convert java.sql.Timestamp to java.sql.Date

Question

I have a Timestamp and Date variables and i want to compare it for equality (only date part of course). It was surprise for me that contructor Date(long) saves time part, so this code does not work correct:

date = resultSet.getDate(1);
timestamp = resultSet.getTimestamp(2);    
//...
if (date.equals(new Date (timestamp.getTime())) ...

I solve this with code like:

DateFormat dateFormat = new SimpleDateFormat ("yyyyMMdd");
if (date.equals(dateFormat.parse(dateFormat.format(timestamp)))) ...

Or i can convert timestamp to date in sql query, but i need a timestamp representation too. Is there a better way to cut a time part from Timestamp.

Answer 1

Java 8 approach of conversion:

Date date = Date.valueOf(timestamp.toLocalDateTime().toLocalDate());

And vice versa:

Timestamp timestamp = Timestamp.valueOf(date.toLocalDate().atStartOfDay());

Answer 2

Using the method from this answer we get:

date = resultSet.getDate(1);
timestamp = resultSet.getTimestamp(2);    
Calendar cal1 = Calendar.getInstance();
Calendar cal2 = Calendar.getInstance();
cal1.setTime(date);
cal2.setTimeInMillis(timestamp.getTime());
boolean sameDay = cal1.get(Calendar.YEAR) == cal2.get(Calendar.YEAR) &&
                  cal1.get(Calendar.DAY_OF_YEAR) == cal2.get(Calendar.DAY_OF_YEAR);

It's worth reading the linked answer as it talks about the shortcomings of this method with respects to timezones and so on (and some of the other answers to that question give alternate approaches which you may prefer).