e.printStackTrace();
}
// ArrayList<Date> dates >> contain all dates between both given days.
}
private static boolean areEqualDate(Calendar c1, Calendar c2) {
if (c1.get(Calendar.YEAR) != c2.get(Calendar.YEAR)) return false;
if (c1.get(Calendar.MONTH) != c2.get(Calendar.MONTH)) return false;
if (c1.get(Calendar.DAY_OF_YEAR) != c2.get(Calendar.DAY_OF_YEAR)) return false;
return true;
}
public static Calendar DateToCalendar(Date date) {
Calendar cal = Calendar.getInstance();
cal.setTime(date);
return cal;
}
I like JodaTime, but this can also be done without 3rd party libraries by using java.util.Calendar. Given a Calendar object, one can use its add method to increase certain fields of the date while honoring the calendar rules (like adding 1 day to the 31st of January gets you to the 1st of February, not to the 32nd of January).
First get the dates into one Calendar object each, in the correct chronological order so adding is going in the right direction later:
Calendar cStart = Calendar.getInstance(),
cStop = Calendar.getInstance();
if (date1.before(date2)) {
cStart.setTime(date1);
cStop.setTime(date2);
} else {
cStart.setTime(date2);
cStop.setTime(date1);
date1 and date2 are the parsed Date objects from your question, for simplicity's sake.
Next, loop over an "add 1 to day-of-year" instruction until this gets you beyond the stop date:
do {
System.out.println(pretty(cStart));
cStart.add(Calendar.DAY_OF_YEAR, 1);
} while (cStart.before(cStop));
And lastly print the stop date
System.out.println(pretty(cStop));
pretty() is just some mini method sending the calendar through a SDF, like the one you used for parsing the Strings in the first place.
This solution will print the date range, including the start and stop dates, and might need some tweaking around the edge cases (like date1==date2). Can be easily adapted to exclude the start and stop dates. Printing can be swapped for aggregation of course. To get a Date object from the calendar, use the getTime() method (returns a snapshot, not a live reference).
The documentation for the relevant (Gregorian)Calendar can be found here.
In case you are using Guava, there is a very elegant solution to this problem.
Guava has two neat classes, such as Range and ContiguousSet, which implement exactly what you need: first one operates on ranges of values, and second one - is able to convert a range to a set of discrete values.
Example of usage of both (together with JodaTime):
LocalDate start = LocalDate.parse("2015-01-01");
LocalDate end = LocalDate.parse("2019-02-01");
Range<LocalDate> range = Range.closed(start, end); //Creates a "closed" range, that is both dates are inclusive. There are also options like "openClosed", "closedOpen" and "open"
final Set<LocalDate> daySet = ContiguousSet.create(range, LocalDateDomain.INSTANCE); //Create a "virtual" set of days in given the range. "virtual" part means that if you create a set of 10 thousand years, it will not eat your memory at all
for (LocalDate day : daySet) {
//...operation...
}
Personally, I really prefer this way, as it eliminates some problems with understanding closed/open ranges, and makes code much easier to read and understand, while making no impact on performance. Also, it works with any kinds of dates, any libraries (you can swap YodaTime to Java8 Dates or even Java7- Date-based implementation).
Moreover, it allows you to do some neat operations on ranges like intersections, unions, spanning of ranges, incredibly fast "contains" and so on.
Only downsides are:
Dependence on Guava.
Need to create a special "DiscreteDomain" class, which Guava uses to understand where one date ends and other begins.
Example of LocalDateDomain implementation which operates as a bridge between Guava and JodaTime:
public class LocalDateDomain extends DiscreteDomain<LocalDate> {
public static final LocalDateDomain INSTANCE = new LocalDateDomain();
#Override
public LocalDate next(LocalDate value) {
return value.plusDays(1);
}
#Override
public LocalDate previous(LocalDate value) {
return value.minusDays(1);
}
#Override
public long distance(LocalDate start, LocalDate end) {
return Days.daysBetween(start, end).getDays();
}
}
I already know that OP isn't using Java 8 but here's the current solution - Java has been revamped and the new java.time API does every conceivable job in that regard:
//change these values :
LocalDate ld1 = LocalDate.ofEpochDay(0);
LocalDate ld2 = LocalDate.now();
//do NOT change these:
final LocalDate begin = ld1.isBefore(ld2) ? ld1 : ld2;
final LocalDate end = ld2.isAfter(ld1) ? ld2 : ld1;
for (int i = 0; i < begin.until(end, ChronoUnit.DAYS); i++) {
final LocalDate curDate = begin.plusDays(i);
System.out.println("current date : " + curDate);
}
This will output every valid day between the two dates whereas most of the other solutions will also give you invalid ones; heres the thing: temporal calculations need to be done on timezone-independent data - the output on the other hand may very well be timezone and/or chronology -dependent.
