Typecast sql.date to calendar - java

I have some code that uses the sql.date object to get the current date in the format: yyyy-MM-dd. I want to typecast that to a Calendar object that has the same format as the sql.date.
Here is the code for the sql.date:
java.util.Date now = new java.util.Date();
java.sql.Date sqlDate = new java.sql.Date( now.getTime() );
Edit:
I want to know how to put this in a Calendar object. Is it even possible to do this?

A java.sql.Date doesn't have a format. It's just a date.
To convert it to a string, use a SimpleDateFormatter with the relevant format set - or just use toString if you definitely want yyyy-MM-dd. (Unfortunately it's unclear which time zone you should use - java.sql.Date is very poorly documented in this respect. I suspect it will use the default system time zone.)
To create a Calendar object with the given date, you can just use:
Calendar calendar = Calendar.getInstance();
calendar.setTime(sqlDate);
Again, a Calendar doesn't have a text format either - it represents a point in time in a particular calendar system in a particular time zone, but nothing about a textual representation.

Use SimpleDateFormat#format()
System.out.println(new SimpleDateFormat("yyyy-MM-dd")
.format(Calendar.getInstance().getTime()));

Java Date objects (and note that java.sql.Date is a java.util.Date) don't have "formats". They represent an instant in time.
Calendar also doesn't have a "format".
What you're asking for doesn't make sense in java.
Consider using SimpleDateFormat to format one of these things into a String:
String str = new SimpleDateFormat("yyyy-MM-dd").format(myDate);
or if you use a Calendar object (not recommended):
String str = new SimpleDateFormat("yyyy-MM-dd").format(myCalendar.getTime());

You can use the following snippet.
public class DateTest {
public static void main(String[] arg){
Calendar calendar = Calendar.getInstance();
//setting a valid date
Date date = new Date(113,07,10);
//prints the date as per format
System.out.println("Date in YYYY-MM-DD : " +date);
//sets the calendar with the date value in java.sql.Date instance
calendar.setTime(date);
//use simple date formatter to format the value in calendar instance
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
System.out.println("Date formatted from Calendar instance : "+dateFormat.format(calendar.getTime()));
}
}
Please let me know what happens!

Related

Time String to time representation Java

I have a string like this 210115 I want to represent it as 21:01:15 any ideas?.
I tried using Gregorian calendar but it adds date to it which I don't want
SimpleDateFormat sdf = new SimpleDateFormat("HHmmss");
Date date = new Date();
try{
date = sdf.parse("210115");
}
catch(Exception e){
}
Calendar calendar = GregorianCalendar.getInstance();
calendar.setTime(date);
System.out.print(calendar.getTime());
Output is Thu Jan 01 21:01:15 UTC 1970 but what I want is just 21:01:15
Thanks.
To output a formatted date, you use another SimpleDateFormat object with a pattern with the format you want.
In this case, it sounds like you might want to use something like
SimpleDateFormat outputFormat = new SimpleDateFormat("HH:mm:ss");
System.out.println( outputFormat.format(date) );
So what you want is just a time, without time zone. I would recommend using the LocalTime class, which is exactly that, instead of the Date class.
LocalTime time = LocalTime.parse("210115", DateTimeFormatter.ofPattern("HHmmss"));
If u r getting the date string in "210115" this format and you want it in "21:01:15" format then why are you using date format.
Simply do string operation as:
String time="210115";
String newtime=time.substring(0,2)+":"+time.substring(2,4)+":"+time.substring(4,6);
System.out.println(newtime);
you will get the required format.21:01:15

