Convert yyyy-mm-dd to yyyy-mm-dd HH:mm:ss.SSS-CodePudding

I have a scenario where my input is yyyy-MM-dd and output should be yyyy-MM-dd HH:mm:ss.SSS in java. Example: 2022-03-15 as input, My expected O/P : 2022-03-15 12:00:12.000

CodePudding user response：

yyyy-MM-dd is effectivly a LocalDate. What you're trying to do is convert it to LocalDateTime.

From howtodoinjava.com

You could either set the time to 00:00 with

LocalDate localDate = LocalDate.parse("2019-01-04");

//Beginning of the day
LocalDateTime localDateTime1 = localDate.atStartOfDay();
System.out.println(localDateTime1);

Use the current time with

//Current time
LocalDateTime localDateTime2 = localDate.atTime(LocalTime.now());
System.out.println(localDateTime2);

Or add the 12:00:12.000 with

//Specific time
LocalDateTime localDateTime3 = localDate.atTime(12, 12, 000);
System.out.println(localDateTime3);

Note that you always need the first line of code

LocalDate localDate = LocalDate.parse("2019-01-04");

To format it in a specific way, use SimpleDateFormat

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
String formatedDate = sdf.format(localDate);

CodePudding user response：

You can achieve that by using the following function:

LocalTime myTime = LocalTime.parse("12:00:12.000");    
LocalDateTime myDateTime = LocalDateTime.of(myInputDate, myTime);

and myDateTime will output: 2022-03-15T12:00:12