In my sqlite database I have a table with a field created_at that stores time in ISO8601 as text. In the object corresponding to this table I have two fields String date, String time for the created_at attribute. Now, while querying for this table and creating a corresponding object I am stuck at converting the ISO8601 string to the current user's timezone's date (YYYY/MM/DD), time (XX:YY pm). Could anyone help me out? I thought of using substring to split the string but then the timezone is UTC for ISO8601 strings.

tldr: created_at = ISO8601 time string; need to extract date and time portion from it for the current user.

CodePudding user response：

Read the Wikipedia page on ISO 8601.

java.time

Capture the current moment as seen in UTC.

Instant instant = Instant.now() ;

Generate ISO 8601 string.

String output = instant.toString() ;

The Z on the end of that resulting string means an offset-from-UTC of zero hours-minutes-seconds.

Adjust into a particular time zone.

ZoneId z = ZoneId.of( "Asia/Tokyo" ) ;
ZonedDateTime zdt = instant.atZone( z ) ;

Unfortunately, the ISO 8601 standard does not define a format for a moment as seen in a time zone. The ZonedDateTime#toString method uses a format similar to ISO 8601 but appends the name of the time zone in square brackets. This is a smart solution.

String output = zdt.toString() ; 

Much of your Question in not clear. I am guessing you want to pull the date and time portions from a ZonedDateTime. But I am not sure using such values to query your database makes sense. But if you insist:

LocalDate ld = zdt.toLocalDate() ;
LocalTime lt = zdt.toLocalTime() ;

You can get an ISO 8601 string for each.

String ldOutput = ld.toString() ;
String ltOutput = lt.toString() ;

Notice there is no need for the string manipulations you mentioned in your Question.

CodePudding user response：

I think that you can see this link here you might find some answers.

But for example, you can see this example here. I have a String format and I transform it into a Date object.

DateFormat df1 = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSZ");
String string1 = "2001-07-04T12:08:56.235-0700";
Date result1 = df1.parse(string1);