I have a method to calculate the expiry date given manufacturing date of format("yyyy-MM-dd") and the months before the product could be used in int.First I tried with getYear getMonth getDate of Month class as follows I dint got errors results:
public void calculateExpiryDate(List<Item> items)
{
Iterator<Item> itr=items.iterator();
while(itr.hasNext())
{
Item i=itr.next();
Date md=i.getManufacturingDate();
int ubm=i.getUseBeforeMonths();
Calendar c=new GregorianCalendar(md.getYear(),md.getMonth(),md.getDate());
//System.out.println(c);
c.add(Calendar.MONTH, ubm);
Date exp=c.getTime();
i.setExpiryDate(exp);
SimpleDateFormat sdf=new SimpleDateFormat("yyyy MM dd");
System.out.println(md+" "+ubm+" "+sdf.format(exp)+" "+" "+i.getId());
}
}
But when I Quit using it and used setTime instead it solved my problem.I want to know what mistake I was making before and why things don't work that day and if any mistake(cause I was not getting any compile time errors) what is it actually.Following is the version of same code giving proper results.
public void calculateExpiryDate(List<Item> items)
{
Iterator<Item> itr=items.iterator();
while(itr.hasNext())
{
Item i=itr.next();
Date md=i.getManufacturingDate();
int ubm=i.getUseBeforeMonths();
Calendar c=new GregorianCalendar();
c.setTime(md);
//System.out.println(c);
c.add(Calendar.MONTH, ubm);
Date exp=c.getTime();
i.setExpiryDate(exp);
SimpleDateFormat sdf=new SimpleDateFormat("yyyy MM dd");
System.out.println(md+" "+ubm+" "+sdf.format(exp)+" "+" "+i.getId());
}
}
Your problem is that the constructor for GregorianCalendar expects the year as absolute value, but getYear() returns an offset to 1900.
A look into to the Java documentation reveals (beside that the used Date methods are all deprecated):
Date.getYear():
returns a value that is the result of subtracting 1900 from the year that contains or begins with the instant in time represented by this Date object, as interpreted in the local time zone.
GregorianCalendar:
year constructor parameter the value used to set the YEAR calendar field in the calendar
Whereas setTime(Date) used the value returned by md.getTime() which is number of milliseconds since January 1, 1970, 00:00:00 GMT.
Related
This question already has answers here:
Comparing two java.util.Dates to see if they are in the same day
(14 answers)
How to know if a Date is within the same day of other date [duplicate]
(2 answers)
Closed 6 years ago.
According to Java API public boolean before(Date when)
true if and only if the instant of time represented by this Date
object is strictly earlier than the instant represented by when; false
otherwise.
Now I have to check if date input by user is greater than current date then only it will accept the input otherwise throw exception so i tried below
if(userInputDate.before(new Date())){
throw new Exception("Some Message");
}
But if both date are same then also it going to inside if statement .Do it mean it will calculate time and then check rather than comparing date? If yes how to resolve my issue ?
Can any one tell me how to add check for this?
The method before in the class Date is comparing the millisecond between the dates, so it's not comparing just the day, it is comparing the instant of time.
You could create a method to check if the dates are not in the same day and the first date is before the second one
public static boolean isBeforeDate(Date date1, Date date2) {
SimpleDateFormat fmt = new SimpleDateFormat("yyyyMMdd");
boolean areTheSameDay = fmt.format(date1).equals(fmt.format(date2));
return !areTheSameDay && date1.before(date2);
}
If you can use the new time api In Java8 instead of the old Date class, you can use the class LocalDate and the method compareTo:
boolean isBefore = myLocalDate.compareTo(myOtherLocalDate) < 0
All methods on java.util.Date that allow one to separate the time of day from the day of the year are deprecated. Therefore it is better to use java.util.Calendar. Additionally one should consider that there is typically one hour in each year that is in two days when summer time ends.
