Convert a string to a GregorianCalendar - java

How do a I take an input birthday string such as 02 26 1991 and make it into a Gregorian Calendar?
I tried parsing it first but it keeps giving me an error message so I'm not quite sure what I'm doing wrong. I also have other input data before this date. One is another string and one is a double value.

Use SimpleDateFormat to parse the date and then assign it to a Calendar.
DateFormat df = new SimpleDateFormat("dd MM yyyy");
Date date = df.parse("02 26 1991");
Calendar cal = Calendar.getInstance();
cal.setTime(date);
The third line could be replaced with:
Calendar cal = new GregorianCalendar();
but I prefer the first version.

Use a DateFormat as shown here:
Example:
DateFormat dateFormat = new SimpleDateFormat("hh:mm dd/MM/yy");
dateFormat.setLenient(false);
Date d = dateFormat.parse("06:23 01/05/06");
Use the parse() method of the SimpleDateFormat class. You can use setLenient(false) to force strict parsing.

Related

SimpleDateFormat parsing date string incorrectly

I'm trying to parse a String into a Date and then format that Date into a different String format for outputting.
My date formatting code is as follows:
SimpleDateFormat dateFormatter = new SimpleDateFormat("dd/MM/yyyy");
SimpleDateFormat dateParser = new SimpleDateFormat("d/M/yyyy h:m:s a");
String formattedDocumentDate = dateFormatter.format(dateParser.parse(sysObj.getString("document_date")));
The result of sysObj.getString("document_date") is 1/31/2013 12:00:01 AM. And when I check the value of formattedDocumentDate I get 01/07/2015.
Any help is much appreciated.
You are parsing days 31 as months. SimpleDateFormat tries to give you a valid date. Therefore It adds to 1/0/2013 31 months. This is 2 years and 7 month. So you get your result 01/07/2015. So SimpleDateFormat works correct.
One solution for you is to change your date pattern to M/d/yyyy h:m:s a or your input data.
To avoid these tries you have to switch off SimpleDateFormat lenient mode. Then you will get an exception if the format does not fit.
It looks like your input format is actually months first, then days. So should be "MM/dd/yyyy".
So:
SimpleDateFormat dateFormatter = new SimpleDateFormat("dd/M/yyyy");
SimpleDateFormat dateParser = new SimpleDateFormat("MM/dd/yyyy hh:mm:ss a");
String formattedDocumentDate = dateFormatter.format(dateParser.parse(sysObj.getString("document_date")));
Another example like this
SimpleDateFormat sdfInput = new SimpleDateFormat("yyyyMMdd");
System.out.println("date is:"+new java.sql.Date( sdfInput.parse("20164129").getTime() ));
Output is: 2019-05-29
I expect to throw parse exception but not (41)is not a valid month value.
on the other hand if I gave 20170229, system can recognize the February of 2017 doesn't have a lap year and return 2017-03-01 interesting.

convert a date object to Oracle timestamp type string

I want to convert a date object, ex: new Date(), to a string which has a format like Oracle's time stamp type, ex: 21-OCT-13 11.08.13.858000000 AM. I know I could just get each piece of information in the date object like day, month, year, hour, minute, ... to form the Oracle format string but I really want to know is there a utility to do that instead?
Using SimpleDateFormat#format() you would print a Date as
SimpleDateFormat sdf = new SimpleDateFormat("dd-MMM-yy hh.mm.ss.SSSSSSSSS a");
System.out.println(sdf.format(new Date()).toUpperCase());
Output :
21-OCT-13 10.01.38.000000614 AM
See JavaDocs for Date and Time patterns.
Try taking a look at SimpleDateFormats - That would be your best bet and easiest way of doing it.
Eg:
Date date = new Date();
SimpleDateFormat dateFormat = new SimpleDateFormat("hh:mm:ss"); //Hours:Minutes:Seconds
String strDate = dateFormat.format(date);
Use SimpleDateFormat.
Date date = new Date();
SimpleDateFormat sdf = new SimpleDateFormat("your_format_here"); // dd/MM/yy h:mm:ss a
String formattedDate = sdf.format(date);
System.out.println(formattedDate);

