CODEWITHSUNDEEP
javadatedatetime
user1708240
user1708240

Reputation: 319

How to format date for use in a URL as a parameter

I am using an API to get a weather forecast up until a particular date in Java.

The requirement for passing a date as a URL parameter is that it must be in "YYYY-MM-DD'T'HH:MM:SS" format. I get input in this format from the user, then get the current system date, and then loop until the desired date. The problem lies in converting the input date string into the date format, incrementing it by one day, and then converting it back to the string format for URL parameter.

I am using the following code to do this but it is giving me incorrect results:

formatter = new SimpleDateFormat("YYYY-MM-DD'T'HH:MM:SS");
Date date1 = formatter.parse(inputtime);
System.out.println(date1);
Calendar c1 = Calendar.getInstance();
c1.setTime(date1);
c1.add(Calendar.DAY_OF_MONTH, 1);  // number of days to add
inputtime = formatter.format(c1.getTime());  // dt is now the new date
System.out.println(c1.getTime());
System.out.println(inputtime);

inputtime is the input by the user. If I give "2014-04-12T00:00:00" as inputtime, date1 is then "Sun Dec 29 00:00:00 PKT 2013", c1.getTime() returns "Mon Dec 30 00:00:00 PKT 2013" and inputtime becomes then "2014-12-364T00:12:00" according to the above code block.

How can this logic error be corrected?

Upvotes: 3

Views: 12277

Answers (3)

Basil Bourque
Basil Bourque

Reputation: 338875

The java.util.Date and .Calendar classes bundled with Java are notoriously troublesome. Avoid them.

That format is defined by the ISO 8601 standard. The Joda-Time library follows that standard's formats as a default for both parsing and generating strings. So does the new java.time package in Java 8.

Your string omits a time zone offset. So, you need to know and specify the time zone intended by that string. Perhaps the time zone is UTC meaning a time zone offset of zero.

A day is not always 24 hours. If you meant 24 hours rather than 1 day, call the method plusHours( 24 ).

Here is example code in Joda-Time 2.3.

String input = "2014-01-02T03:04:05";
DateTimeZone timeZone = DateTimeZone.UTC;
DateTime dateTime = new DateTime( input, timeZone );
DateTime tomorrow = dateTime.plusDays( 1 );
String outputWithOffset = tomorrow.toString();
String output = ISODateTimeFormat.dateHourMinuteSecond().print( tomorrow );

Upvotes: 1

Mengjun
Mengjun

Reputation: 3197

Have a try to change your date pattern from

new SimpleDateFormat("YYYY-MM-DD'T'HH:MM:SS");

to

new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");

Letter  Date or Time Component  Presentation    Examples
y       Year                    Year            1996; 96
M       Month in year           Month           July; Jul; 07
D       Day in year             Number          189
d       Day in month            Number          10
h       Hour in am/pm (1-12)    Number          12
m       Minute in hour          Number          30
s       Second in minute        Number          55
S       Millisecond             Number          978

Upvotes: 2

user3510955
user3510955

Reputation:

You should consider SimpleDateFormat date and time patterns: link

For example, something like this:

formatter = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");

Upvotes: 3

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