Here are two ways you can do it:
public static boolean isBeforeDay(Date date1, Date date2) {
// convert date1 to noon on the same day
Calendar day1 = Calendar.getInstance(TimeZone.getDefault());
day1.setTime(date1);
day1.set(Calendar.HOUR_OF_DAY, 12);
day1.set(Calendar.MINUTE, 0);
day1.set(Calendar.SECOND, 0);
day1.set(Calendar.MILLISECOND, 0);
// convert date2 to noon on the same day
Calendar day2 = Calendar.getInstance(TimeZone.getDefault());
day2.setTime(date2);
day2.set(Calendar.HOUR_OF_DAY, 12);
day2.set(Calendar.MINUTE, 0);
day2.set(Calendar.SECOND, 0);
day2.set(Calendar.MILLISECOND, 0);
return day1.before(day2);
}
public static boolean isBeforeDay(Date date1, Date date2) {
// get yyyymmdd value from date1
Calendar day1 = Calendar.getInstance(TimeZone.getDefault());
day1.setTime(date1);
int ymd1 = 10000*day1.get(Calendar.YEAR) + 100*day1.get(Calendar.MONTH) + day1.get(Calendar.DAY_OF_MONTH);
// get yyyymmdd value from date2
Calendar day2 = Calendar.getInstance(TimeZone.getDefault());
day2.setTime(date2);
int ymd2 = 10000*day2.get(Calendar.YEAR) + 100*day2.get(Calendar.MONTH) + day2.get(Calendar.DAY_OF_MONTH);
return ymd1 < ymd2;
}
This's my datebox
<datebox value="#bind(vm.myDate)" format="d/M/yyyy hh:mm"/>
I can change day, month, year and minutes, accepted hour. it default to current hour, when I change to other hour it reset to that value.
on my vm myDate is type of java.util.Date
Date myDate;
public Date getMyDate(){
return myDate;
}
public void setMyDate(Date myDate){
this.myDate = myDate;
}
ZK cannot decide whether you are meaning AM or PM on input. And therefore - my interpretation - it does nothing.
You can either add an AM/PM input element like
format="d/M/yyyy a hh:mm"
or you can set the 24h format:
format="d/M/yyyy HH:mm"
This question already has answers here:
Get yesterday's date using Date [duplicate]
(8 answers)
Closed 8 years ago.
I've got an object with a field timestamp with type java.sql.Timestamp;.
And I need to get objects with yesterday date from a collection.
How to get them?
I mean I need something like this
for(int i = 0; i < items.size(); i++) {
(if the items.get(i).date == yesterday_date)
(get object)
}
You can get yesterday's Date by following approach Answered by Jiger Joshi.
And by using new Timestamp(java.util.Date) you can get yesterday's timestamp, you should use Timestamp#equals to equaling two different timestamp.
if (items.get(i).date.equals(getYesterdaytimestamp())){
...
}
And there are something which you must consider while implementing this. Calender#getTime which returns Date object and date object contains date with time, so in that case your equaling date or timestamp must be exactly equals with yesterday's date and time.
If requirement is, it needs to equal just yesterday no not where time is not considerable fact. In that case you need to equals two timestamp after discarding time part.
if (equalsWithYesterday(items.get(i).date)){
...
}
...
public boolean equalsWithYesterday(Timestamp st){
DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd"); // Time part has discarded
Calendar cal = Calendar.getInstance();
cal.add(Calendar.DATE, -1);
Date yesterday = dateFormat.parse(dateFormat.format(cal.getTime())); // get yesterday's Date without time part
Date srcDate = new Date(st);
Date srcDateWithoutTime =dateFormat.parse(dateFormat.format(srcDate));
return yesterday.equals(srcDateWithoutTime ); // checks src date equals yesterday.
}
You can convert the timestamp object to date object like this:
Date date = new Date(items.get(i).getTime());
or you can simply use method Timestamp#compareTo(Date o)
items.get(i).compareTo(yesterday_date);
I hope you are not interested to compare the time?
Simply use Calendar class to extract the day, month, year etc. from the date and simply compare it.
Use Calendar#get() method to get the specific field from the date object.
How to subtract one day from the current date?
