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convert xmlGregorianCalendar to Date and reverse

i all, i have a spring boot application. what i want in specific is to convert a class (that have nestet object field) in his corrispective entity. example:
public class example{
String string;
ObjectExample object;
}
public class ObjectExample{
String oneString;
XMLGregorianCalendar date;
}
this 2 object are also marked in another package as entities, but ovviusly in the ObjectExampleEntity i have Date date instead XMLGregorianCalendar, like this with the example
#Entity
public class example{
String string;
ObjectExample object;
}
#Entity
public class ObjectExample{
String oneString;
Date date;
}
because i have a big model and big entity (this above is only an example) with a lot of nested classes , i use dozer to convert from the model to the class.
consider for example that the repository jpa is only created for the father example class.
i want to know how i can with dozer convert from Date (entity) to XMLGregorianCalendar (model) and reverse. the model and the entity,i repeat are equal. the only difference is the type of the date. thanks

I am assuming:
Since your variable is named date it contains a calendar date (without time of day).
You are tied to XMLGregorianCalendar because of a WSDL outside your control, but you can change type on the entity side.
Based on these assumptions I recommend LocalDate on the entity side. It’s part of java.time, the modern Java date and time API, and represents exactly a date without time of day. The Date class that you used is poorly designed, long outdated and not recommended. Also despite the name a Date never represented a date, but a point in time.
There are more options. I am presenting three.
Option 1: transfer individual fields
From XMLGregorianCalendar to LocalDate:
DatatypeFactory xmlFactory = DatatypeFactory.newInstance();
XMLGregorianCalendar wsDate = xmlFactory
.newXMLGregorianCalendarDate(2019, DatatypeConstants.MARCH, 30,
DatatypeConstants.FIELD_UNDEFINED);
// Validate
if ((wsDate.getHour() != 0 && wsDate.getHour() != DatatypeConstants.FIELD_UNDEFINED)
|| (wsDate.getMinute() != 0 && wsDate.getMinute() != DatatypeConstants.FIELD_UNDEFINED)
|| (wsDate.getSecond() != 0 && wsDate.getSecond() != DatatypeConstants.FIELD_UNDEFINED)
|| (wsDate.getMillisecond() != 0 && wsDate.getMillisecond() != DatatypeConstants.FIELD_UNDEFINED)) {
System.out.println("Warning: time of day will be lost in conversion");
}
if (wsDate.getTimezone() != DatatypeConstants.FIELD_UNDEFINED) {
System.out.println("Warning: UTC offset will be lost in conversion");
}
// Convert
LocalDate entityDate = LocalDate.of(wsDate.getYear(), wsDate.getMonth(), wsDate.getDay());
System.out.println(entityDate);
The output is in this case:
2019-03-30
From LocalDate to XMLGregorianCalendar:
LocalDate entityDate = LocalDate.of(2019, Month.MARCH, 31);
XMLGregorianCalendar wsDate = xmlFactory.newXMLGregorianCalendarDate(
entityDate.getYear(),
entityDate.getMonthValue(),
entityDate.getDayOfMonth(),
DatatypeConstants.FIELD_UNDEFINED);
System.out.println(wsDate);
2019-03-31
Advantage of this way: It’s pretty straightforward. Disadvantage: You and your reader need to take care that the fields are mentioned in the right order.
Option 2: convert via strings
// Validate as before
// Convert
LocalDate entityDate = LocalDate.parse(wsDate.toXMLFormat());
Result is as before.
XMLGregorianCalendar wsDate
= xmlFactory.newXMLGregorianCalendar(entityDate.toString());
Advantage: it’s brief, and there’s no surprise that the results are correct. Disadvantage: To me it feels like a waste to format into a string only to parse it back.
Option 3: convert via GregorianCalendar and ZonedDateTime
ZonedDateTime zdt = wsDate.toGregorianCalendar().toZonedDateTime();
// Validate
if (! zdt.toLocalTime().equals(LocalTime.MIN)) {
System.out.println("Warning: time of day will be lost in conversion");
}
if (! zdt.getZone().equals(ZoneId.systemDefault())) {
System.out.println("Warning: UTC offset will be lost in conversion");
}
// Finish conversion
LocalDate entityDate = zdt.toLocalDate();
And the other way:
// It doesn’t matter which time zone we pick
// since we are discarding it after conversion anyway
ZonedDateTime zdt = entityDate.atStartOfDay(ZoneOffset.UTC);
GregorianCalendar gCal = GregorianCalendar.from(zdt);
XMLGregorianCalendar wsDate = xmlFactory.newXMLGregorianCalendar(gCal);
wsDate.setTime(DatatypeConstants.FIELD_UNDEFINED, DatatypeConstants.FIELD_UNDEFINED,
DatatypeConstants.FIELD_UNDEFINED, DatatypeConstants.FIELD_UNDEFINED);
wsDate.setTimezone(DatatypeConstants.FIELD_UNDEFINED);
The validation I present here is a bit simpler but also not quite so strict. If you want strict validation, you can just use the validation from before.
Advantages: I think it’s the official way; at least it uses the conversion methods offered. What I like is that the conversion itself is direct and brief. Disadvantage: When converting to XMLGregorianCalendar we need to set the unused fields to undefined manually, which makes it wordy.
Conclusion
I have presented three options each with their pros and cons. You may also mix, of course, but using a similar conversion both ways is probably less confusing in the end.