Calender issue with time zone

I'm having a weird situation with Java Calendar. I'm using dozer mapper to map the objects.
I want to write a method that will convert this object to the following format. yyyy-MM-dd'T'HH:mm:ss.SSS'Z'
say element 2010-11-11T09:30:47.000Z
public Calender getValue(Date source,Calender c) {
Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("GMT"));
calendar.setTime(source);
return calendar;
}
When I run the program, it is printing
2010-11-11T04:00:47.000Z - Because we are setting the Timezone to be GMT, (9.30 - 5.30 = 4.00)
I want my object to have same format and value.if I don't set TimeZone to GMT, it will show as 2008-11-21T09:30:47.000+05:30.
I want it as 2010-11-11T09:30:47.000Z.
I tried added 5.30 to calender.
calendar.add(Calendar.HOUR, 5);
calendar.add(Calendar.MINUTE, 30)
then it works.But if this is ran from any other place, difference won't be 5.30.So I cannot add 5.30 to calenderget
Is there any way to get rid of this problem? I want to return Calender object.
Any suggestions or help would be much appreciated
Use a pattern. F.E:
String pattern = "yyyy-MM-dd'T'HH:mm:ssZ";
DateTimeFormatter dtf = DateTimeFormat.forPattern(pattern);
Also,
SimpleDateFormat dateformatyyyyMMdd = new SimpleDateFormat("yyyyMMdd");
String date_to_string = dateformatyyyyMMdd.format(dateNow);
you can use SimpleDateFormat like this.
SimpleDateFormat formatter, FORMATTER;
formatter = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
String oldDate = "2011-03-10T11:54:30.207Z";
Date date = formatter.parse(oldDate.substring(0, 24));
FORMATTER = new SimpleDateFormat("dd-MMM-yyyy HH:mm:ss.SSS");
System.out.println("OldDate-->"+oldDate);
System.out.println("NewDate-->"+FORMATTER.format(date));
Output OldDate-->2011-03-10T11:54:30.207Z NewDate-->10-Mar-2011 11:54:30.207

Calculating Date in Java

Ok so I am trying to create a date in this format:
SimpleDateFormat dateformat = new SimpleDateFormat("dd-MM-yy");
I am having trouble calculating that date so that it gives me 1/1/13.
Date newdate = new Date (136199001);
String date = dateformat.format(newdate);
However I can't work out how to do it to get to my desired date. I know I am suppose to work it out from 01/01/70 but I am having trouble. The question : what is the formula to work the date out?
I would say that what you are looking for is this:
new SimpleDateFormat("dd/MM/yy").parse("1/1/13");
You can use calendar object for a specific date. It is much easier.
Calendar cal = Calendar.getInstance();
cal.set(2013, 0, 1); //1st january 2013
Date date = cal.getTime();
SimpleDateFormat dateformat = new SimpleDateFormat("dd-MM-yy");
String dateStr = dateformat.format(date);

Date converter in JAVA [duplicate]

This question already has answers here:
How to parse a date? [duplicate]
(5 answers)
Closed 9 years ago.
I have date like Tue Mar 19 00:41:00 GMT 2013, how to convert it to 2013-03-19 06:13:00?
final DateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
final Date date = bdate;
Date ndate = formatter.parse(formatter.format(date));
System.out.println(ndate);
gives the same date.
Use two SimpleDateFormat objects with appropriate formats and use the first to parse the string into a date and the second to format the date into a string again.
As the first answer says. First parse your date with SimpleDateFormat like this:
Date from = new SimpleDateFormat("E M d hh:mm:ss z yyyy").parse("Tue Mar 19 00:41:00 GMT 2013");
Then use that to format the resulting date object with another instance of SimpleDateFormat like this:
String to = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss").format(from);
See the javadoc of SimpleDateFormat here. Hope that helps.
One major thing that the others have left out is dealing with the timezone (TZ). Anytime you use a SimpleDateFormat to go to/from a string representation of the date, you really need to be aware of what TZ you're dealing with. Unless you explicitly set the TZ on the SimpleDateFormat, it will use the default TZ when formatting/parsing. Unless you only deal with date strings in the default timezone, you'll run into problems.
Your input date is representing a date in GMT. Assuming that you also want the output to be formatted as GMT, you need to make sure to set the TZ on the SimpleDateFormat:
public static void main(String[] args) throws Exception
{
String inputDate = "Tue Mar 19 00:41:00 GMT 2013";
// Initialize with format of input
SimpleDateFormat sdf = new SimpleDateFormat("EEE MMM dd HH:mm:ss z yyyy");
// Configure the TZ on the date formatter. Not sure why it doesn't get set
// automatically when parsing the date since the input includes the TZ name,
// but it doesn't. One of many reasons to use Joda instead
sdf.setTimeZone(TimeZone.getTimeZone("GMT"));
Date date = sdf.parse(inputDate);
// re-initialize the pattern with format of desired output. Alternatively,
// you could use a new SimpleDateFormat instance as long as you set the TZ
// correctly
sdf.applyPattern("yyyy-MM-dd HH:mm:ss");
System.out.println(sdf.format(date));
}
Use SimpleDateFormat in this way:
final DateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
final Date date = new Date();
System.out.println(formatter.format(date));
If you do any calculations or parsing with dates please use JodaTime because the standard JAVA date support is really buggy

Categories

Resources