Oracle SQL中java.sql.Timestamp到日期的转换

Question

I have run into this weird Timestamp to Date Conversion issue in Oracle SQL.

Here is the SQL statement:

String INSERT_SQL = String.format("INSERT INTO AUDIT_TASK (%s, %s, %s, %s) VALUES (AUDIT_TASK_SEQ.nextval,?,?,?)",ID,CLASS_NAME,TASK_STEP_TIMESTAMP,OPERATOR);

java.util.Calendar utcCalendarInstance = Calendar.getInstance(TimeZone .getTimeZone("UTC"));
java.util.Calendar cal = Calendar.getInstance();
final PreparedStatement stmt = con.prepareStatement(INSERT_SQL);
stmt.setString(1, audit.getClassName().getValue());
// Save the timestamp in UTC
stmt.setTimestamp(2,new Timestamp(cal.getTimeInMillis()), utcCalendarInstance);

When I execute this statement, while most of the times the creation_date and task_step_timestamp dates are same, but sometimes I get the task_step_timestamp generated with some bogus dates- like '25-APR-0000' or '00-Jan-0001' etc.

• ID | Creation_date | Task_step_timestamp
• 1 |27-APR-2018 17:58:53| 25-APR-0000 09:00:45
• 2 |27-APR-2018 18:06:25| 00-Jan-0001 09:18:25

The data type of task_step_timestamp column in Oracle DB is 'DATE'.

Can some one suggest the cause of this inconsistent conversion of timestamp to date?

Answer 1

I don't understand why you are using String#format here. Just use a regular insert which mentions explicit columns:

String INSERT_SQL = "INSERT INTO AUDIT_TASK (ID, ERROR_MESSAGE, TASK_STEP_TIMESTAMP, OPERATOR) ";
INSERT_SQL += "VALUES (AUDIT_TASK_SEQ.nextval, ?, ?, ?)";
PreparedStatement stmt = con.prepareStatement(INSERT_SQL);

Then bind your values:

stmt.setString(1, audit.getErrorMessage() != null ? audit.getErrorMessage().getValue() : null);
stmt.setTimestamp(2, new Timestamp(cal.getTimeInMillis()), utcCalendarInstance);
stmt.setString(3, audit.getClassName().getValue());

Note carefully that the placeholders, in order from left to right, are for the error message, task step timestamp, and operator. Your original code appears to be binding the parameters out of order. By using an insert statement which explicitly mentions the columns, you may avoid this problem.

Edit:

It also doesn't make sense to me why you are worrying about time zones for your timestamp. Just get the numbers of milliseconds since the epoch, and then let the database store that as UTC:

Timestamp timestamp = new Timestamp(System.currentTimeMillis());
stmt.setTimestamp(2, timestamp);