Java Unit Testing method that uses new Date() for current date [duplicate]

This question already has answers here:
Unit testing time-based logic in Java
(3 answers)
Handling unit tests with a condition on the current time
(6 answers)
Setting time and date in JUnit test fixture
(4 answers)
Writing and testing convenience methods using Java 8 Date/Time classes
(1 answer)
Closed 3 years ago.
So I have a class that has a method "getDaysUntil(Date date)" which returns the number of days until the date given as parameter. I mention that I cannot change the class below:
public class A {
public int getDaysUntil(Date givenDate) {
... // code
Date currentDate = new Date() //it creates a date object holding the current day
...// code that calculates the nr of days between currentDate and givenDate.
}
I have to do some unit testing and you might see the problem, it creates currentDate inside the method and the returned value will be different from day to day. I have tried to mock a Date object or "override" System.currentTimeMillis() with PowerMock but to no avail.
Is there any way to properly test these kind of methods?

Use a class that serves as a DateFactory, which is called to construct Date objects in your application code.
Then just mock the method of that DateFactory in your unit test. That way you can make it return whatever date you want as a virtual "current date"

One solution where System.currentTimeMillis() is mocked is as follows, using the JMockit library (it should be possible with PowerMock too):
#Test #SuppressWarnings("deprecation")
public void daysUntilCurrentDate() {
final long fakeCurrentDateInMillis = new Date(2017, 2, 1).getTime();
new MockUp<System>() {
#Mock long currentTimeMillis() { return fakeCurrentDateInMillis; }
};
A tested = new A();
int daysSinceJan30 = tested.getDaysUntil(new Date(2017, 1, 30));
assertEquals(2, daysSinceJan3O);
}

I understand that you cannot change the method that you need to test. Unfortunately this also means that you are stuck with the old and often not very programmer-friendly Date class (I am assuming java.util.Date).
Edit: The no-arg Date constructor that your method uses in turn uses System.currentTimeMillis(), a static native method. I didn’t know there were tools that could mock contructors and static native methods, but was informed by comment and answer by #Rogério, the developer of JMockit, that such mocking tools exist.
In any case, there is an alternative: you calculate some number of days from today, pass the resulting Date to the method and check that you get the number back you used in your calculation. This will work on any day and requires no mocking/stubbing.
In the code below I am assuming that the getDaysUntil method should discard the hours and minutes and just look at the date in the computer’s time zone. If the real requirements differ, you can probably make the appropriate adjustments to my code.
We want to take into account that the method may run over midnight. If so, I consider the result undefined since we do not know whether the Date object was constructed before or after midnight. In this case I simply try again, assuming the test will finish before the next midnight.
#Test
public void testGetDaysUntil() {
A instanceUnderTest = new A();
for (int daysToTest = 0; daysToTest <= 400; daysToTest++) {
LocalDate today;
int result;
do {
today = LocalDate.now(); // do this in each iteration in case day changes underway
LocalDate targetDate = today.plusDays(daysToTest);
Date midnightAtStartOfDay = Date.from(targetDate.atStartOfDay(ZoneId.systemDefault())
.toInstant());
result = instanceUnderTest.getDaysUntil(midnightAtStartOfDay);
} while (! today.equals(LocalDate.now())); // if we have passed midnight, try again
assertEquals(daysToTest, result);
do {
today = LocalDate.now();
LocalDate targetDate = today.plusDays(daysToTest);
Date nearMidnightAtEndOfDay = Date.from(targetDate.atTime(23, 59, 59, 400_000_000)
.atZone(ZoneId.systemDefault())
.toInstant());
result = instanceUnderTest.getDaysUntil(nearMidnightAtEndOfDay);
} while (! today.equals(LocalDate.now()));
assertEquals(daysToTest, result);
}
}
I have used the Java 8 classes for the date and time calculations. If you cannot use Java 8, Calendar and/or GregorianCalendar can be used, they may be just a little more cumbersome for this job, but at least can be converted to Date easily.