Thats why there are packages like java.time.format - simply calculate your time/date values and format them for your chosen region ... thats how its done correctly.
If you need to convert temporal input there are also useful functions in the time-API, i recommend doing a thorough tutorial on the subject, a few good introductions may be this and especially that :
There are two basic ways to represent time. One way represents time in
human terms, referred to as human time, such as year, month, day,
hour, minute and second. The other way, machine time, measures time
continuously along a timeline from an origin, called the epoch, in
nanosecond resolution. The Date-Time package provides a rich array of
classes for representing date and time. Some classes in the Date-Time
API are intended to represent machine time, and others are more suited
to representing human time.
I am traversing an arraylist and want to format all the timestamps i get from response but i observed that it takes around 3 seconds to convert 12600 records using DateFormat method and if i use SimpleDateFormat it takes 2 seconds.Strange!!
But I want to decrease this conversion time.
ArrayList<String> timestampsList = new ArrayList<String>();
Calendar cal = Calendar.getInstance();
for(int i=0;i< arraylist.size();i++) {
cal.setTimeInMillis(arraylist.getTimeStamp());
timestampsList.add(DateFormat.format("kk:mm", cal).toString());
}
Any help will be appreciated!! Thanks
I don't know the static method DateFormat.format(...) - is this an android specific class you are using?
I would assume however that the implementation creates a new format object for the pattern you specify and uses it to format the given calendar.
You could try creating the format object before the loop, see SimpleDateFormat, and then use it inside the loop.
int size = arraylist.size();
String[] timestampsList = new String[size];
java.text.DateFormat format = SimpleDateFormat("kk:mm");
for(int i = 0; i < size; i++) {
Date date = arraylist.get(i).??? ;
timestampsList[i] = format.format(date);
}
Note that the format object you created should not be shared between threads so do not store in a static field.
Also note that Calendar calculations might also be computation intensive, it could be that this is also slowing things down, but if you use SimpleDateFormat directly you can just use raw dates.
You might want also to set the timezone on your format object.
Issue was in DateFormat method.Finally, i used Joda-Time library to convert my date which took 612 ms only..Awesome improvement.
// this one took 612 ms to convert 12600 records
Joda-Time library 2.3 version
private static final DateTimeFormatter dateTimeFormatter = DateTimeFormat.forPattern("kk:mm");
private static DateTime dateTime = new DateTime();
public String getFormattedLabel(long timeStamp) {
dateTime = dateTime.withMillis(timeStamp);
return dateTime.toString(dateTimeFormatter);
}
and used it like -:
ArrayList<String> timestampsList = new ArrayList<String>();
Calendar cal = Calendar.getInstance();
for(int i=0;i< arraylist.size();
timestampsList.add(getFormattedLabel(arraylist.getTimeStamp());
}
Let's say I have this:
PrintStream out = System.out;
Scanner in = new Scanner(System.in);
out.print("Enter a number ... ");
int n = in.nextInt();
I have a random date, for example, 05/06/2015 (it is not a fixed date, it is random every time). If I want to take the 'year' of the this date, and add whatever 'n' is to this year, how do i do that?
None of the methods in the Date Class are 'int'.
And to add years from an int, 'years' has to be an int as well.
You need to convert the Date to a Calendar.
Calendar c = Calendar.getInstance();
c.setTime(randomDate);
c.add(Calendar.YEAR, n);
newDate = c.getTime();
You can manipulate the Year (or other fields) as a Calendar, then convert it back to a Date.
This question has long deserved a modern answer. And even more so after Add 10 years to current date in Java 8 has been deemed a duplicate of this question.
The other answers were fine answers in 2012. The years have moved on, today I believe that no one should use the now outdated classes Calendar and Date, not to mention SimpleDateFormat. The modern Java date and time API is so much nicer to work with.
Using the example from that duplicate question, first we need
private static final DateTimeFormatter formatter
= DateTimeFormatter.ofPattern("uuuu-MM-dd HH:mm:ss");
With this we can do:
String currentDateString = "2017-09-12 00:00:00";
LocalDateTime dateTime = LocalDateTime.parse(currentDateString, formatter);
dateTime = dateTime.plusYears(10);
String tenYearsAfterString = dateTime.format(formatter);
System.out.println(tenYearsAfterString);
This prints:
2027-09-12 00:00:00
If you don’t need the time of day, I recommend the LocalDate class instead of LocalDateTime since it is exactly a date without time of day.
LocalDate date = dateTime.toLocalDate();
date = date.plusYears(10);
The result is a date of 2027-09-12.
Question: where can I learn to use the modern API?
You may start with the Oracle tutorial. There’s much more material on the net, go search.
Another package for doing this exists in org.apache.commons.lang3.time, DateUtils.
