Timestamp conversion to instant in Java adds unnecessary time offset

Question

I need to be able to convert data fetched from MySQL database that is stored in a "datetime" fields into Java ZonedDateTime object.

ZonedDateTime dt = ZonedDateTime.ofInstant(rs.getTimestamp("Start").toInstant(), UTC_ZONE_ID)

The problem I'm having is that toInstant() adds local time offset to the Timestamp object which I don't need because the datetime is already stored in a UTC format in a database. So when I run the following code:

ZonedDateTime startDT = 
        ZonedDateTime.ofInstant(rs.getTimestamp("Start").toInstant(),Globals.LOCALZONEID);
System.out.println(rs.getTimestamp("start"));
System.out.println(rs.getTimestamp("start").toInstant());

I get:

2017-06-08 13:15:00.0
2017-06-08T17:15:00Z

I need the time component to stay unchanged.

I was unable to find any obvious solution to the problem so am I missing something here?

Answer 1

I think this code snippet answers your question. This takes in a String in a local time zone, converts it to UTC, and stores it in a db.

    //Getting the LocalDateTime Objects from String values
    DateTimeFormatter df = DateTimeFormatter.ofPattern("yyyy-MM-dd kk:mm"); 
    String txtStartTime = "2017-03-29 12:00";

    LocalDateTime ldtStart = LocalDateTime.parse(txtStartTime, df);


    //Convert to a ZonedDate Time in UTC
    ZoneId zid = ZoneId.systemDefault();

    ZonedDateTime zdtStart = ldtStart.atZone(zid);
    System.out.println("Local Time: " + zdtStart);
    ZonedDateTime utcStart = zdtStart.withZoneSameInstant(ZoneId.of("UTC"));
    System.out.println("Zoned time: " + utcStart);
    ldtStart = utcStart.toLocalDateTime();
    System.out.println("Zoned time with zone stripped:" + ldtStart);
    //Create Timestamp values from Instants to update database
    Timestamp startsqlts = Timestamp.valueOf(ldtStart); //this value can be inserted into database
    System.out.println("Timestamp to be inserted: " +startsqlts);

    //insertDB(startsqlts);