Does Joda-Time have a method called isToday

I need to check if a given timestamp is today. I am using Joda-Time. Is there a method or a simple way to check this? What Joda-Time class is better suited for this? LocalDate? DateTime?

The date can be compared by single statement so why you need a special function.
when dateTimeis an object of DateTime()
if((dateTime.toLocalDate()).equals(new LocalDate()))
when date is an object of java.util.date
if((new DateTime(date).toLocalDate()).equals(new LocalDate()))
What Joda-time class is better suited for this? LocalDate? DateTime?
The understanding that you need to know what is LocalDate and DateTime.
LocalDate() is an immutable datetime class representing a date without a
time zone. So is not having a time part.
DateTime() is the standard implementation of an unmodifiable datetime
class. Its having all the attributes of the Date, which includes
date, time and timezone.
So if you need to compare both the date and time better go with datetime, if you just need to check the date you must use localDate because the datetime will produce a false if an .equal operator is used, unless the time including the seconds part are same for both the objects.

Here are some simple methods to check if a DateTime is today, tomorrow or yesterday:
public boolean isToday(DateTime time) {
return LocalDate.now().compareTo(new LocalDate(time)) == 0;
}
public boolean isTomorrow(DateTime time) {
return LocalDate.now().plusDays(1).compareTo(new LocalDate(time)) == 0;
}
public boolean isYesterday(DateTime time) {
return LocalDate.now().minusDays(1).compareTo(new LocalDate(time)) == 0;
}

One possibility is to create an interval covering the whole day in question, and then check if the various timestamps are contained in this interval.
Constructing the initial interval could look like:
Interval today = new Interval(DateTime.now().withTimeAtStartOfDay(), Days.ONE);
Then the timestamps could be checked like so:
today.contains(DateTime.now()); // True
today.contains(DateTime.now().minusDays(1)); // False
today.contains(DateTime.now().plusDays(1)); // False
today.contains(someOtherTimeStamp.toDateTime()); // And so on...

The recommended way to do this would be:
DateTime midnightToday = DateTime.now().withTimeAtStartOfDay();
DateTime myDateTime = <whatever>;
if(myDateTime.isAfter(midnightToday)) {
}
I think you need Joda 2.5 to do this, but that should do the trick.

I like #JustinMorris's answer. But I found this even better:
public static boolean isToday(DateTime time) {
return LocalDate.now().equals(new LocalDate(time));
}
public static boolean isTomorrow(DateTime time) {
return LocalDate.now().plusDays(1).equals(new LocalDate(time));
}
public static boolean isYesterday(DateTime time) {
return LocalDate.now().minusDays(1).equals(new LocalDate(time));
}

AFAIK there is no direct method available by which you can check the Date is Today Date or not.
The simplest approach will be constructing two DateTime one with the Timestamp, and another with today Date and then comparing day from dayOfYear() and year from year() but do remember whether both Date are in UTC or in Local Time Zone.
A small sample,
DateTime date = new DateTime(TimeStamp);
DateTime todayDate = new DateTime();
if(date.dayOfYear().get() == todayDate.dayOfYear().get() && date.year().get() == todayDate.year().get())
{
System.out.println("Date is today date");
}