Date date = new Date();
date = DateUtils.addYears(date, int quantity = 1);
The Date class will not help you, but the Calendar class can:
Calendar cal = Calendar.getInstance();
Date f;
...
cal.setTime(f);
cal.add(Calendar.YEAR, n); // Where n is int
f = cal.getTime();
Notice that you still have to assign a value to the f variable. I frequently use SimpleDateFormat to convert strings to dates.
Hope this helps you.
Try java.util.Calendar type.
Calendar cal=Calendar.getInstance();
cal.setTime(yourDate.getTime());
cal.set(Calendar.YEAR,n);
This will add 3 years to the current date and print the year.
System.out.println(LocalDate.now().plusYears(3).getYear());
If you need add one year a any date use the object Calendar.
Calendar dateMoreOneYear = Calendar.getInstance();
dateMoreOneYear.setTime(dateOriginal);
dateMoreOneYear.add(Calendar.DAY_OF_MONTH, 365);
Try like this as well for a just month and year like (June 2019)
Calendar cal = Calendar.getInstance();
cal.add(Calendar.YEAR, n); //here n is no.of year you want to increase
SimpleDateFormat format1 = new SimpleDateFormat("MMM YYYY");
System.out.println(cal.getTime());
String formatted = format1.format(cal.getTime());
System.out.println(formatted);
Try this....
String s = new SimpleDateFormat("YYYY").format(new Date(random_date_in_long)); //
int i = Integer.parseInt(s)+n;
First of all forgive my English :-(
I have a problem with hours on java. Let's see it by an example:
DateFormat datos = new SimpleDateFormat ("hh:mm:ss");
Date ac, lim;
String actual,limit;
actual="18:01:23";
limit="00:16:23";
ac=datos.parse(actual);
lim=datos.parse(limit);
if(ac.compareTo(lim)==-1){.......
I need to solve this case in which limit is past midnight and actual hour is before midnight. My program says that actual has reached limit and it isn't correct because at the example, it has still 6 hours to finish.
I tried to solve it with DateFormat class but it doesnt see this case. I tried it with Time class too but its methods are deprecated.
How can I solve this?
Use HH instead of hh in your SimpleDateFormat:
DateFormat datos = new SimpleDateFormat("HH:mm:ss");
hh is the 12-hour clock (hours go from 1 to 12).
HH is the 24-hour clock (hours go from 0 to 23).
But besides that, there are other things wrong with this. Class Date is not very well suited to contain only a time. If you do this, it will be parsed as 01-01-1970 with the specified time. So 18:01:23 becomes 01-01-1970, 18:01:23 and 00:16:23 becomes 01-01-1970, 00:16:23. You probably wanted to compare 18:01:23 to 00:16:23 the next day.
Try something like this:
String actual = "18:01:23";
String limit = "00:16:23";
String[] parts = actual.split(":");
Calendar cal1 = Calendar.getInstance();
cal1.set(Calendar.HOUR_OF_DAY, Integer.parseInt(parts[0]));
cal1.set(Calendar.MINUTE, Integer.parseInt(parts[1]));
cal1.set(Calendar.SECOND, Integer.parseInt(parts[2]));
parts = limit.split(":");
Calendar cal2 = Calendar.getInstance();
cal2.set(Calendar.HOUR_OF_DAY, Integer.parseInt(parts[0]));
cal2.set(Calendar.MINUTE, Integer.parseInt(parts[1]));
cal2.set(Calendar.SECOND, Integer.parseInt(parts[2]));
// Add 1 day because you mean 00:16:23 the next day
cal2.add(Calendar.DATE, 1);
if (cal1.before(cal2)) {
System.out.println("Not yet at the limit");
}
The library Joda Time is a popular Java date and time library that is much better designed than the standard Java date and calendar API; consider using it if you have to work with dates and times in Java.
With Joda Time you could do this:
String actual = "18:01:23";
String limit = "00:16:23";
DateTimeFormatter df = DateTimeFormat.forPattern("HH:mm:ss");
DateTime ac = df.parseLocalTime(actual).toDateTimeToday();
DateTime lim = df.parseLocalTime(limit).toDateTimeToday().plusDays(1);
if (ac.isBefore(lim)) {
System.out.println("Not yet at the limit");
}
As a quick and dirty solution:
final DateFormat datos = new SimpleDateFormat("HH:mm:ss");
Date ac;
final Date lim = new Date();
String actual, limit;
actual = "18:01:23";
limit = "00:16:23";
try {
ac = datos.parse(actual);
lim.setTime(ac.getTime() + TimeUnit.MINUTES.toMillis(16) + TimeUnit.SECONDS.toMillis(23));
if ( ac.before(lim) ) {
// TODO
}
} catch ( final ParseException e ) {
e.printStackTrace();
}