Java Date which looks same in any timezone

I am currently trying to get create a java Date which looks the same no matter what timezone I view it in. My current code is:
Calendar cal = Calendar.getInstance();
cal.set(2015, Calendar.JANUARY, 8, 0, 0, 0);
cal.set(Calendar.MILLISECOND, 0);
Date date = cal.getTime();
In my current timeZone this gives me '2015-01-08T00:00:00Z'In another this gives me 2015-01-08T00:00:00-03:00. What I want to know is if there is any way to drop the timezone part so as the time is the same in both time zones.
I would be VERY grateful for any help on this matter. Thank you.
Java SE 8 comes with a new Date & Time API. Have a look at LocalDate and LocalDateTime.
If you are only interested in the format of the time, create a java.text.SimpleDateFormat object to print your time in the format that you want.
http://docs.oracle.com/javase/1.5.0/docs/api/java/text/SimpleDateFormat.html
If you want the time to be printed with the same numbers no matter the TimeZone,
Use String ids[] = java.util.TimeZone.getAvailableIDs();
to get the TimeZone's IDs and find the ID that you want.
In this example, I created two SimpleDateFormat objects set to two different TimeZones. They both print off the same Calendar object. I have taken off the Z in ft2 to remove the time zone portion. By relying on toString(), I think you would be subject to Locale differences in displaying dates, like US MM/dd/yyyy and UK dd/MM/yyyy.
TimeZone tz = TimeZone.getTimeZone("America/New_York");
TimeZone tz2 = TimeZone.getTimeZone("America/Chicago");
Calendar acal = new GregorianCalendar();
SimpleDateFormat ft = new SimpleDateFormat ("yyyy-MM-dd'T'hh:mm:ss Z");
ft.setTimeZone(tz);
SimpleDateFormat ft2 = new SimpleDateFormat ("yyyy-MM-dd'T'hh:mm:ss");
ft2.setTimeZone(tz2);
String date1 = ft.format(acal.getTime());
System.out.println(date1);
String date2 = ft2.format(acal.getTime());
System.out.println(date2);
Output:
2015-01-08T10:36:39 -0500
2015-01-08T09:36:39

Java Date Validation Issue

Here is the validation code for Date of format MM/dd/yyyy.
SimpleDateFormat formatter = new SimpleDateFormat("MM/dd/yyyy");
formatter.setLenient(false);
Calendar cal = Calendar.getInstance();
Date myDate = formatter.parse("01/02/2014888");
cal.setTime(myDate);
When the date string is 01/02/2014888, it passes the validation.
How can I make the validation correctly?
The Calendar class will allow you to create dates in the future, so 2014888 is a perfectly valid year, albeit a ways off. If you want to add additional constraints to the allowable date, you will need to check the values yourself, such as:
if (cal.get(Calendar.YEAR) > endOfTime) {
// do something about it
}

How to get particular parts of a DateTime object?

I have a DateTime object DT which stores current time. When I print DT, I want it to only print the time part, ie HH-MM-SS (H = hours, M = minutes, S = seconds) and ignore the date part.
How can I do this ? For that matter, is it even possible to create a date time object which will only contain HH-MM-SS and nothing related to date ? If that is true, then I can simply print it instead of extracting the HH-MM-SS part.
Thanks.
If you only want the time, you should use a LocalTime instead of a DateTime. You can use DateTime.toLocalTime() to get the time part of an existing DateTime.
If you actually want to keep the DateTime but only reveal the time part when formatting, you can create a DateTimeFormatter with a pattern which only includes the time parts, but I'd usually consider this a design smell.
You can use Java date formatter which is in java.util.Date package.
Like :
Date todaysDate = new java.util.Date();
1. // Formatting date into yyyy-MM-dd HH:mm:ss e.g 2008-10-10 11:21:10
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String formattedDate = formatter.format(todaysDate);
2. // Formatting date into yyyy-MM-dd e.g 2008-10-10
formatter = new SimpleDateFormat("yyyy-MM-dd");
formattedDate = formatter.format(todaysDate);
3. // Formatting date into MM/dd/yyyy e.g 10/10/2008
formatter = new SimpleDateFormat("MM/dd/yyyy");
formattedDate = formatter.format(todaysDate);
With Java you can do it like this
Date obj = new Date() ;
System.out.println(new SimpleDateFormat("hh:mm:ss").format(obj)) ;
but it could be an expensive call.
But jodatime gives LocalTime which you can try out.

How to convert Formatted Date (yyyy-MM-dd) to Unix time in Java?

How to convert Formatted date (yyyy-MM-dd) to Unix time in Java?
I want to declare a date using
Date birthday = new Date(y_birthday, m_birthday, d_birthday);
but this constructor has been deprecated, so I got to use the other constructor which uses Unix timestamp
So, you have the date as a string in the format yyyy-MM-dd? Use a java.text.SimpleDateFormat to parse it into a java.util.Date object:
String text = "2011-12-12";
DateFormat df = new SimpleDateFormat("yyyy-MM-dd");
Date date = df.parse(text);
edit If you need a java.sql.Date, then you can easily convert your java.util.Date to a java.sql.Date:
java.sql.Date date2 = new java.sql.Date(date.getTime());
Use a calendar object if you want more control of the date object
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.YEAR, 2011);
calendar.set(Calendar.MONTH, 11); // indexed month (December)
calendar.set(Calendar.DATE, 12);
Date date = new Date(calendar.getTime().getTime());
The hours, minutes, seconds etc of the current time will be set though so you may want to set those to 0 (manually per field)
If you're using Java 7 then I think there's some much nicer stuff you can use for handling dates

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