Joda time actually have a method for this:
DateUtils#isToday(ReadablePartial);
DateUtils#isToday(ReadableInstant);

Simplest way I've found:
public boolean isToday(DateTime dateTime) {
return dateTime.withTimeAtStartOfDay().getMillis() ==
new DateTime().withTimeAtStartOfDay().getMillis();
}

Add time unit to Joda DateTime object

Is there a better way to add a certain unit of time to a DateTime object?
I would like to do something similar to:
TimeUnit unit = TimeUnit.valueOf("days");
DateTime date = new DateTime().add(unit, 20);
This is my current implementation.
int number = 20;
MutableDateTime now = new MutableDateTime();
String timeUnit = getTimeUnit(); // returns "days", "months", "years"
if (timeUnit.equals("days"))
now.addDays(number);
else if (timeUnit.equals("months"))
now.addMonths(number);
else
now.addYears(number);
return now.toDateTime();

The answer of Sotirios Delimanolis is right. JodaTime has no enum-like concept because it was developed before the introduction of Java generics and enums in JDK5. In Java 8 you can also go this way or similar:
String name = "days"; // or months or years
ChronoUnit unit = ChronoUnit.valueOf(name.toUpperCase());
LocalDateTime ldt = LocalDateTime.of(...);
ldt = ldt.plus(number, unit);
Or consider using ZonedDateTime instead of LocalDateTime. The new approach is much more elegant (yes JodaTime becomes old).

I don't know of a built-in way to do it. Instead, you can create a Map of String names mapped to corresponding DurationFieldType objects. For example
static Map<String, DurationFieldType> durationFieldTypes = new HashMap<>();
static {
durationFieldTypes.put("days", DurationFieldType.days());
durationFieldTypes.put("months", DurationFieldType.months());
...
}
And then just query that Map for the appropriate object
MutableDateTime dateTime = new MutableDateTime();
String timeUnit = getTimeUnit(); // returns "days", "months", "years"
dateTime.add(durationFieldTypes.get(timeUnit), amount);
You will possibly need some fail safe for invalid timeUnit values.

Java system time

I have this code copied from one of questions from SO:
public static String getCurrentTimeStamp() {
SimpleDateFormat sdfDate = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
Date now = new Date();
String strDate = sdfDate.format(now);
return strDate;
}
I want to get only the system time and NOT the date. Then I must change second line of code to:
SimpleDateFormat sdfDate = new SimpleDateFormat(" HH:mm:ss") ;
Then, DATE() must get the current time. Clear upto this point but I can't understand the format() function used.
I mean cant we simply output variable now instead of strdate?
Is it just because that the return type of function getCurrentTimeStamp() is String?
Please clarify and if there is any other simpler and one line code for getting system time alone, do share.

I mean cant we simply output variable now instead of strdate.
Well you could return now.toString() - but that will use the format that Date.toString() happens to choose, whereas you want a specific format. The point of the SimpleDateFormat object in this case is to convert a Date (which is a point in time, without reference to any particular calendar or time zone) into a String, applying an appropriate time zone, calendar system, and text format (in your case HH:mm:ss).
You can still simplify your method somewhat though, by removing the local variables (which are each only used once):
public static String getCurrentTimeStamp() {
return new SimpleDateFormat("HH:mm:ss").format(new Date());
}
Or maybe you'd find it more readable to keep the variable for the date format, but not the date and the return value:
public static String getCurrentTimeStamp() {
DateFormat format = new SimpleDateFormat("HH:mm:ss");
return format.format(new Date());
}
Personally I'd recommend using Joda Time instead, mind you - it's a much nicer date/time API, and its formatted are thread-safe so you could easily keep a reference to a single formatting object.

public static String getCurrentTimeStampwithTimeOnly() {
return new SimpleDateFormat("HH:mm:ss").format(new Date());
}
Helps you to do this.

you can call this line any time
Date now = new Date();
The now variable will contain the current timestamp
The format function just generates a String from this timestamp
also take a look at the Calendar class ( Calendar.getInstance())