// get Calendar with current date
Calendar cal = Calendar.getInstance();
// get yesterday's date
cal.add(Calendar.DATE, -1);
// get components of yesterday's date
int month = cal.get(Calendar.MONTH) + 1; // 0 for January, 1 for Feb and so on
int day = cal.get(Calendar.DATE);
int year = cal.get(Calendar.YEAR);
// get yesterday's date in milliseconds
long lMillis = cal.getTime().getTime();
I need to set some days in method set. I try to use:
c.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
c.set(Calendar.DAY_OF_WEEK, Calendar.WEDNESDAY);
but with this way set only Wednesday.
Thank you and sorry for my english :)
The Calendar does not function as you expect it to. From the JavaDoc:
The Calendar class is an abstract class that provides methods for
converting between a specific instant in time and a set of calendar
fields such as YEAR, MONTH, DAY_OF_MONTH, HOUR, and so on, and for
manipulating the calendar fields, such as getting the date of the next
week. An instant in time can be represented by a millisecond value
that is an offset from the Epoch, January 1, 1970 00:00:00.000 GMT
(Gregorian).
Notice that the documentation states a specific instant in time. This implies the Calendar can only be based off of one point in time from epoch.
When you use the set method you are adjusting the specific instant in time through each call. So first it gets set to Monday then Wednesday.
You could use a List<Calendar> to store multiple Calendar instances set to your desired days.
public class CalendarTest {
public static void main(String[] args) {
Calendar cal1 = Calendar.getInstance();
Calendar cal2 = Calendar.getInstance();
cal1.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
cal2.set(Calendar.DAY_OF_WEEK, Calendar.WEDNESDAY);
List<Calendar> calendars = Arrays.asList(cal1, cal2);
}
}
public static String getDay(String day,String month,String year){
int mm = Integer.parseInt(month);
int dd = Integer.parseInt(day);
int yy = Integer.parseInt(year);
LocalDate dt = LocalDate.of(yy, mm, dd);
return dt.getDayOfWeek().toString().toUpperCase();
}
My program needs to represent this date as a java.sql.date object , but it seems that when I create a new date (using the calendar) and set it to '9999-12-31' and finally convert this java.util.date object to a java.sql.date object, this date is converted to something like '000-01-31'.
Calendar calendar = Calendar.getInstance();
calendar.set(9999, 12, 31);
infinityDate = new java.sql.Date(normalizeDate(calendar.getTime()).getTime());
infinityDate should be 31-12-9999
but when my code reaches here :
if(otherDate.equals(infinityDate))
{// Do stuff}
It never goes into the if condition as the infinityDate has for some reason been changed to 31-01-000, even though otherDate is infact '31-12-9999'.
The fact that otherDate is 31-12-9999 tells me that java can represent this dates , but for some reason , when I construct it using a calendar it changes the date. (otherDate comes from a jdbc statement which fetches data from a database)
This reference date '31-12-9999' has been fixed by some client , so it cannot be changed and my program has to be able to compare some incoming date values with this.
Does anyone know why this is happening , I realize that http://en.wikipedia.org/wiki/Year_10,000_problem may be a problem for dates after year 9999 , but I should be safe by a day.
EDIT : The Normalize date method only "normalizes the given date to midnight of that day"
private static java.util.Date normalizeDate(java.util.Date date) {
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
calendar.set(Calendar.HOUR_OF_DAY, 0);
calendar.set(Calendar.MINUTE, 0);
calendar.set(Calendar.SECOND, 0);
calendar.set(Calendar.MILLISECOND, 0);
date = calendar.getTime();
return date;
}
But , this issue was appearing before I was normalizing the date , I normalized it in an attempt to fix this.
Months are zero indexed. Use 11 for December, not 12. This is why you are rolling over the year.
Calendar.MONTH is zero-based. The call
calendar.set(9999, 12, 31);
sets the date to "the 31st day in the 13th month of the year 9999", which is then implicitly converted to the 1st month of the year 10000. It would result in an exception if you first called
calendar.setLenient(false);
Check hours, minutes, seconds and milliseconds that are held into these 2 date objects. I believe they are different.
If your want to compare the date (year, month, day) only you should probably create your custom Comparator and use it.